Data from the

NATIONAL HEALTH SURVEY

Skeletal Maturity of

Youths 12-17 Years

Racial,GeographicArea, and

SocioeconomicDifferentials

UnitedStates,1966-1970

Skeletal age (hand-wrist) and bone-specific skeletal ages (as

assessed by the Health Examination Survey Standard, based primarily on the Greulich-Pyle Radiographic Atlas) of boys and girls

age 12-17 years, by chronological age, race, geographic region,

population size or land use of area of residence, annual family

income, and education of parent.

DHEW Publication No. (PHS) 79-1654

Series 11

Number 167

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Service

National Center for Health Statistics

Hyattsville, Md. October 1978
/“

,

Library of Congress Cataloging in Publication Data

Roche, Alex F.

Skeletal maturity of youths 12-17 years.

(Vital and health statistics: Series 11, Data from the National Health Survey, Data from

the health examination survey; no. 167) (DHEW publication; no, (PHS) 79-1 654)

Includes bibliographical references.

1. Skeletal maturity-United States. 2. Children in the United States–Anthropometry.

3. Health surveys-United States. I. Roberts, Jean, joint author. II. Hamill, Peter V. V.,

joint author. III. Title. IV. Series: United States. National Center for Health Statistics. Vital

and health statistics: Series 11, Data from the National Health Survey, Data from the health

examination survey; no. 167. V. Series: United States. Dept. of Health, Education, and Welfare. DHEW publication; no. (PHS) 79-1654. [DNLM: 1. Age determination by skeleton–

In adolescence. 2. Bone development–In adolescence. 3. Racial stocks. 4. Socioeconomic

factors. W2 A N148vk no. 167.

RA407.3.A347 no. 167 [GN63]

ISBN 0-8406 -0121-2

312’. Q973s [573’.6’710973

78-502
NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

RO’BERT A. ISRAEL, Depu ty Director

JACOB J. FELDMAN, Ph.D., Associute Director for Analysis

GAIL F. FISHER, Ph. D., Associate Director for the Cooperative Health Statistics System

ELIJAH L, WHITE, Associate Director for Data Systems

JAMES T. BAIRD, JR., Ph.D., Associate Director for International Statistics

ROBERT C. HUBER, Associate Director for Afunagenrent

MONROE G. SIRKEN, Ph. D., Associate Director for Mathematical Statistics

PETER L. HURLEY, Associate Directorfor Operations

JAMES M. ROBEY, Ph. D., .4ssociate Director for Program Development

PAUL E, LEAVERTON, Ph. D., Associate Directorfor Research

ALICE HAYWOOD, Information Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

MICHAEL A. W. HATTWICK, M.D., Director

JEAN ROBERTS, Chiej h4edical Statistics Branch

ROBERT S. MURPHY, Clziej Survey F’larming and Development Branch

DIVISION OF OPERATIONS

HENRY MILLER, Chief, Health Examination Fie~ Operations Branch

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specifications established by the National Health Survey, the Bureau of

the Census, under a contractual agreement, participated in the design and selection of the sample, and carried out the first stage of the field interviewing and certain parts of the statistical

processing.

Vital and Health Statistics-Series 11-No. 167

DHEW Publication No. (PHS) 79-1654

Library of Congress Catalog Card Number 78-502
CONTENTS

Introduction ..............................................................................................................................................

Examination Method .................................................................................................................................

Field Radlo~aphy ................................................................................................................................

Training of Assessors ............................................... .............................................................................

Assessment Procedure ...........................................................................................................................

Skeletal Age (Hand-Wrist) Findings ............................................................................................................

Race ......................................................................................... ............................................................

Geographic Re@on .................................................................................. .............................................

Urbm.Rurd ..........................................................................................................................................

Family Income .....................................................................................................................................

Parental Education ...............................................................................................................................

Bone-Specific Skeletal Age Findings .................................................. ........................................................

Race ........................................................................................................................................... ..........

Geographic ReQon ........................................ .......................................................................................

Family Income .....................................................................................................................................

Range of Bone.Specific Skeletal Ages .. .................................................................................................

Onset of Ossification Findings ...................................................................................................................

Race .....................................................................................................................................................

Geographic ReQon ...............................................................................................................................

Family Income .....................................................................................................................................

Epiphyseal Fusion Findings .......................................................................................................................

Previous Studies ....................................................................................................................................

Discussion ..................................................................................................................................................

Race .....................................................................................................................................................

Geographic Re~on ................................................................................................ ...............................

Urban. Rural ..........................................................................................................................................

Socioeconomic Factors .........................................................................................................................

nlness ............................................................................................................... ....................................

Diet ......................................................................................................................................................

Summmy ............................................................................................ .......................................................

References .................................................................................................................................................

Lkt of Detailed Tables ...............................................................................................................................

Appendixes

L Statistical Notes .............................................................................................................................

11, Demo~aphic and Socioeconomic Terns ................. ......................................................................

III. Reliability of Assessments .............................................................................................................

LIST OF FIGURES

1. Mean difference inmonths between skeletal age (hand-wrist) and chronological age forwhite and

Negro boys and white and Negro girls age 6-17 years by chronological age in years: United States,

1963.1970 .......................................................................................................................................

1

3

3

3

4

5

6

19

21

22

25

25

26

27

27

27

29

29

29

29

32

32

33

34

37

38

38

40

41

42

45

52

90

95

97

6

.

Ill
2. Mean difference inmonths between skeletal age(hmd-tist) andchronolo#cd age forwhite boys

and girls and Negro boys and girls age 6-17 years by chronological age in years: United States,

1963.1970 .......................................................................................................................................

3. Difference between actual andexpected mean skeletal age (hand-wrist) forwhite and Negro boys

and girls 6-17 years of chronological age: United States, 1963-1970 ...............................................

4. Relative variability in skeletaf age (hand-wrist) among white and Negro boys and girls age 6-17

years by chronological age in years: United States, 1963.1970 .......................................................

5. Differences between skeletal and chronological a es of boys 12-17 years in studies of Flory

1% (1936),16 Simmons (1944), 17 and Todd (1937) ........................................................................

6. Differences between skeletrd and chronological ages of boys 12-17 years in studies of Fry

(1966), 21 Maresh (1970), 22 Johnston (1962),19 Greulich and Pyle (1959),10 and U.S. youths

(1966-1970) ................................................................................................................................. ...

7. Differences between skeletaf and chronological a es of ~rls 12-17 years in studies of Flory

(1936), 16 Simmons (1944), 17 and Todd (1937)1 #........................................................................

8. Differences between skeletal and chronological ages of girls 12-17 years in studies of Fry (1966),21

Maresh (1970),22 Johnston (1962),19 Greulich and Pyle (1959),10 and U.S. youths (1966-

9. Mean difference in months between skeletaf age (hand-wrist) and chronological age for boys and

girls age 6-17 years by region and chronological age in years: United States, 1963-1970 .................

10. Difference between actual and expected mean skeletaf age (hand-wrist) for boys and girls 6-17

years of chronological age by region: United States, 1963.1970 .....................................................

11. Difference between actual and expected mean skeletal age (hand-wrist) for white and Negro boys

and girls 6-17 years of chronological age by region: United States, 1963-1970 ...............................

12. Mean difference in months between skeletal age (hand-wrist) and chronological age for boys and

girls age 6-17 years by ammaf family income and chronological age in years: United States, 1963-

1970 ............................................................................................................................................... .

13. Difference between acturd and expected mean skeletal age (hand-wrist) for boys and girls 6-17

years of chronological age by annual income: United States, 196$-1970 ........................................

14. Difference between actual and expected mean skeletal age (hand-wrist) for white and Negro boys

and girls 6-17 years of chronqlogicaf age by annual family income: United States, 1963 -1970 .......

LIST OF TEXT TABLES

A. Minimum and maximum acceptable skeletal ages in months using the HES male standards: Health

Examination Survey, 1966.1970 .....................................................................................................

B. Mean differences in skeletal age (years) between Greulich-Pyle and Tanner-Whitehouse assessments

(GP - TW) of the same radiographs .................................................................................................

c. Modaf differences between skeletal age and chronological age (S.A. - C.A. in years) in some Negro

7

10

11

11

11

12

12

20

21

22

23

24

25

4

4

youths in other counties ................................................................................................................ 16

D. Modsd Greulich-Pyle skeletal age levels (S.A. - C.A. in years) in southern Chinese youths ................. 16

E. Modal skeletal age levels (S.A. - C.A. in years) of American youths of Japanese ancestry40 and

Japanese youths in Japan42’43 ....................................................................................................... 17

F. Standard deviations (years) of skeletaf age for U.S. youtiS, ............................................................... 18

G. Standard deviations (years) of skeletaf age in groups of youths outside the United States ................. 19

H. Modaf ages (years) for onset of ossification in selected bones in U.S. white youths ........................... 30

J. Modal ages (years) for onset of ossification in youths of European ancestry living in Europe ............ 31
K. Modal ages for epiphyseal fusion in the hand-tist of U.S. white youths ........................................... 32

L. Reported ages of epiphyserd fusion in Japanese youths ...................................................................... 33

M. Correlation coefficients between skeletal age (Greulich-Pyle) and year of birth in the Fels Longitudinal Study (Roche, unpublished data) ........................................................................................ 35

N. Mean relative differences between parent-offspring pairs in skeletal age (RWT, knee in years) ........... 36

0. Mean skeletrd ages for southern Chinese youths in Hong Kong at various socioeconomic levels

(Low et al., 1964)39 ....................................................................................................................... 38

P. Retardation (years) in age of onset of ossification of hand-wrist centers in malnourished white

youths (data of Dreizen et al., 1958)169 ......................................................................................... 41

v
SYMBOLS

Data not available-----–---–--------–--–—-- ---

Category not applicable--------------—---——-- . . .

Quantity zero---------—---------—---—- -

Quantity more than Obut less than 0.05—- 0.0

Figure does not meet standards of

reliability or precision---------—----—- *

vi
SKELETAL MATURITY

OF YOUTHS 12-17 YEARS: RACIAL, GEOGRAPHIC AREA,

AND SOCIOECONOMIC DIFFERENTIALS

Alex F. Roche, M.D., Fels Research Institute;

Jean Roberts and Peter V. V. Hamill, M.D.,

Division of Health Examination Statistics

INTRODUCTION

This report presents national estimates of

the levels of hand-wrist skeletal maturity among

noninstitutionalized youths age 12-17 years in

the United States, by race, geographic area of

residence, and socioeconomic background, based

on findings from the Health Examination Survey

of 1966-1970. The previous report on these radiographic findings among youths,l which was

limited to the sex differences in skeletal maturity in relation to chronological age, contains a

more comprehensive description of the nature of

skeletal maturation among youths and of the

assessment method used in the survey.

Both the findings in these two reports on

skeletal maturity among youths age 12-17 years

and those from the corresponding reports among

children age 6-11 yearsz $3 are the first national

estimates of skeletal maturity levels made for

these age groups in this or any other country.

These studies provide estimates of known reliability against which present assessments of children and youths can be compared and possible

future changes in skeletal maturation rates, for

the country as a whole, can be judged.

The Health Examination Survey (HES) is

one of the major programs of the National Center for Health Statistics (NCHS), authorized

under the National Health Survey Act of 1956

by the 84th Congress as a continuing Public

Health Service function in determining the

health status of the U.S. population.

Four types of survey programs are used to

carry out the intent of the National Health Survey.4 The Health Interview Survey collects

information from samples of people by household interview and focuses primarily on the

impact of illness and disability within various

population groups. The programs in the Divisions of Health Resources Utilization Statistics

and Health Manpower and Facilities Statistics

obtain health data as well as health resource and

utilization information through surveys of hospitals, nursing homes, and other resident institutions and the entire range of personnel in the

health occupations. The Health Examination

Survey, from which data in this report were

obtained, collects health data by direct physical

examinations, tests, and measurements performed on samples of the population. The latter

program provides the best way of obtaining

actual dia~ostic data on the prevalence of certain medically defined illnesses in the general

population. It is the only effective way to secure

information on unrecognized and undiagnosed

conditions and on many physical, physiological,

and psychological measures within the population, Also it collects demographic and socioeconomic data from the sample population under

study to which the examination findings may be

related.
The Health Examination Survey is organized

as a series of separate programs or cycles each of

which is limited to some specific segment of the

U.S. population and to specific aspects of

health. From data collected during the first

cycle, the prevalence of certain chronic diseases

and the distribution of various physical and

physiological measures were determined on a

cross-section of the defined adult population as

previously described.s ~6

For the second examination survey program,

a probability sample representative of the noninstitutionalized children age 6-11 years in the

United States was selected and examined in

1963-1965. The examination in this cross-sectional study primarily assessed health factors

related to growth and development, as described

in a previous report.7

The third cycle, on which findings in this

report are based, was similar in design and purpose to the preceding children’s program. For

this third survey, a probability sample representative of the noninstitutionalized youths age

12-17 years in the United States was selected for

examination. The examination in this cross-sectional study primarily assessed health factors

related to growth and development, using

methods similar to those in the preceding children’s study supplemented as previously described for this older age group.1 YS

Included were examinations given by a

pediatrician, assisted by a nurse, an examination

by a dentist, tests administered by a psychologist, and a variety of tests and measurements by

laboratory X-ray technicians.

Field collection operations for this youths’

cycle, which started in March 1966, were completed in March 1970. Of the 7,514 youths

selected in the sample, 6,768 youths, or 90 percent, were examined. The response rate was

higher among Negro youths (96.6 percent) than

among white youths (89. 1 percent) and lower

among white girls, particularly at 17 years of

chronological age, than among white boys,

Negro boys, or Negro girls. The extent to which

these differential response rates will affect the

precision of the national estimate for white and

Negro youths is discussed in greater detail in

appendix I. This national sample is representative, and the examined group closely representative, of the 22.7 million noninstitutionalized

youths age 12-17 years in the United States with

respect to age, sex, race, geographic region, population size of place of residence, and rate of

change in population size of place of residence

from 1950 to 1960. The sample design for the

youths’ survey used the same sampling areas and

housing units as the preceding survey among

children. As a result, nearly one-third of the

youths in the present study had also been examined in the children’s survey.

The examinations were conducted consecutively in 40 different locations throughout the

United States. During the single visit, each youth

was given a standardized examination by the

team in the mobile units specially designed for

use in the survey. Prior to this examination,

demographic and socioeconomic data on household members as well as medical history, behavioral, and related data on the youths to be

examined were obtained from their parents.

Ancillary data were requested from the schools

attended by the youths, including their grade

placement, school behavior, adjustment, ~d

health problems known to their teachers. An

additional Health Habits and History form was

compIeted by the youth before he or she arrived

for the examination, and a Health Behavior form

was completed by the examinee while in the

examining center. Birth certificates of the

youths were obtained for verification of age and

for information related to their condition at

birth.

The same methods and measure of skeletal

maturation were used in the examination surveys among children and youths. In planning for

both survey programs, the advice of clinicians

and directors of long-term studies of skeletal

development had been obtained about possible

uses of skeletal maturity levels and methods of

assessing skeletal age from radiographs. The

directors of growth studies conducted independently from 1929 to 1962 at the Brush Foundation in Cleveland, Ohio, and the Department of

Maternal and Child Health at Harvard University

in Boston, Massachusetts—Drs. William Walter

Greulich and Harold C. Stuart–recommended

that Dr. S. Idell Pyle prepare a single standard

from their radiographic series specifically for use

in the Health Examination Survey. The 1964

Manual-the preliminary edition of A Radiographic Standard of Reference for the Growing

2
Hand and Wristg–was prepared for this purpose

by Drs. Pyle and Greulich. This will be referred

to in this report as the “HES Standard.”

The general concept of skeletal maturity, the

methodology by which radiographs were taken

and later assessed, and the quality control measures used have been described in detail and discussed in the first reports on skeletal maturity of

children 6-11 yearsz and youths 12-17 years.1

A brief description of the sample design,

quality control methods, and reliability of the

data, as well as the population and sampling

error estimation procedures used in reporting

the findings of this study, is contained in appendix L Definitions of the demographic terms used

in this report are included in appendix II, and an

evaluation of the reliability of the assessments is

shown in appendix III.

EXAMINATION METHOD

At each of the preselected locations throughout the United States used in this study, the

youths were brought to the centrally located

mobile examination center for a standardized

examination which lasted about 3-1/2 hours. Six

youths were examined in the morning and six in

the afternoon. When each youth entered the

examination center, an oral temperature was

taken and a screening for acute illness was made.

If such illness was detected, the youth was sent

home and reexamined later. All six proceeded to

designated but different stations for the start of

the examination after changing into gymnasium-type shorts, cotton sweat socks, a robe and

(for girls only) a light sleeveless topper. The

sequence of elements in the examination differed for each youth so that all six could be

examined simultaneously during the half day.

The time of each part of the examination was

recorded, but there is no reason to believe that

time of day or sequence of examination would

affect the composition or quality of the radiographic data.

Field Radiography

Each vouth was scheduled to have a 10” x

12“ radiograph of the

which the positioning

right hand and wrist for

was in accordance with

specifications in the Greulich-Pyle Atlas. 10

Although some radiographs were made using

other film sizes when the 10“ x 12“ size was

scarce, this would not have influenced the findings in the assessment method used. Technically

inadequate films could be repeated because they

were developed immediately in the field. Hence

each youth’s record contained a single radiograph showing the dorso-palmar view of his or

her entire hand-wrist with its full complement of

ossifying parts at the time of the examination.

As indicated previously, the decision to radiograph the right hand-wrist rather than the left,

which is the more frequent anthropometric practice, was made on the advice of anthropologist

consultants who were interested also in the use

of related measurement data for equipment

design in which right-side measurements were

preferred. When the selected radiographs used in

the plates from the Greulich-Pyle Atlas and

those from other sources were reproduced in the

HES Standard, they were reversed photographically so they could be used in right-side assessments. Previous reports on lateral differences in

skeletal maturity of the hand-wrist, either for

the area as a whole or bone by bone, have shown

that these are too small to be of practical importance.1 1

Training of Assessors

The assessments of

hand-wrist radiographs

skeletal age from the

of youths age 12-17

years in the H&dth Examination Survey of

1966-1970 were made by nine medical students

at Case Western Reserve University. These

included five of the medical students who had

done the assessments in the 1963-1965 national

survey among children age 6-11 years. This work

was administered under a contract, with Dr. C.

Wesley Dupertuis as project director, for the

National Center for Health Statistics. Under the

direct supervision of Dr. Pyle, training of the

assessors and the implementation of related

quality control procedures were done in the

meticulous manner described previously. 1 When

the ratings and reliability for the new assessor

reached good agreement with those of Dr. Pyle—

the majority of differences within 4 months–

that new assessor started his assessment of the

survey radiographs. Reported evidence from

3
another studyl Z suggests that at the end of this

training procedure the interobserver and intraobserver differences in skeletal maturity ratings

would be similar to those for experienced assessors.

Assessment Procedure

As previously described,l *Z the radiographs

were assessed by comparison with prints of the

series of standards for the male hand-wrist

selected from those in the 1959 Greulich-Pyle

Atlasl 0 and other sources which have been

reversed so they appear to be of the right handwrist as shown in the 1971 Radiographic Standard of Reference of Pyle et al.g The male skeletal age equivalent values shown in that standard

were those used for the assessment of radiographs in both the national surveys among children and youths, with some very slight modification to smooth the skeletal age trend for a few

of the bones.

In making the assessments, the readers did

not have access to the chronological age, the sex,

or other information about the youth. Each

bone on the radiograph of the hand-wrist was

rated separately and interpolation was made

between standards to monthly intervals when

appropriate.

As a quality control measure and to permit

determination of the leveI of reliability of the

assessments throughout this study, independent

replicates were obtained on approximately 1 out

of each 11 films. One randomly selected radiograph in each 23 was rated independently by

another assessor for a measure of interobserver

variability, and one randomly selected radiograph among each 20 was rated independently a

second time by the same reader to give a measure of intraobserver variability. For the latter

set, the time lapse between the first assessment

and the reassessment was sufficiently long that

there was little likelihood of recall. There was

also no indication to the assessor that he was

making a reassessment. Information on the

degree of reliability of these assessments is given

in appendix III.

The order in which the bones were assessed

within each radiograph was as listed in table A.

This table also contains the minimum and maximum bone-specific skeletal ages allowed in the

Table A. Minimum end maximum acceptable skelatal ages in

months using the HES male standards: Health Examination

Suwey, 1966-1970

Hand-wrist bone

Radius .............................................

Ulna ................................................

Cavitate ...........................................

Hamate ............................................

Triquetral ........................................

Lunate .............................................

Scaphoid .........................................

Trapezium .......................................

Trapezoid ........................................

Metacarpal I ....................................

Metacarpal II ...................................

Metacarpal Ill ..................................

Metacarpal IV ..................................

Metacarpal V ...................................

Proximal phalanx 1..........................

Proximal phalanx I I-V .....................

Middle phalanx I I-I V .......................

Middle phalanx V ............................

Distal phalanx 1...............................

Distal phalanx 11, V .........................

Distal phalanx Ill ............................

Distal phalanx IV ............................

Pisiform ...........................................

Adductor sesamoid ..........................

Flexor sesamoid ..............................

~

Skeletal age in months

15

70

. . .

. . .

17

35

68

51

68

25

17

16

17

24

33

15

23

39

15

39

22

32

110

146

158

228

215

197

197

197

197

197

197

197

191

215

209

209

215

215

209

209

209

191

191

191

191

197

197

197

lMinim”m age (according to standard) of radio-oPacity of

epiphysis or carpal.

2one month below “adult” age.

male standard values for this study and in the

preceding one among children. The lower limit

for the bone-specific skeletal age was arbitrarily

set midway between the last standard in which

the particular bone was not radio-opaque and

the first in which it was radio-opaque. Exceptions were made for the three later-ossifying

bones: the pisiform and the adductor and flexor

sesamoids. For these bones the minimum values

allowed were 2 months above the last standard

in which the bones were not radio-opaque.

At the upper end of the range when epiphyseal fusion or maturation was complete for a

particular bone, only the designation “adult”

and not a skeletal age in months could be

assigned. The median ages in months, from the

HES Standard, at which this occurs in boys were

used as the bone-specific skeletal age beyond

4
which only this designation “adult” could be

applied. The maximum allowable values 1

month below this “adult” skeletal age are shown

in table A.

As expected within chronological age intervals, the skeletal ages assigned to the girls were

more advanced than those assigned to the boys.

This occurs because, although boys and girls pass

through essentially the same skeletal maturity

stages, girls tend to mature more rapidly than

boys. Bone-specific female equivalent skeletal

ages were determined during the preparation of

the HES Standard but were not used in the

ass cssment of the survey radiographs. The

method by which these female equivalent skeletal age values were obtained is described in detail

in Pyle et al.g In summary, these ages were estimated using three sets of serial radiographs of

normal U.S. girls. The modal radiograph (in

maturity) for each chronological age group in

each set was assessed against the female standards in the Greulich-Pyle Atlasl 0 and against the

HIM Standard (male). Later these sequential

female equivalent skeletal ages were smoothed.

The skeletal age data for girls in the detailed

tables of this report are given both in terms of

the male standards, as originally assessed, and in

terms of the female equivalent skeletal ages that

were obtained by converting the data recorded

originally. The skeletal age values for the whole

hand-wrist for boys and girls in this report were

determined by computer from the original

bone-specific assessments by averaging the ages

assigned the hand-wrist bones for each youth.

SKELETAL AGE

(HAND-WRIST) FINDINGS

The preceding report on the skeletal maturation of youths age 12-17 years in the United

Statesl describes and analyzes the trend and

extent of variation in the timing and velocity of

this aspect of osseous development by age and

SCX, without regard to racial or socioeconomic

classification. It includes a further analysis of

these trends across the entire age range 6-17

years for boys and girls in the United States, as

well as comparisons with findings from the previous more geographically limited studies in this

and other countries. The national estimates of

skeletal maturity among U.S. children and

youths are based on findings from the Health

Examination Surveys of 1963-1965 and

1966-1970 in which hand-wrist radiographs

obtained for the national probability y samples of

examinees were assessed against the HES Standard for the hand-wrist using the Greulich-Pyle

method, as previously described.

In brief, among youths 12-17 years of age,

the mean skeletal age (hand-wrist) of boys in the

United States has been shown to increase consistently with chronological age from 11.7 years

(140.2 months) for those 12 years of age at their

last birthday (mean chronological age 12.5 years

or 150 months) to 17.1 years (205.4 months) at

chronological age 17 years (mean chronological

age 17.5 years or 210 months). The yearly increment in skeletal age is at a maximum among

boys age 12-14 years and then decreases at ages

16 and 17 years to the same levels found among

boys age 6-11 years. When assessed against the

m~e s&ndard,- the mean skeletal age (handwrist) of girls in the United States increases from

14.6 years (174.9 months) at chronological age

12 years to 17.6 years (211.3 and 211.5

months) at ages 16 and 17 years. During the

6-year time span the yearly increment in skeletal

age for girls is consistently less than that for

boys of comparable chronological age and steadily decreases from a maximum at ages 12 and 13

years across the remainder of the age range as

proportionately more of the girls had reached

the point at which epiphyseal fusion in their

hand-wrists is completed–the upper limit of

skeletal maturation.

On transformation to female equivalent

values, which compensate for the more rapid

skeletal development of girls compared with

boys, the mean skeletal age (hand-wrist) of girls

in the United States increases with chronological

age from 11.9 years (142.9 months) at age 12

years to 15.5 years (185.6 and 186.0 months) at

chronological ages 16 and 17 years, respectively.

The mean lag of skeletal age (hand-wrist)

behind chronological age for boys drops from a

peak of 13.8 months at age 11 years (from the

1963-1965 national survey) to 9.8 months at age

12 years and continues to decrease to less than 1

month at 14 and 15 years before increasing

again to nearly 5 months at age 17 years. Among

girls, the lag of skeletal age (female equivalent

5
values) behind chronological age at 12 years (7.1

months) is slightly less than the maximum value

of 9.8 months at age 11 years (from the

1963-1965 national survey) and decreases

slightly to a minimum of 6.0 months at age 14

years. For girls from age 15 years on, the lag of

skeletal age behind chronological age becomes

progressively greater, reaching a maximum of 24

months at age 17 years. The reasons for these

somewhat inconsistent patterns among older

youths have been discussed in detail in a previous report. 1

Race

White.–The mean skeletal age (hand-wrist)

of white boys in the United States increases with

chronological age from 11.7 years (140.4

months) for those 12 years of age at their last

birthday (mean chronological age 12.5 years or

150 months) to nearly 17.2 years (205.8

months) at chronological age 17 years (mean

chronological age 17.5 years or 210 months) as

shown in table 1. Among these white boys, the

yearly increment in mean skeletal age is at a

maximum of 16.9 months between chronological ages 13 and 14 years and then decreases

to 8.8 months between ages 16 and 17 years.

The mean lag of skeletal age (hand-wrist)

behind chronological age for U.S. white boys

drops from 9.6 months it age 12 years to 0.3

months at age 14 years. The mean skeletal age

exceeds the chronological age by 1.1 months at

age 15 but again lags 1.0 month behind the

chronological age at age 16 and lags by 4-.2

months at age 17 years (figures 1 and 2).

Across the entire age range 6-17 years, mean

skeletal age of white boys increases consistently

with chronological age from 6.2 years (74.9

months) at age 6 years to nearly 17.2 years

(205.8 months) at age 17 years (table 1 and

reference 3). The yearly increment is maximal

+5

r

BOYS

g

w

K

-20

u

u.

~

0

z

w

z -25

I I I 1 I I I I I I I I 1

6 B 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHOAY

+5

r

GIRLS

(female equlvdem]

o

-5 —

-lo —

-15 —

-20 —

-25 —

\

\

.

Negro

1 I I I I I I I I I I I I I

6 8 10 12 14 16 16

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHOAY

Figure 1. Mean difference in months between skeletal age (hand-wrist) and chronological age for white and Negro boys and white and

Negro girls age 6-17 years by chronological age in years: United States, 1963-1970

6
{5 r

o

-5 -

-lo —

-16 —

-20 —

-2s —

WHITE

\

I

I

!

I

L

1

1

1

\

1

Girls ~

[female equivalent]

I I I [ I r I 1 1 I 1 I I

6 8 10 12 14 16 16

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHDAY

+5 —

o

-5 —

-lo —

-15 —

-20 —

-25 —

NEGRO

i

t

i

t

1

I

i

i

,

i

I

I

1

Ciirk ‘

{female equivalent)

I 1 I I I 1 I 1 I I I I I 1

6 6 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHOAY

Figure 2. Mean difference in months batween skeletal age (hand-wrist) and chronological age for white boys and girls and Negro boys

and girls age 6-17 years by chronological age in years: United States, 1963-1970

(16.6, 16.4, and 16.9 months) from age 11 to 14

years and minimal (8.0 months) between 9 and

10 years of chronological age. The maximum lag

of mean skeletal age behind chronological age is

the 14.2 months difference at age 11 years

(from the 1963-1965 national survey).

As measured by the standard deviation, the

variability in skeletal maturity (hand-wrist)

among white boys decreased with chronological

age from maximum values of 17.17 months and

17.77 months at ages 12 and 13 to 10.97

months at age 17 years, The standard deviation

is substantially greater among boys age 12-15

years than among those younger (6-1 1 years) or

older (16 or 17 years). The relative variability

(i.e., 100 times standard deviation divided by

the mean) among white boys decreases during

ages 6-10 years (from 15.3 to 9.0), is slightly

greater again at ages 11-13 years (10.5, 12.2,

11.3), and decreases steadily from age 14 years

to 18 years (from 8.5 to 5.3).

Among white girls in the United States, the

mean skeletal age (hand-wrist ), assessed against

the male standards, increases from 14.5 years

(174.3 months) at age 12 years to 17.6 years

(21 1.7 months) at age 17 years. Across the

entire age span 6-17 years in the two national

surveys, the mean skeletal ages (male standard)

for white girls increase from 7.5 years (89.7

months) at age 6 to 17.6 years (21 1.7 months)

at age 17. The yearly increment in mean skeletal

age for white girls in the youth age range is at a

maximum of 12.2 months between ages 12 and

13 years and decreases to the minimum of 0.2

month at age 17. In the earlier survey of children, the largest annual increment was 19.2

months for the interval 10-11 years. The mean

skeIetaI age (male standard) of white girls is

about 2 years in advance of their chronological

ages at 12, 13, and 14 years (24.3, 24.5, and

23.9 months, respectively). This advancement

decreases to a minimum of 1.7 months at 17

7
years. The means of the girls (male standard) are

consistently in advance of chronological age for

the entire 6-17-year range by values that are

maximal (about 24 months) at ages 12-14 years

and minimal at age 17 years.

The variability of skeletal age (hand-wrist),

as measured by the standard deviation, is greater

among younger white girls of 12 and 13 years

(14 and 13 months) than among those 14-17

years, where the st~dard deviatio~s are 9 to 10

months. The variabilityy, relative to the mean,

decreases from a maximum at age 12 and levels

off from ages 15-17 years. The variability in

skeletal age for white girls, when considered

across the entire age span 6-17 years, is greatest

at age 10 (s%= 17.28 months) and least from 14

years on (9-10 months). When considered in

relation to the size of the mean, the relative variability is greatest at age 6, somewhat higher at

7-10 years, and then declines to minimum values

at ages 15-17 years.

When conversion is made to the female

equivalent values for white girls in the youth age

range, the mean skeletal ages increase from 11.9

years (142.3 months) at 12 years to 15.5 years

(186.0 months) at age 17. The yearly increment

in these mean values is slightly greater at ages 12

and 13 years (12.5 and 13.1 months) than at

other ages and later decreases to the minimum

(0.2 month) at age 17.

The lag of mean skeletal age (hand-wrist)

behind chronological ‘age, in terms of the female

equivalent values, for white girls decreases very

slightly from 12 years (7.7-month lag) to 14

years (6.1 months) then steadily increases to a

maximum at age 17 (24.0 months).

From the two national studies, during the

age span 6-17 years (reference 1-3 and table 1),

the mean skeletal age (hand-wrist, female equivalent values) for white girls increases from 6.4

years (76.7 months) at age 6 years to 15.5 years

(186.0 months) at chronological age 17 years.

The yearly increment in these values is maximal

(14.2 months) between ages 11 and 12 years and

nearIy as great between 13 and 14 years, then

from 14-16 years decreases to levels that do not

differ significantly from those in the younger,

6-11-year, age groups. The lag of skeletal age

(hand-wrist, female equivalent values) behind

chronological age for white girls, which increases

from 1.3 months at age 6 to 9.9 months at age

11, becomes slightly smaller at ages 12-14 (lags

of 7.7, 7.2, and 6.1 months) and then increases

to the maximum value of 24 months at age 17

years (figures 1 and 2).

White girls consistently are more advanced in

skeletal maturity than white boys across the

entire 6-17-year age range when both are

assessed against the single male standard. However, when the female equivalent values for girls

are used in this comparison (figure 2), the mean

values for younger white girls generally tend to

exceed those for white boys up to age 12 years, ,

although these mean differences are negligible at

ages 7-9 years. From 13 years on, the mean

skeletal ages for white girls are significantly

lower than those for white boys; these mean differences increase steadily with chronological age

from 2.0 months at age 13 years to 19.8 months

at age 17 years. This disparity is due, in part, to

the fact that there are progressively fewer girls in

the older age groups whose hand-wrist bones are

still maturing; hence these comparisons are made

between the majority of boys and only the later

maturing girls, as discussed in a previous report.1

Negro.-Among Negro boys in the United

States, the mean skeletal age (hand-wrist) values

increase steadiIy from 11.6 years (138.7

months) at age 12 to 16.9 years (202.4 months)

at age 17 years. Across the age range 6-17 years

in the two national surveys (references 1-3 and

table 1), mean skeletal age (hand-wrist) for

Negro boys increases from 6.6 years (79.0

months) at age 6 years to 16.9 years (202.4

months) at age 17 years. The yearly increment is

maximal (21.9 months) between ages 12 and 13

years and minimal (9.0 months) between ages 14

and 15 years. When considered over the entire

age range of the two surveys combined, the

yearly increment is maximal (21.9 months)

between ages 12 and 13 years and minimal

between 8 and 10 years (5.5 and 5.9 months).

The mean lag of skeletal behind chronological

age for Negro boys is greatest (11.3 months) at

age 12, decreases to only 1 month at 13-14

years, and then consistently increases to 7.6

months at age 17.

Skeletal maturity (hand-wrist) of Negro boys

is more variable at age 13 years (s% = 19,69

months) and least variable at 17 years (standard

deviation of 11.37 months). The variability relative to the mean for Negro boys shows a similar
pattern of change but decreases more consistently with chronological age from 13 to 17 years

than dots the standard deviation.

For the age span of the children’s and

youths’ surveys combined, variability, as determined by the standard deviation, is greatest at

age 13 and least at ages 8-10 years (10.11,

10.58, and 10.27 months). However, relative

variability is greatest among the Negro boys 7

and 6 years old and least among the oldest age

group (17 years).

For Negro girls age 12-17 years, mean skeletal agc (hand-wrist, male standard) increases

from 14.9 years (178.4 months) at chronological

agc 12 years to 17.5 years (210.5 months) at

chronological age 17 years. Across the 6-17-year

tigc span from the two national surveys, the

rnwm skeletal age (hand-wrist, male standard)

for Negro girls increases consistently from 7.7

years (91.9 months) at chronological age 6 years

to 17.5 years (210.5 months) at age 17 years.

The mean skeletal ages (hand-wrist, male standard) for these Negro girls are consistently in

advance of their chronological ages across the

6-1 7-year span by amounts that increase consistcmtly from a minimum of 9 months among

8-year-olds to values in excess of 24 months at

12-14 years. Later this advancement decreases to

Icss than 1 month at age 17 years.

The yearly increment for Negro girls is greatest at ages 12-15 years (9-11 months) and then

decreases to less than 1 month (0.3 month)

between chronological ages 16 and 17 years. The

maximum yearly increase, for the total span

6-17 years, is between ages 9 and 11 years (16.3

and 16.1 months), and the minimum is among

the oldest Negro girls (0.3 month between 16

and 17 years).

The variability and the relative variability in

skeletal age (hand-wrist, male standard) among

Negro girls is largest at age 12 and least at 15

years in the survey of youths. When the data

from both surveys are considered, the standard

deviation is greatest at ages 9-12 years (18.33,

17.65, 17,28, 16.72 months) and least at ages 15

and 16 years (8.35 and 9.36 months, respectivcly) for Negro girls.

On conversion to female equivalent values,

the mean skeletal age (hand-wrist) of Negro girls

in the youth age range increases from 12.2 years

(146.4 months) at age 12 to 15.4 years (184.5

months) at age 17 years. The yearly increment

in these mean values is largest between 13 and

14 years (12.6 months) and later decreases to

less than 1 month (0.3 month) between ages 16

and 17 years. The lag of mean skeletal age

(hand-wrist, female equivalent values) behind

chronological age for Negro girls is 6 months or

less from 12 to 15 years and later increases to

exceed 25 months at age 17.

Across the age span 6-17 from the two

national surveys, the mean skeletal age (handwrist, female equivalent values) for Negro girls

increases from 6.6 years (78.9 months) at age 6

to 15.4 years (184.5 months) at age 17 years.

The yearly increase is greatest between ages 11

and 12 years (17.6 months) and slows to a negligible amount (0.3 month) between ages 16 and

17 years. Only at age 6 years does the mean

skeletal age exceed the chronological age for

Negro girls, and then by less than 1 month.

From 7 to 17 years, these female equivalent

values lag behind chronological age. As seen in

figure 2, the lag increases from 7 to 11 years,

and decreases to less than 6 months at ages

12-14 years, after which it increases to the maximum of more than 25 months at age 17.

When both Negro girls and boys are assessed

against the male standards, the girls are consistently more advanced in skeletal maturity than

the boys are across the entire age range 6-17

years. This is similar to the findings among white

children and youths. When comparison is made

with the female equivalent skeletal ages of girls,

the mean skeletal ages for Negro boys consistently exceed those for Negro girls from age 13

to 17 years, which is consistent with the findings

among white youths. Only for the two oldest

groups (16 and 17 years) are the mean differences large enough to exceed the 95-percent

confidence limit for the national estimates (statistically significant at the 5-percent level).

Among the younger age groups, 6-12 years, the

mean skeletal ages for Negro girls slightly exceed

those for Negro boys except at 6 and 8 years.

White-Negro. –White boys age 6-11 years are,

on the average, generally slightly less mature

skeletally than Negro boys. However, the pattern is reversed at age 12-17 years, when the

mean skeletal ages of white boys generally tend

to exceed those for Negro boys in the United

States (figures 1 and 3). Only at ages 10 and 13

9
Figure 3. Difference between actual and expected mean skeletal

aae (hand-wrist) for white and Negro boys and girls 6-17

y;ars of chronological age: United States, 1963-1970

years do exceptions to the above trends occur.

By contrast, white girls are slightly but consistently less mature skeletally than Negro girls, 6

through 15 years except at 8 years where the

mean values are identicaL Only among 16- and

17-year-old girls is this pattern reversed, and the

differences are slight at these older ages.

These white-Negro differences can be compared with the corresponding differences for

height and weight of U.S. children and youths

from these national surveys. 13 Negro boys were

slightly taller at 7-9 years and white boys were

slightly talIer from 9 to approximately 12 years;

Negro girls were consistently talIer than white

girls were from 7 to 14 years, after which the

white girls were consistently taller. The mean

weights of Negro boys were less than those of

white boys at all ages except 13 to 14 years; the

mean weights of Negro girls were greater than

those of white girls at 11 to 15 years. It is also

relevant to note that the Health Examination

Survey data yield estimates of median age at

menarche of 12.80 years in white girls and 12.52

years in Negro girlsl 4 since age at menarche is

known to be associated closely with the rate of

skeletal maturation.1 5

There is no significant or consistent pattern

of racial

maturity

age span

10

differen~es in variability of skeletal

among either boys or girls across the

6-17 years (figure 4). However, Negro

boys and girls tended to be slightIy more variabIe in skeletal maturity than white boys and

girls.

Comparisons with other studies in the

United States. –Some previously reported skeletal maturity data for white children in the

United States are shown graphically in figures

5-8. These data have been adjusted to a common

Greulich-Pyle zero line to facilitate comparison.

This is necessary because there are only quasiunits of skeletal maturity. The data relate to

modal skeletal ages within chronological age

groups, that is, those above the zero line are

advanced (modal skeletal age exceeds mean

chronological age) and those below the zero line

are retarded in comparison with the GreulichPyle standards. The Greulich-Pyle standards 0

were derived from a selected group of white

Cleveland youths of upper socioeconomic status

who were born between 1917 and 1942 and

were radiographed close to birthdays and halfbirthdays. By a painstaking method in which

radiographs were arrayed in order of maturity,

within sex- and age-specific groups, one radiograph was selected as the standard for each

chronological age group because it was considered most representative of the central tendency of the skeletal maturity level for the group.

This selection was made from 100 radiographs

for each sex at each age.

The mixed longitudinal data of Floryl 6

were obtained from white Chicago youths of

above average socioeconomic status who were

born between 1904 and 1917. Flory had available 100 radiographs for each sex at each age; all

these radiographs had been taken within 2 weeks

of a birthday. From these he selected the radiographs he considered best represented the central tendencies of his groups. These selected radiographs are about 1 year retarded in maturity in

comparison with the corresponding GreulichPyle standards (figures 1 and 3). Simmonsl 7

reported data from white Cleveland youths,

most of whom were included among those

studied by Greulich and Pyle.l 0 These youths

were radiographed near each birthday. The sample size varied from 68 to 198 for each year of

age in each sex. Simmons excluded some girls at

older ages who had surpassed the upper limits of

the standards. Consequently, the means for girls

at ages beyond 14 years have not been included
20

r

BoYS 20

Iii

h

~

4\ 15

, \

\

$

6

\

Ha .

/

\

10 \

\

-- .-., 0 ~. . 10

-----

\

\

\

\

\

6

\ Negro

White 5

01 , , , t , I I I o

6 8 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST 61RTHDAY

GIRLS

\

1 1 1 1 1 t I , I 1 a I 1

6 B 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST SIRTHOAY

Figure 4. Relative variability in skeletal age (hand-wrist) among white and Negro boys and girls age 6-17 years by chronological age in

years: United States, 1963-1970

+0.6 -

0.0 -

-0.6 -

-1.0 -

aow

.- FIory (1936)18

. . . .. Simmcms(19gl)%7 /

..+

_Tcfld (1937)

,..

/

/

/

/

/

%. ..””

“%... ,.”

...

,/’ \

\

,/’

\

---- /’

.,,,,

15 17 1s

CHRONOLOGICAL AGE IN YEARS

Figure 5. Differences between skelatal and chronological agas of

boys 12-17 years in studies of Flory (1936),16 Simmons

(1944),17 antiTodd [1937).la

in figure 3 because the proportion excluded is

unknown. The means reported by Simmons,

after adjustment for the use of Todd standards,

were within 0.5 year (skeletal age) of the Greulich-Pyle standards at most ages.

In 1937 Toddl 8 published standards derived

from a group of white Cleveland youths of all

BOYS

+1.0 --

Fry (1966)2’ ~

g

...... Maresh(1970) M

. . . . Johnston[1962)

< ..- Greulichand Pyle (le59)f0

y — Lhited States{1966.1970)

----

----

----

\

--- ......................

‘\ ----,,. -

.-.~.

.\ ./

. . . . . . ------- -.

I 1 I I 1 1 I

12 13 14 15 16 17 lB

CHRONOLOGICAL AGE IN YEARS

Figure 6. Differences between skeletal and chronological ages of

boys 12-17 years in studies of Fry (1966),21 Maresh

(1970),22 Johnston (1962),19 Greulich and Pyle (1959),10

and U.S. youths (1966-1970)

socioeconomic levels. These youths were born

between 1915 and 1936 and radiographed near

each birthday and half-birthday. The standard

plates were chosen to represent the central tendencies for skeletal maturity level within age- and

sex-specific groups. The sample size within each

group varied from 42 to 161. The standards of

11
+1.0

+0.5

0.0

-0.5

-1.0

-1.5

GIRLS

FlorY (19361’6 ,./

Z.Z Simmons (lS#)

— Tcdd (1937)

/

‘\ ,/’ \

\ /

WJ I 1 I I I I

12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Figure 7. Differences between skeletal and chronological ages of

girls 12-17 years in studies of Flory (1936),1G Sim-mons

(1944,17and Todd (1937)18

Todd were about 0.5 year lower than those of

Greulich and Pyle at 12-14 years; the differences

were much sma.Ilerat later ages. It is tempting to

ascribe the differences between the skeletal

maturity levels reported by Todd,l 8 Simmons,1 7 and Greulich and Pylel 0 to variations

in socioeconomic status among the groups of

youths studied by these workers. This leaves

unexplained the relative lack of differences at

later ages. This may be due, in part, to the systematic exclusion of youths who were too

mature to be assessed.

Greulich and Pylel 0 reported data from the

Harvard Growth Study. The group of white

Boston youths included was of middle socioeconomic status, born between 1930 and 1939, and

examined near each birthday. The size of the

groups varied from 63 to 67 for each age in each

sex. The mean skeletal ages (Greulich-Pyle) were

very close to the mean chronological ages.Johnstonl 9 reported mixed longitudinal data from

middle-class Philadelphia white youths born

between 1937 and 1955. The major ethnic

strains in this group were Italian and British.z0

These youths were radiographed at random

+1.0

r

GIRLS

1

. +0.5 .-.7, *.:2.-+

iii .,/.,’ ~-

w I

----s. ;

.

......

. ,. .

-1

t

---Fry (1966)2’ ~

:

-1.0 . . . . .. Maresh (1970] ,g

< .. . . . Johnston (1962) A

~ --- Greulich and Pyle (1959)’0

— United States (1SS6.1970)

5 \

L(J

g

-1.5

t

12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Figure 8. Differences between skeletal and chronological agesof

girls 12-17 years in studies of Fry (1966) ,21 Maresh

(1970),22 Johnston (1962),19 Greukh and Pyle (1959),10

and U.S. Youths (1966.1 970)

chronological ages and the group size varied

from 23 to 50 for each annual interval in each

sex. All the mean skeletal ages for each sex were

about 0.5 year in advance of the Greulich-Pyle

standards.

Cross-sectional skeletal age data from some

white Nebraska youths of middle socioeconomic

level have been re~orted.z 1 These children were

born between 19~2 and 1954 and were radiographer at random ages. The group included 25

youths of each sex within each annual interval.

The means were below the Greulich-Pyle standards in the boys but not in the girls. In each sex

the differences between the mean levels reported

by Fry and those of the Greulich-Pyle standards

did not exceed 0.6 year. Mareshz z reported

mixed longitudinal data from a group of middle

class white Denver youths. These youths were

born between 1915 and 1955, but most of the

radiographs were taken after 1947 and close to

birthdays and half-birthdays. The group size

12
ranged from 21 to 43 for each 6-month interval

in each sex. The median skeleta.Iages for these

youths were between 0.5 and 1.0 year below the

Greulich-Pyle standards from 12 through 17

years, Data have been reported by Malina and

Johnston,Z8 .who used Todd assessments of

about 20 white Philadelphia youths of each sex

for each annuaI interwd from 12 to 16 years.

After adjustment to a Greulich-Pyle baseline,

their data for boys show an advancement in

skeletal age of about 1 year except at 15-16

years, when the advancement is 1.6 years. The

girls, however, are retarded by about 0.5 year.

These previous studies of groups of white

U.S. youths indicate that sex differences in

mean levels were small. This does not mean that

girls did not mature more rapidly than boys but

that the differences between the mean skeletal

ages for the two sexes were slight when assessments were made against sex-appropriate standards,

The present national survey data for white

boys, as noted earlier, are markedly below the

HES reference standards at 12, 13, and 17 years

but not at the intervening ages. These reference

standards were derived from and closely match

those of the Greulich-Pyle Atlas.10 The levels

and patterns of change across age for white boys

from the national survey are not in agreement

with those reported from earlier smaller groups

of U.S. white boys.lo~ lG-19~ zl-z~

The mean skeletal maturity levels of white

girls from the national survey (female equivalent

values) are best considered in two different age

periods (12-14 and 15-17 years). From 12 to 14

years the mean leveIs are about 0.5 year lower

than the Greulich-Pyle standards; these findings

are similar to those reported by Todd,l g Fryjz I

and Maresh.zZ However, at later ages (15-17

years), the mean female equivalent values for

white girk from the natiomd survey fall markedly behind the Greulich and Pyle standards

until the difference is about 18 months at 17

years. It must be emphasized that all the

national survey radiographs were assessed against

a single set of male standards. Consequently, the

present findings probably reflect both real differences in level between white girls in the

national survey and the Greulich-Pyle standards

and systematic sampling bias in the sex-associated differences in skeletal maturity levels used

to transform the values assigned to the girls

against the male standards when obtaining

fema.Ieequivalent wdues.

At 17 years (mean chronological age = 17.5

years) the mean skeletal age for white boys is

17.1 years and the corresponding mean skeletaI

age for girIs (fema.Ie equiwdent values) is 15.5

years. The latter value was obtained after transforming the mean observed value of 17.6 years

which had been obtained using the male standards. The actual difference between the mean

values assigned to the boys and girls at 17 years,

when both were assessed against the male standards, was only 0.5 year. At younger ages the

actual sex difference on the male standards was

considerably larger; for example, at 12 years the

difference was 2.8 years. This decreasing actual

sex difference, at ages after 14 years, leads to

misleading female equivalent values because the

sex differences used to obtain the latter were

too large at these older ages. However, the errors

introduced by this transformation are systematic

and constant across all racial, socioeconomic,

and other groupings. This subject is discussed in

detail in an earlier reportl and is considered in

the “Discussion” section of this report.

Practically no previous data are available

concerning the skeletal maturity status of groups

of white U.S. youths of more specific ancestry,

nor were such data recorded during the Health

Examination Survey. Toddz 4 reported insignificant differences in maturity status between 315

U.S. children and youths, both of whose parents

were born in Italy (usually southern Italy or

Sicily) and 201 children and youths, both of

whose parents were born in the United States,

most of whom were not of Italian ancestry.

These children and youths, who were age 5-13

years, were examined cross-sectionally. From

this study Todd concluded that the data showed

no evidence of race-linked differences although,

of course, there were few children in each ageand sex-specific group. Furthermore, he did not

control for possibIe socioeconomic differences.

Comparison with forei~ studies. –The available data have been collated concerning the

skeletal maturity levels of youths in countries

that have contributed substantially, by emigration, to the U.S. population. In order, these

13
countries are Germany, Italy, Great Britain

(excIuding Ireland), Ireland, Austria-Hungary,

Canada, and the U. S.S.R.2s Unfortunately, relevant reports are available only for England and

Poland.

A major source of information concerning

skeletal maturity levels of British youths is the

differences between Greulich-Pyle and TannerWhitehousez632 7 assessments of the same radiographs.z1J28‘3 0 These data are relevant irrespective of the specific groups studied. It is important

to note the Tanner-Whitehouse standardizing

sample consisted of cross-sectional and serial

radiographs of British youths, most of whom were

from Scotland. The number of subjects per year

for each sex in the Tanner-Whitehouse standardizing sample is about 150, but the sample did

not include youths over 16 years. This led to

problems at the upper end of the scalez7Y28

which apparently have been remedied to some

extent by enlarging the standardizing sample,

redefining the criteria for grades, and eliminating

some grades. This revised system of Tanner and

Whitehouse is referred to as “TW-II.”27

The reported findings summarized in table B

concern studies made using the original TannerWhitehouse Method (TW-1). Problems in standardization and rating criteria at the upper end of

the TW-I scale are presumably responsible, in

large part, for the irregularity of the findings,

especially in older girls.

All the reported comparisons show lower

mean values for Greulich-Pyle skeletal ages than

for Tanner-Whitehouse skeletal ages in boys. In

girls the data are less regular. In the older girls

studied by Fry2 1 and by Andersen, 28 GreulichPyle skeletal ages tended to be higher than the

corresponding Tanner-Whitehouse values. Theoretically, these variations could be due to differences between the two in the methods of

weighting the bone-specific skeletal ages (or

scores). It has been shown, however, that this is

not an important factor.z 9 There is no doubt

that the reported differences almost entirely

reflect variations between the standardizing samples used by Greulich and Pylel 0 and by Tanner

et zd.z G To a lesser extent, they may be due to

systematic bias in assessment. Consequently, the

differences in table B can be interpreted as

showing the variations in skeletal maturity status

between the group of white youths in C1eveland

and several pooled groups in Britain. As mentioned earlier, inferences from these data concerning the comparative rates of maturation of

youths in the United States and several pooled

groups in the United Kingdom (U. K.) can be no

Table B. Mean differences in skeletal age (years) between Greulich-Pyle and Tanner-Whitehouse assessments (Gp - TW) of the same

radiographs

Chronological age and sex

Bow

12.0 years ....................................................................................................................

13.0 years ....................................................................................................................

14.0 years ....................................................................................................................

15.0 years ........................................................o........................................o..................

16.0 years ............................................ .............. ...... .......... ..........................................

17.0 years ............................................................ .......... ..............................................

Girls

12.0 years ....................................................................................................................

13.0 years .................................o............. .................... .................................................

14.0 years ....................................................................................................................

15.0 years .......................... ..........................................................................................

16.0 years ....................................................................................................................

17.0 years ................................................. ................................ ...................................

Andersen, Rocha et al., Clark,

19%1 196828 197129 19743’J

Mean difference

-0.9

-0.7

-0.4

. . .

. . .

. . .

0.0

+1.1

+’0.5

. . .

. . .

. . .

-0.3

-0.7

-0.7

-0.4

-0.5

-0.4

-0.5

0.0

+0.2

+1.1

+1.7

. . .

-0.5

-0.4

-0.1

. . .

. . .

. . .

-0.7

-0,5

-0.5

. . .

. . .

. . .

-1.0

. . .

. . .

. . .

. . .

. . .

. . .

. . .

. . .

. . .

. . .

. . .

NOTE: Fry–Nebraska, white youths; Andersen-Danish youths in Copenhagen; Roche et al.–Australian youths of British ancestry; Clark-Saskatchewan youths.

14
more than tentative because neither the Greulich-Pyle nor the Tanner-Whitehouse scale is

based on a representative national sample.

When the levels of skeletal maturity in U.S.

and U.K. youths are compared by considering

the reports of investigators who applied both the

Greulich-Pyle and Tanner-Whitehouse methods

to the same youths, the groups studied are irrelevant except in regard to sample size, which will,

of course, affeet the reliability of the estimates.

Fryz 1 studied 25 youths of each sex at each

annual interval; this study has been described

earlier. The group studied by Andersenzs

included about 50 Copenhagen youths of each

sex at each annual interval. Mixed longitudinal

data from 23-51 Australian youths at each year

of age have been reported by Roche and his

coworkers.z g Clarks O assessed 12 youths at 12

years. All the means reported by Andersen indicate slight retardation (0.2 to 0.7 year) of the

British standardizing group in comparison with

Greulich-Pyle standards, except in girls at 14-16

years (0.2 to 1.7 years advanced). The differences reported by othersz 1$28‘30 are similar for

boys. However, Fryz 1 and Andersen,z 8 unlike

Roche et al.,29 found the Greulich-Pyle skeletal

ages were more advanced than those of TannerWhitehouse in girls age 14 years or older. In general, these studies indicate that the standardizing

sample of boys of Tanner et al.z 7 was about 0.5

year behind the Greulich-Pyle standardizing sample in mean skeletal maturity level, but the differences among these reports preclude any generalization for girls. Paradoxically, when a group

is given a higher mean rating on the TannerWhitehouse scale than on the Greulich-Pyle

scale, this shows that the standardizing group

used to construct the Tanner-Whitehouse scale

matured more slowly than the group used to

construct the Greulich-Pyle scale.

Further evidence concerning the skeletal

maturity levels of British children is available

from the mixed longitudinal data of Roche31

obtained from essentially the same group of

Australian children of British ancestry as that

studied by Roche et al.z 9 The size of this group

ranged from 42 to 51 for each sex at each year

of age. The mean Greulich-Pyle skeletal ages in

these Australian youths were very close to the

mean chronological ages, within 0.2 year. This

suggests that youths of British ancestry born and

living in Australia mature slightly more rapidly

than British youths living in Great Britain.

Kopczynska3 z reported cross-sectional data

from about 6,000 Polish youths age 12 to 16

years living in Warsaw. The mean skeletal ages

(Greulich-Pyle) tended to be less than the mean

chronological ages, especially in the boys.

Other comparisons. –The literature allows

only tenuous comparisons between reported

skeletal maturity levels of groups of white and

Negro youths in the United States. Toddz 4

using cross-sectional radiographs of 149 Negro

children and youths (age range not reported)

tentatively concluded there were no modal differences in skeletal maturity level between

Negro and white boys but that Negro girls

tended to be more advanced than white girls.

Malina3 3‘36 and Malina et al.36 made Tanner-Whitehouse assessments of some middle to

upper-middle socioeconomic class white youths

(IV = 35) and some lower socioeconomic class

Negro youths (IV = 168) in Philadelphia, age 12

to 14 years. Both groups of youths were slightly

in advance of the Tanner-Whitehouse standards

except at 12 years in girls, when the difference

was very small. The differences between the

means for the two groups (white and Negro)

were small, but the Negroes were slightly more

advanced (O. 1 year, boys; 0.4 year, girls) despite

the lower socioeconomic status of the Negro

groups. These findings suggest that, at the same

socioeconomic level, the skeletal maturity status

of Negro youths may be slightly in advance of

that of white youths.

Cross-sectional data have been reported from

139 rural Jamaican youths age 12 to 16 years

living about 15 miles northofKingston.37 At all

ages, the mean Tanner-Whitehouse skeletal ages

were less than the mean chronological ages.

These differences tended to increase with age

becoming comparatively large in girls between

14 and 16 years (table C). These Jamaican

youths were retarded skeletally in comparison

with the Negro youths in Philadelphia studied

by Malina.3 3‘3 4 ~3f’ Michaut-Barthod38 reported

Greulich-Pyle skeletal ages for Dakar youths of

Ovoloff ethnic origin. The group size ranged

from 18 to 60 for each sex within 6-month age

groups. These youths were markedly behind the

15
Table C. Modal differences between skeletal age and chronological age (S.A. - C.A. in years) in some Negro youths in

other countries

Chronological

age and sex

Boys

11.5 years ........................

12.0 years ........................

12.5 years .................... ....

13.0 years ........................

13.5 years ........................

14.0 years ........................

14.5 years ........................

15.0 years ........................

15.5 years ..... ...................

—Girls

11.5 years ........................

12.0 years ........................

12.5 years ........................

13.0 years ........................

13.5 years ........................

14.0 years ........................

14.5 years ....... .......... .......

15.0 years ........................

15.5 years ........................

Modal difference

-0.2

. . .

-0.7

. . .

–0.7

. . .

-0.8

. . .

-0.8

-0.6

. . .

-0.4

. . .

-0.5

. . .

-1.1

---

-1.7

. . .

-1.3

-1.3

-1.4

-1.2

-1.1

-1.2

-1.1

. . .

. . .

-7.7

–1.3

-1.8

-1.4

-1.6

-1.6

–1.8

..-

NOTE: Marshall et al.–rural Jamaican youths (TannerWhitehouse Scale): Michaud-Barthod–Ovoloff youths in Dakar

(Greulich-Pyle Scale),

Greulich-Pyle standards. The mean differences

between the chronological and skeletal ages

ranged from 1.1 to 1.8 years, tending to be

greater in girls. When adjustments are made for

the differences in rating scales used, it becomes

clear that skeletal maturation was markedly

delayed in the Dakar youths compared with

those in Jamaica. But as noted earlier, skeletal

maturation was also delayed in the Jamaican

Negro youths compared with those in Philadelphia.

Cross-sectional data from 3,624 southern

Chinese youths in Hong Kong who were born

between 1944 and 1950 have been reported 39

(table D). Greulich-Pyle assessments showed a

marked tendency to skeletal retardation in these

Chinese boys at 12 and 13 years, but later the

mean differences between chronological and

skeletal ages were small. This tendency to lesser

delay in skeletal maturity in the boys as adolescence proceeded may reflect genetic differences between the groups studied by Low et

ala g and Greulich and Pylel O in a~e-associated

rates of skeletal maturation. From 12 to 15

Table D. Modal Greulich-Pyle skeletal age levels (S.A. - C.A. in

years) in southern Chinese youths

Chronological age and sex

Boys

12.0 years ..................................................

13.0 years ..................................................

14.0 years ..................................................

15.0 years ..................................................

16.0 years ..................................................

17.0 years ..................................................

Girls

12.0 years ..................................................

13.0 years ..................................................

14.0 years .............. ....................................

15.0 years ..................................................

16.0 years ..................................................

17.0 years ..................................................

Low et al.,

196439

Modal skeletal age

-1.1

-1.5

-0.2

+0.2

+’0.7

+0.6

+0.1

+0.3

+0.4

+0,4

+0,5

+0.1

years, however, it might also reflect the demonstrated differences between the Greulich-Pyle

skeletal maturity levels and those present in the

national probability sample of U.S. white and

Negro boys. The Chinese girls studied by Low et

ala g tended to be very slightly advanced skeleta.lly in comparison with the Greulich-Pyle

standards at all ages from 12 through 17 years.

This is different from the findings of the present

survey of U.S. white and Negro girls who were

behind the Greulich-Pyle standards during the

same age range.

Greul.ich40 reported cross-sectional data

from a “representative sample” of American

born youths of Japanese ancestry living in the

San Francisco area of California (table E). This

sample included 20 to 41 youths of each sex at

each annual interval who had been born between

1939 and 1944. The mean skeletal ages41 of

these Japanese-American youths were advanced

over their mean chronological ages for all age

groups in each sex. In the boys, these differences

were small except at 16 years, but in the girls

the y were large from 13 through 16 years.

Sutow4 Z reported cross-sectional data from

Japanese youths in Hiroshima who were born

between 1936 and 1941 and examined within 1

month of a birthday. These youths constituted

the normal control group when irradiation

effects were being studied in Hiroshima youths.

The group sizes varied from 56 to 107 for each

sex at each age. Standards were selected from

16
Table E. Modal skeletal age levels (S.A. – C.A. in years) of

American youths of Japanese ancestry40 and Japanese

vouths in JaPan42’43

Chronological

age and sex

BOVS

12,0 years ........................

12.5 years ........................

13.0 years ........................

13.5 years ........................

14.0 years ........................

14.5 years ........................

15.0 years ........................

15.5 years ........................

16.0 years ........................

16.5 years ........................

17.0 years ........................

—Girls

12.0 years ........................

12.5 years ........................

13.0 years ........................

13.5 years ........................

14.0 years ........................

14.5 years ........................

15.0 years ........................

15.5 years ........................

16.0 years ........................

16.5 years ........................

17.0 years ........................

17.6 years ........................

Modal skeletal age

+0.4

. . .

+0.6

..-

+0.6

. . .

+0.5

. . .

+1.2

-..

+0.5

+0.6

---

+1.4

-..

+1.0

---

+1.0

. . .

+1.1

---

+0.6

. . .

-1.0

. . .

-0.6

. . .

-1.2

-..

-1.0

.-.

-1.5

-..

-1.0

-1.2

---

-2.0

. . .

-1.5

-..

-1.5

. . .

-1.5

.-.

–2.0

---

-

---

-0.5

-..

0.0

---

0.0

---

0.0

..-

+0.5

. . .

---

-0.5

-..

0.0

. . .

–0.5

---

-0.5

---

-0.5

..-

-0.5

these radiographs by a procedure similar to that

used by Greulich and Py1e44 and these standards

were a&essed against the Greulich-Pyle Atlas by

Sutow.A z These assessments show that, by comparison with the Greulich-Pyle standards, the

modal levels of skeletal maturity were low in

these youths, particularly in the girls, in whom

the mean retardation exceeded 1 year at each

annual age interval.

These data of Greulich and Sutow show

marked differences between the skeletal maturity levels of American youths of Japanese ancestry and Japanese youths in Japan, with the former being the more advanced. It must be

stressed that these data were derived from

youths born between 1936 and 1944; the current differences may be smaller.

That such a secular change has, in fact,

occurred is shown by recent findings. The skeletal maturity standards of Sugiura and NakazawaA 3 indicate that Japanese youths living in

Nagoya have median skeletal ages that are now

very close to the Greulich-Pyle standards. Similarly, Ashizawa4 E reported Tanner-Whitehouse

skeletal ages for Japanese youths living in

Tokyo. The means for the boys were about 1

year in advance of the Tanner-Whitehouse standards, but the corresponding differences for the

girls were very small. If transformed to a Greulich-Pylel 0 baseline, this would imply that the

boys were about 0.5 year in advance of the

Greulich-Pyle standards and that the girls were

about 0.5 year behind them. Kimura46 reported

mean Tanner-Whitehouse skeletal ages for 137

Japanese youths age 12-17 years. These were

about 0.5 year in advance of the mean chronological ages in each sex, implying that the mean

levels would have been close to those of the

Greulich-Pyle standards.

As suggested by Greulich,40 it is reasonable

to conclude that the differences between the

skeletal maturity levels of youths of Japanese

ancestry in California and those living in Japan

in the 1950s are likely to be environmentally

determined although the possibility of selective

migration cannot be excluded. The more recent

findings of Sugiura and Nakazawa,43 Ashizawa,zs and Kimura46 suggest that these earlier

differences have been greatly reduced, if not

eliminated. This rapid change supports the view

that the difference; reporte~ earii& were Iarzely .

environmentally determined. They are als~ in

agreement with changes in rates of growth and

sexual maturation occurring in Japan in recent

decades that have been reported in other

studies.4 T‘4 g

One can infer, however, that genetic factors

are also involved in differences between mean

skeletal maturity levels of Japanese youths and

U.S. white youths from data provided by

Kimura.s0)51 He reported that skeletal ages

were less advanced in a group of male Japanese

youths than in a group of hybrid JapaneseAmerican youths. The members of both groups

had been reared and cared for in the same Japanese orphanage environment.

Variability of skeletal ages. –The standard

deviations of the various reported skeletal ages

for ,groups of U.S. white youths can be used as a

gau~e of variability to compare earlier findings

with those in the national survey (table F).

There is considerable agreement among the

studies of white youths, although the groups

17
Table F. Standard deviations (Years) Of skeletal a9e for United States youths

Flory, Johnston, Fry, Malina,l Malina,2 United States

Age and sex 193616 %% 196219 196621 197053 197053 White Negro

Boys

12 years .............................................................

13 years .............................................................

14 years .............................................................

15 years ........o...................o.............................l..

16 years .............................................................

17 years .............................................................

Girls (female scale or equivalent)

12 years .............................................................

13 years .............................................................

14 years .............................................................

15 years .............................................................

16 years .............................................................

17 years .............................................................

1.0

0.8

1.1

1.1

1.1

1.1

1.1

1.1

0.9

0.8

0.7

0.6

0.9

0.9

1.0

1.1

1.2

1.2

1.1

1.2

1.3

1.1

0.9

0.7

0.7

0,9

1.0

1,0

0,9

1,1

1.1

1.2

0.9

1.2

0.9

0.5

Standard deviation

1.4

1.5

0.9

. . .

. . .

. . .

1.4

1.2

1.3

. . .

. . .

..-

1.1

. . .

. . .

. . .

. . .

. . .

0.9

.-.

..-

.-.

. . .

. . .

1.2

0.9

. . .

. . .

. . .

. . .

1.1

1.1

. . .

. . .

. . .

. . .

1,4

1.5

1.2

1.2

1.1

0.9

1.0

0.9

0.7

0.7

0.7

0.7

NOTE: Flory, Bayley, Johnston, Fry-white youths; Malinal–white Philadelphia youths; Malina2–Negro Philadelphia youths.

studied differed in socioeconomic variability and

in their range of chronological ages. There is,

however, a slight tendency for the standard deviations from the national survey to be larger than

those reported by others for boys 12-15 years; a

similar tendency is not present in the data for

girls.

At all ages, the national survey data for both

white and Negro youths indicate that skeletal

maturity levels are less variable, judged by the

standard deviations, in girls than boys. The

white-Negro differences in variability are negligible (table F). Within the other reported

studies, a tendency to a similar sex difference

was present only at the oIder ages.1G~19~sz

These sex differences at the older ages may only

reflect the truncated distributions caused by

many girls reaching the maximum values that

can be assigned.

When the variability of skeIetal ages is compared between the white and Negro groups in

the national survey, in terms of the coefficient

of variation (figure 4), it is clear that Negro boys

tend to be considerably more variable than

white boys except at 12 years. The pattern of

differences between the white and Negro youths

is less consistent in the girIs; the mean skeletal

ages are more variable in the white girls at 13,

15, and 16 years but less variable at 12, 14, and

17 years. This lack of a consistent pattern in the

findings for boys and girls in the coefficient of

1.3

1.6

1.4

1.3

1.4

0.9

1.1

0.8

0.9

0.6

0.7

0.8

variation might reflect the comparatively small

samples of Negro youths. Long ago, Toddz 4

considered, after amdysis of data from a smaller

group, that skeletal maturity was more variable

in American Negroes than whites. The present

findings provide limited support for his view.

Reported standard deviations for the group

of Australian youths studied by Roche31 are

smaller than those for the national survey

youths; however, those reported by Low et a.1.t9

for Chinese girls are larger (table G). Much of

these differences could reflect variations

between these studies in the scheduling of examinations. The Australian youths were seen very

c1os e to birthdays and half-birthdays, the

Chinese children and the U.S. survey children

were examined at random chronological ages.

The latter procedure would have increased the

measures of variability. Furthermore, there was

a much wider range of socioeconomic status in

the group of Chinese youths than in the Australian youths and possibly even the national survey

youths. This also would tend to increase the

variability. The variability of skeletal ages in the

groups studied by Andersenz 8 and Marshalland

his associates y is similar to that found in the

national survey. As in the national survey, variability tended to be less in older girls in the

groups studied by Low and his coworkers 9 and

Andersen.z 8 The data of Marshall and his

associates y show a tendency to less variability

18
Table G. Standard deviations (years) of skeletal age in groups of youths outside the United States

Chronological age and sex

Boys

12,0 years ............................................................................................................

12.5 years ............................................................................................................

13.0 years ...................m.m......................................................................................

13.5 years ............................................................................................................

14,0 years ............................................................................................................

14.5 years ............................................................................................................

15.0 years ............................................................................................................

15.5 years ............................................................................................................

16.0 years ............................................................................................................

16.5 years ..................... .......................................................................................

17.0 years ............................................................................................................

17.5 years .........m.............m....................................................................................

Girls

12.0 years ......................... ...................................................................................

12.5 years ... ,.,, .,,..!.,. ............................................................................................

13,0 years ............................................................................................................

13.5 years .................................... ........................................................................

14.0 years ............................................................................................................

14.5 years ............................................................................................................

15.0 yaars ......o...........o....o....................................................................................

15.5 years ......mm...o...............................................................................................

16.0 years ............................................................................................................

16.5 years ............................ ............ ....................................................................

17,0 years ................................... .........................................................................

17.5 Vaars ................................................................................................. .. .........

Standard deviation

0.7

. . .

0.7

. . .

. . .

. . .

..-

-..

. . .

---

. . .

---

0.8

. . .

0.8

---

..-

. . .

-..

. . .

.-.

..-

.-.

---

. . .

0.9

-..

0.8

---

1.0

.-.

1.1

. . .

1.0

---

1.0

. . .

0.9

. . .

1.1

.-.

1.1

. . .

1.1

. . .

0.8

..-

0.7

1.3

---

1.5

. . .

1.3

.-.

1.0

. . .

1.4

..-

1.6

-..

1.3

---

1.3

..-

1.1

. . .

1.3

. . .

1.0

.-.

0.8

---

Marshall et al.,

197037

---

1.2

. . .

1.6

.-.

0.8

.-.

1.1

. . .

..-

---

..-

. . .

0.7

. . .

0.5

---

0.6

.-.

0.6

-..

.-.

. . .

---

NOIE: Roche–British youths in Australia; Andersen-Danish youths; Lowetal.-Chinese youths; Marshall etal.-Nego youthsin

Jamaica.

in Negro Jamaicans than in U.S. Negro youths.

This may reflect a relatively homogeneous and

low socioeconomic level in Jamaica.

Geographic Region

Analysis of the national survey data by geographic region shows that for all racial groups

combined, youths in the South are slightly more

advanced skeletally and those in the Midwest are

less advanced in this aspect of development, on

the average, than those in either the Northeast

or West Regions of the United States (table 2).

This regionzd differential is present among both

boys and girls over the total age span 12-17

years but is not consistent at the individual years

of chronological age and may be confounded by

unequal racial distributions (figure 9). It is

emphasized, however, that these regional differences are small. The total regional differences

for either sex do not exceed the 95-percent confidence limits for such estimates from this study.

The four regions into which the United States

was arbitrarily divided for sampling and administrative reasons in this national survey are so large

geographically and so heterogeneous that any

real differences among smaller regions that may

exist in the skeletal maturity of youths within

this country would probably be masked.

Mean skeletal ages (hand-wrist) of boys age

12-17 years (mean chronological age of 15.0

years or 180 months) range from 14.7 years

(175.9 months) in the South to 14.5 years

(174.0 months) in the Midwest. However, for

girls (assessed against the male standards) the

values range from 16.5 years (19 7.5 months) in

the South to 16.3 years (196.0 months) in the

Midwest.

Among boys, the mean skeletal ages for

those in the South exceed those in the other

three regions of the country only at chronological ages 12 and 16 years; at ages 12, 14, 15, and

16 years the mean skeletal ages of those in the

19
+5

o

-5

-lo

-15

-20

-25

BOYS

Northeast

----- Midwest

‘---- South

------ West

.

1 1 I I 1 I 1 1 I I 1 1 I I

6 B 10 12 14 16 lB

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHDAY

+5

o

-5

-lo

-15

-20

-25

GIRLS

\

,

.

\

‘<,,

v

— Northeast

----- Midwest

‘---- South

.............. .... West

1 I I I I I I I 1 I I I t I

6 8 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARS AT LAST BIRTHOAY

Figure9. Mean difference in months between skeletal age(hand-wrist) andchronological age for boys andgirls age6-17years by region

and chronological age in years: Unitad States, 1963-1970

Midwest are lower than elsewhere in the United

States.

For girls at chronological ages 15-17 years,

the mean skeletal ages of those in the South

exceed those in the other three regions; however, only at age 12 years are girls in the Midwest less skeletally mature, on the average, than

girls living elsewhere in this country.

If the age-specific mean skeletal ages for

boys in the four regions combined applied in

each individual region, boys in the South would

be expected to be the most skeletally mature

(on the basis of the chronological age distribution) and those in the Northeast, rather than the

Midwest, would be expected to be the least

skeletally mature, on the average. When the

expected skeletal ages (on the basis of chronological ages) are determined for girls, those in

the Midwest would be expected to be the least

skeletally mature, and those in the South and

West would be most advanced, on the average.

The negligible difference between the actual and

expected mean values in each region indicates

that differences in the chronological age distribution of boys or girls among the regions probably account for much of the actual but small

mean regional differences in skeletal maturity

among youths in the United States (figure 10).

The variability of skeletal maturity, as measured by the standard deviation (table 2) or interquartile range (tabIe 8), tends to decrease with

increasing chronological age among youths (boys

and girls) in each region.

The regional pattern of skeletal maturity

among youths age 12-17 years is more consistent

and different from that found among children

age 6-11 years in the preceding national survey.3

Boys age 6-11 years in the Northeast are the

most skeletally mature and those in the South

the least advanced in this respect. Among girls

age 6-11 years, the mean values are highest in

the Midwest and lowest in the West, though, as

20
I

Northeast Midwest South West

1

=,.,,,,,,,

~ 12.17 years

GIRLS

Fiaure 10. Difference between actual and expected mean skel- .

etai age (hand-wrist) for boys and girls 6-17 years of

chronological age by ragion: United States, 1963-1970

in the youth survey, all these mean values are

within the 95-percent confidence limit for such

estimates (not statistically significant).

When white youths only are considered,

boys age 12-17 years in the South are slightly

more advanced skeletally and those in the Midwest slightly less advanced in this respect, on the

average, than boys living elsewhere in the

Nation. Among girls age 12-17 years, those in

the South are also slightly more advanced and

girls in the Midwest slightly less mature skeletally than girls living elsewhere in the United

States (table 3 and figure 11). The mean values

for white boys age 12-17 years (mean chronological age of 15.0 years or 180 months) range from

14.8 years (177.3 months) in the South in 14.5

years (174.2 months) in the Midwest and for

white girls from 16.5 years (197.5 months) in

the South to 16.3 years (195.9 months) in the

Midwest. All these values are for assessments

against the maIe standards.

The regional pattern for skeletal maturity

among Negro youths differs somewhat from that

among white youths. Negro boys age 12-17

years in the West tend to be more skeletally

mature and those in the South less skeletally

mature, on the average, than Negro boys living

in the other regions. Negro girls in the Midwest

are more skeIetaIIy mature and those in the West

less skeletally mature than Negro girls living elsewhere in the Nation. The mean skeletal age

values for Negro boys age 12-17 years (mean

chronological age of 15.0 years or 180 months)

range from 14.6 years or 174.9 months for those

in the West to 14.3 years or 172.0 months for

those in the South; among Negro girls in the

same age range the values range from 16.5 years

or 197.8 months in the Midwest to 16.4 years or

196.2 months in the West.

Urban-Rural

There is no consistent pattern of urban-rural

differences in skeletal maturity among either

boys or girls in the youths’ age range in the

United States (table 4). This finding is similar to

that for children 6-11 years old in the previous

national survey.3 Unlike the situation in some

other countries, this implies a relative lack of

differences between urban and rural areas of the

United States in the genetic and environmental

factors that influence the rate of skeletal maturation and physical growth in generals 4

The mean skeletal age (hand-wrist) for boys

age 12-17 years (mean chronological age of 15.0

years or 180 months) in either urban or rural

areas is 14.6 years or 174.9 months. For girls the

mean values (male standards) in both the urban

and rural areas are 16.4 years (196.6 months,

urban; 196.5 months, rural).

For both boys and girk in urban areas, the

mean values are slightly higher for those living in

the largest (3 million or more) urbanized areas.

For those living in rural areas, there are no consistent differences dependent on whether they

21
Figure 11. Difference between actual and expected mean skeletal age (hand-wrist) for white and Nagro boys and girls 6-17 years of

chronological age by region: United States, 1963-1970

live on farms or dependent on the size of the

non farm community in which they live.

Family Income

There is no consistent relationship between

the skeletal maturity levels of youths age 12-17

years in the United States and the size of their

family income (table 5 and figure 12). However,

those from the higher income levels of $10,000

and over per year appear to have slightly, but

not significantly, higher mean values than those

with lesser incomes.

Among boys age 12-17 years (mean chronological age 15.0 years or 180 months), the mean

skeletal age (hand-wrist) for those with annual

family incomes of $10,000 and over is 14.6

years or 175.5 months compared with 14.5

years (174.5 and 174.6 months) in the two

broad income groups below $10,000

($5,000-$9,999; under $5,000). If only those in

extremes of the income distribution are considered, the mean skeletal age (hand-wrist) of

boys in families with $15,000 or more annual

income is nearly identical with that for the

entire group with $10,000 and over income

(175.8 months compared with 175.5 months),

while among those with annual family income of

less than $3,000 the mean skeletal age is slightly

higher than for all those in the bracket under

$5,000 (175.6 months compared with 174.5

months). The difference (all ages combined)

between those with annual family incomes

greater than $15,000 (175.8 months) and those

with annual family incomes less than $3,000

(175.6 months) is trivial.

22
+5r

BOYS GIRLS

0

-6

10

-15

-20 — Less than $5,000

I

------ $5,000.$9,999

I

----- $l0,0000rmOre

-26

r

t I I I 1 r I I I I I t I

6 6 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARSAT LAST BIRTHDAY

+5

o [

-5 —

-10 —

-15

-20 — Lessthan $5,000

-----$5,000.$9,999

----- $l0,0000rmOre \

I I I I I I I I I I I I I J

6 8 10 12 14 16 18

CHRONOLOGICAL AGE IN YEARSAT LAST BIRTHOAY

Figure 12. Mean difference in months between skeletal age (hand-wrist) and chronological age for boys and girls age6-17vearsbv

annual family income andchronological age in years: United States,-1963-1970 - - - -

A nearly similar pattern ofassociation exists

between family income and the skeletal maturity of girls age 12-17 years (mean chronological

age 15.0 years or 180 months). The mean skeletal age is greatest among those with an annual

family income of $10,000 or more (16.5 years

or 198,1 months) and about the same (16.3

years) in the two broad lower income groups. At

the extremes of the income ranges, the mean

skeletal maturity level of those with a yearly

family income of $15,000 or more is 197,9

months or just slightly less than the mean of

198,1 months for all those with a yearly family

income of $10,000 or more. As for boys, at the

lowest income level ($3,000 a year or less) the

mean skeletal age of girls (male standard) is

197.0 months, which is slightly greater than for

all girls in families with annual incomes under

$5,000. Despite this lack of a clear-cut association with income when all ages are combined, it

is clear that in the girls, but not the boys, those

with annual family incomes in excess of $15,000

were considerably more mature than those in

lower income groups at age 14-17 years.

When the effect of differences in the chrono1ogiczil age distribution among the various

income level groups is removed, boys age 12-17

years in the highest income level famiIies

($1 OJJOO a year and over) are slightly more

advanced skeletally than expected and those in

the lowest income level group (under $5,000)

are less advanced than expected in this respect;

the differences are slightly more marked than

among younger boys age 6-11 years, but not

large enough to possibly reflect more than the

effect of sampling variability (figure 13). The

pattern of deviation in skeletal maturity from

that expected among girls 12-17 years across

income differs somewhat from that shown for

boys and younger girls, but the differences again

are negligible.

Because of a possible confounding effect of

racial differences on the preceding analysis of

income-related variations, the national survey

23
-i

:

z

~o

z

n

~

u! Less than S5,0Q0 $5,000.$9,999 $10,OCQor more

%.

g +5 _

$

GIRLS

0

~

.

w

<

A

$

!5

;

z

$ 0

z

0

:

Less than $5,000 $5,000-$9,999 S1 0,000 or more

1+

x

:

g

Figure 13. Difference between actual and axpected mean skeletal age (hand-wrist) for boys and girls 6-17 Years of

chrono-logical age by annual fa”mily inc;me: United States,

1963-1970

data have been considered separately for whites

and Negroes. Among white boys age 12-17 years

there is even less association between skeletal

maturity level and family income than that

noted for boys of all races combined (table 6).

The mean skeletal age values are identical for

those with $10,000 or more and those with

under $5,000 annual family income (175.4

months) and nearly identical (175.5 months)

with those in the family income bracket of

$15,000 and over. Furthermore, boys in the

lowest income level families, less than $3,000

reported annual income, have slightly higher

mean levels (176.4 months) than the others.

White girls appear to show an association between skeletal maturity and family income similar to that for girls of all races combined–

slightly higher means for those in the upper

income IeveIs.

Both Negro boys and girls age 12-17 years in

the higher income level families ($10,000 or

more per year) are slightly more advanced skeletally than those in families with income levels

beIow $5,000. Mean skeletal age for Negro boys

(mean chronological age 15.0 years or 180

months) in families with incomes of.$ 10,000 or

more is 14.6 years or 175.8 months compared

with 14.4 years or 172.6 months for those in

families with incomes of under .$5,000. For

Negro girls there is a large difference between

the mean skeletal ages (male standard values) for

those in families with $10,000 and over annual

income (17.2 years, 206.6 months) and the corresponding ages for those in the bracket under

$5,000 (16.4 years, 196.7 months). At the

extremes of family income considered, the mean

skeletal age for Negro boys was markedly higher

(15.6 years, 187.8 months) for those in families

with incomes of $15,000 or more than for the

entire group in families with incomes of.$ 10,000

or more (14.6 years, 175.8 months). However,

the mean skeletal age was also slightly higher

among those with family incomes less than

$3,000 (14.5 years, 174.2 months) than for the

entire group with family incomes less than

$5,000 (14.4 years, 172.6 months). Among

Negro girls, the pattern of differences between

mean skeletal ages and family income were even

less consistent. To some extent, the inconsistencies in each sex might reflect the effect of

smzdl samples sizes at the extremes of the distribution of family incomes.

The mean skeletal ages of Negro boys were

slightly lower than those for white boys age

12-17 years in families with less than $10,000

annual income (less than $3,000;

$3,000-$5,000; $5,000-$9,999) but essentially

the same at income levels of $10,000 and over.

Although the difference is large for those with

family incomes exceeding $15,000, the Negro

sample is small, and consequently this estimate

is unreliable. Negro girls, in the age range 12-17

years, were slightly more mature skeIetally than

white girls across all three broad income groups

(under $5,000; $5,000-$9,999; $10,000 and

24
+lo — BOYS +1o

g

$

0

~

u

Cl

<

A +5 —

+5

$

:

3

z

,.,.:..,

$ ....,

b ‘~<:.

.:.,.

,

:.?.

E

ho o

i rz

:

$

Lessthan $5,Q20 $5,000.$e,999 $10,000 or mare

-5 — -5

~ whk8,&ll years ~ whke,12-17Years ~ Nqro,6.11 wars ~ NW0,12-17YW3

Fimsre 14. Difference between actual and exuected mean skelatal acre (hand-wrist) for white and Negro boys and girls 6-17 years of

chronological age by annual family in~ome: United States, 1963-1970 -

over). The opposite was true in both of the

extreme groups (under $3,000 and $15,000 or

more), but the small sample sizes reduce the reliability of these findings.

When the effect of differences in the chronological age distribution between the two largest

racial groups within income level groups is

removed, Negro boys 12-17 years of age are less

mature than expected skeletally and Negro girls

more mature than expected in this respect across

income levels, although the deviations from the

expected are not large enough to be statistically

significant (figure 14).

Parental Education

The association between skeletal maturity

and parental education among white and Negro

youths–both boys and girls–is even less clear

than that with family income (table 7). Those

youths whose first parent (the father if he was

still present in the household) had completed 13

years or more of formal schooling were very

slightly more advanced skeletally than those in

the same race-sex group with lesser parental education. This differential was slightly more evident among boys than among girls. The differences noted are much too small to be statistically significant.

BONE-SPECIFIC SKELETAL

AGE FINDINGS

In the Greulich-Pyle method of assessment,

the skeletal maturity of the hand-wrist assigned

to an individual youth is based usually on the

average of the ages assigned those of the youth’s

31 hand-wrist bones that are radio-opaque but

not classified as adult. While some investigators

use the median and others assign an age to the

whole area without recording separate skeIetal

ages, the common practice of using the average

has been followed in this report as in the previous ones.l’s Although, in general, there is

good concordance among the bone-specific

skeletal ages for an individual, the differences

are real and may be important.

25
The order of onset of ossification and the

rates of maturation of individual bones vary considerably among individual children and youths.

It is probable that there are similar individual

differences in the order of epiphyseal fusion, but

few findings have been reported. As a result of

these variations, there are differences between

the skeletal ages assigned to individual bones in a

single radiograph. For youths in the age range of

concern in this study, 12-17 years, nearly all the

31 hand-wrist bones have become radio-opaque,

but their maturation is incomplete. There are

only 2 hand-wrist bones in which the onset of

ossification is normally delayed until age 12

years or later–these are the adductor and flexor

sesamoids in boys and the flexor sesarnoids in

girls. “

Several factors may be responsible for the

differences that occur commonly among the

skeletal ages assigned to individual bones within

a single hand-wrist radiograph. The selection of

standards by Greulich and Pylel 0 may have

been imperfect. That is, bones each assigned the

same skeletal age in a standard might, in fact,

individually differ in actual skeletal age. This

would not explain the largely random nature of

the variations noted. Errors occur during the

assessment of radiographs. These might be systematic; for example, an assessor or group of

assessors might systematically assess a particular

bone higher than the real level. The variations

due to the assessors might, of course, be random, in which case, when the direction of the

errors are taken into account they would balance each other when group data are considered,

but they could cause or increase the variation

among bone-specific skeletal ages in a single radiograph. Reported data indicate that the comparability and replicability of bone-specific skeletal

ages are lower for the cm-pals than for the other

hand-wrist bones.Es ~E6 This could increase the

variability of the skeletal ages recorded for these

bones.

Differences in skeletal maturity levels among

the bones of a single hand-wrist might result

from variability within individuals that is random in a population. Thus it is possible that

while the population means for all bones could

be at the same level of maturity in children of a

particular age, there could still be variations in

leveI within individual children. Alternatively,

when differences are noted among the skeletal

ages assigned to a radiograph, they could reflect

real genetically or environmentally determined

population differences. That is, a particular bone

or group of bones may systematically be less

mature or more mature than the other handwrist bones in a defined population.

Race

For each of the 31 hand-wrist bones the

mean skeletal age of white boys exceeds that for

Negro boys age 12-17 years in the United States.

The racial differences in the mean values are,

almost without exception, small enough to be

within the 95-percent confidence limits for estimates in this study. This pattern of white boys

being more skeletally mature than Negro boys

for each bone is generally consistent at each

single year of age, except at age 13 years where

30 of the 31 bones (all but the capitate) are

more skeletally mature in Negro than in white

boys. Minor exceptions at other individual ages

are detailed in table 9—the pisiform at age 17,

the adductor sesarnoid at ages 12 and 17, the

flexor sesamoid at ages 14 and 17, and middle

phalanx IV at age 17.

In contrast to the findings among boys

divided on the basis of race, Negro girls of 12-17

years generalIy are more advanced skeletally for

each individual bone than are white girls. Mean

skeletal ages for Negro girIs slightly exceed those

for white girls age 12-17 years in 25 of the 31

hand-wrist bones, the exceptions being the capitate, trapezoid, metacarpal V, pisiform, and distal phalanges IV and V. Across the age range in

the present study the pattern of racial differences in bone-specific skeletal maturity among

girls is nearly as consistent as that in boys, but

the reverse in direction, and the exception

among girls occurs at age 14 years. At each year

of chronological age except 14 years, the mean

skeletal age for 20 or more of the 31 bones in

Negro girls exceeds that in white girls. At age 14

years, white girls are more advanced skeletally

than Negro girls are for 27 of the 31 hand-wrist

bones.

Previous studies. –There are few reports with

which the present findings can be compared. In

26
the national survey of children (Cycle 11),3 it

was shown that, within a sex, there are statistically significant differences between whites and

Negroes (Negroes more mature) in the skeletal

ages assigned to the radius, ulna, carpak, and

metacarpal in each sex, and to distal phalanges

III-V in boys. In the national survey data for age

12-17 years, the sex differences (femaIe equivalent ages for the girls) were small,l as they had

been during the 6-1 l-year period in the earlier

national survey.2

Ma.Iina and his group86~53 reported TannerWhitehouse skeletal age scores for individual

bones in a group of white and Negro Philadelphia youths age 12 and 13 years. These bonespecific scores cannot be converted to skeletal

ages, but they can be used to compare the

maturation levels in white and Negro youths of

the same sex. In the boys, most bones were

more mature in Negro than in white youths at

both 12 and 13 years, but the reverse was noted

for the scaphoid, trapezium, trapezoid, metacarpal I, proximal phalanx V, and distal phalanges III and V. Without exception, all the

hand-wrist bones tended to be more advanced in

Negro girls than in white girls at both 12 and 13

years. However, in each sex almost all the mean

di f f ere rices between matching bone-specific

scores in these two racial groups were small.

Geographic Region

There is no consistent pattern of regional

differences in the levels of skeletal maturity

among the 31 hand-wrist bones (table 10).

Among boys the most frequent regional patterns

in mean bone-specific skeletal ages were either

slightly higher mean levels in the South and

lower levels in the Northeast than elsewhere (12

of the 31 bones) or slightly higher levels in the

West and lower levels in the Midwest than elsewhere (8 of the 31 bones). For girls the two

more frequent patterns were slightly higher

mean values for those in the Northeast and

lower values in the West than elsewhere (14 of

the 31 bones); and slightly higher mean values in

the Northeast ‘and lower in the Midwest than

elsewhere (9 of the 31 bones). Within bones,

there is no consistency between the sexes in

these small regional differences.

Family Income

There is a clear lack of any strong relationship between skeletal age (hand-wrist) of youths

and family income in the levels of skeletal

maturity for the 31 individual bones (table 11).

Among boys age 12-17 years, the highest mean

skeletal ages for 20 of the 31 bones were among

those boys in the highest annual income level

families ($10,000 or more). However, the lowest

mean wdues for these bones were as nearly common among boys in the lowest annual income

bracket of under $5,000 (12 bones) as among

the middle income group of $5,000-$9,999 (17

bones).

Similarly, among girls age 12-17 years, the

highest mean values for 27 of the 31 hand-wrist

bones were found among those in the bracket of

$10,000 and over but the lowest mean skeletal

ages were much more likely to occur among girls

in the middle income group (21 of the 31 bones)

than in the lower income level (5 of the 31

bones).

Range of Bone-Specific

Skeletal Ages

Commonly, and indeed almost universally,

there are differences among the maturity levels

of the hand-wrist bones within a single radiograph.57 If this were not the case the range

would, of course, be equal to zero. While it has

been claimed that these ranges are greater in

children who are skeletally retarded,58 curiously

there have been few studies of the ranges and,

until recently,1 ~Z reference data were not available.

It has been claimedsSJ59 that a wide range

of bone-specific skeletal ages within a hand-wrist

reduces the reliabilityy of assessments. This does

occur when overall assessments are made, but

there has been some doubt as to whether this

factor still operates when bone-specific assessments are made.60 This variation among skeletal

ages of hand-wrist bones gives rise to problems

of interpretation. Using the atlas method of

Greulich and Pyle, the same mean skeletal age

may be assigned to two hand-wrist radiographs,

although in one the carpals may be more mature

than the other bones are and in the second radiograph the carpals may be less mature than the

27
other bones are. In fact, there is always uncertainty about the skeletal age equivalents of all

radiographs in which unusual patterns of skeletal

maturity levels are present due to the lack of

adequate standardizing samples with the same

patterns.61

Many earlier workers have claimed that illness or malnutrition has differential effects on

the ages of onset of ossification or rates of later

maturation among individual bones.10 Y6* ‘T 0 If

this were established, and if there were no

“catchup” maturation, the range of bonespecific skeletal ages within a hand-wrist radiograph would be a sensitive indicator of past environmental effects.

Findings from the present national survey

with respect to the consistency and variability of

the range of bone-specific skeletal ages, within

individual radiographs, have been analyzed

across racial, re~onal, and family income level

subgroups among youths in the United States of

chronological age 12-17 years. As do the comparable findings among U.S. children age 6-11

years from the preceding national survey,3 these

provide reference data that can be used to assess

the possible effects of such factors as illness or

malnutrition on skeletal maturation. Medians

and quartile points in the distributions of the

range of bone-specific skeletal ages within individual hand-wrists by race, geographic region,

and family income are included in tables 12-14.

Race. –Among white youths age 12-17 years,

the median range in these bone-specific skeletal

ages decreases with advancing chronological age

somewhat more rapidly in girls than boys (table

12). The median values for boys exceed those

for girls at each chronological age. Toward the

end of the range, this would be expected,

because girls characteristically reach adult levels

earlier than do boys and as a consequence there

would be fewer bones in the girls to which skeletal ages could be assigned. For white boys the

median range decreases from 15.9 months at age

12 years to 4.9 months at age 17 years; while for

white girls the decrease is from 14.4 months at

age 12 years to 1.7 months at age 17 years.

Although the median values are higher for the

boys, the variability in these skeletal age ranges,

as measured by the difference between the 25th

and 75th percentiles in their distributions, is

generally less among white boys than among

white girls. Exceptions occur at age 12, where

the values are nearly identical (8. 1 months for

white boys and 8.0 months for white girls) and

at age 16, where values for white girls are the

less variable (1 1.2 months for white boys and

9.6 months for white girls). The younger white

boys age 12-15 years show less variability (.P7~ -

Pz ~ of 8-9 months) than the older white boys of

16 and 17 years (P75 - P25 of about 11

months); among white girls the variabilityy

increases from a minimum at age 12 (P7 ~ - P2 ~

of 8 months) to a maximum at age 15 years

(P75 - P25 of 15.4 months).

As among white youths, the median ranges

of bone-specific skeletal ages within individual

hand-wrists for Negro youths decrease with

advancing chronological age and somewhat more

rapidIy in Negro girls than boys. The median

values for Negro boys exceed those for Negro

girls throughout the age range 12-17 years. For

Negro boys the median range of bone-specific

skeletal ages within the hand-wrist decreases

from 15.0 months at age 12 years to 8.4 months

at age 17 years; among Negro girls the decrease

is from medians of about 12 months at 12 and

13 years (1 1.6 months and 12.5 months, respectively) to 2.7 months at age 17 years. The variability in these skeletal age ranges, as measured

by the difference between the 25th and 75th

percentile in their distributions, is less among

Negro boys than among girls at age 12-16 years

and is somewhat less among younger (age 12-15

years) than among older (age 16-17 years) Negro

boys. The pattern of variability across chronological age among Negro girls is slightly less consistent than that for Negro boys.

There is no consistent racial difference

between white and Negro youths in these ranges

of skeletal maturity. Median ranges for white

and Negro boys differ by only negligible

amounts (1 month or less except at age 17

years) across the age range and not consistently

in one direction; among girls the median values

for white girls at ages 12-15 years are slightly

greater than those for Negro girls. When variability is judged from the difference between 75th

and 25th percentiles, both white and Negro boys

at ages 12-15 years are less variable in skeletal

maturity than their older counterparts; the pattern of variability is less consistent among both

white and Negro girls. There are no marked dif28
fcrences in the variability of these ranges when

youths are separated on the basis of race within

a sex.

Geographic region. –No significant pattern

of geographical regional differences is evident in

the range of bone-specific skeletal ages within

the hand-wrists of youths in the United States

(table 13). Among boys, the geographic regional

median values in these ranges decrease consistently with advancing chronological age from

15-16 months at age 12 years to 4-6 months at

age 17; among girls the medians decrease from

13-15 months at 12 years to 1-4 months at age

17 years. Although the differences between

regions are generally small, there is a slight tendency for the median ranges to be larger in the

West for boys and in the Northeast for older

girls. Furthermore, there is a slight tendency for

the variability of these ranges in the girls to be

greater in the Northeast; but a similar tendency

is not apparent in the data for the boys.

Socioeconomic factors. –Possible socioeconomic influences on the range of bone-specific

skeletal ages within individuals in the youths’

age range were analyzed in relation to family

income. There is no consistent pattern of

income-level differences in the ranges of bonespecific skeletal ages for boys or girls age 12-17

years (table 14). Within each of three broad

income groups, there is a fairly consistent and

similar pattern of decrease in these ranges with

advancing age. Among boys, the decrease in the

median values is from 15-16 months at age 12

years to 4-7 months at age 17 years; among girls

the decrease is from 13-15 months at age 12 to

1-5 months at age 17 years. Among girls, but not

boys, the median ranges tend to be slightly

larger for those with family incomes of

$5,000-$9,999 per year than for the groups with

either larger or smaller incomes. This result

would be puzzling were it not that the differences between these income groups of girls in

their median ranges of bone-specific skeletal ages

were generally small.

ONSET OF OSSIFICATION FINDINGS

During the age range of youths, 12-17 years,

ossification usually begins in two hand-wrist

bones–the adductor and flexor sesamoids in

boys and the flexor sesamoid in girls.

Race

Among white boys in the United States, the

median age of onset of ossification in the adductor sesamoid is 12.4 years, somewhat earIier

than that for Negro boys (12.7 years). The

median age of onset for the flexor sesamoid is

more than a year Iater but shows about the same

racial difference, and in the same direction, 14.2

years in white boys and 14.5 years in Negro

boys (tabIe 15). The median age of onset of ossification for the flexor sesamoid in girls is about

1 year earlier than in boys and is about the same

in white as Negro girls–13.O years and 13.1

years, respectively.

Geographic Region

Across all four regions into which the United

States was divided for the purposes of this survey, the median age of onset of ossification for

the adductor sesarnoid in boys is 12.5 years. For

the flexor sesarnoid the median age of onset in

boys ranges from a low of 13.3 years in the

Midwest to 14.4 years in the South and West.

Among girls there is essentially no geographic

regional difference in the median age of onset of

ossification—1 3.1 years in the Northeast and

13.0 years in each of the other three regions.

Family Income

Among boys (table 15), the median age of

onset of ossification for the adductor sesamoid

is negligibly lower for those in the middle

income bracket of $5,000-$9,999 per year (12.4

years) than in either the lower or higher income

level groups (12.5 years for both those with less

than $5,000 and those with $10,000 or more

family incomes). The onset of ossification for

the flexor sesamoid is delayed in boys from the

family income group of under $5,000 per year

(14.4 years); it is about 1 year later than the

median age for the onset of ossification of this

bone in boys in the yearly income levels of

$5,000 or more. The median age of onset for the

flexor sesamoid in girls shows a consistent but

negligible association with family income. The

median age for those girls in families with less

29
than $5,000 annual income is 13.1 years and is

12.9 years at the income level of $10,000 or

more per year.

Previous studies. –Reported modal ages for

the onset of ossification in the adductor sesamoid in United States boys and the flexor sesamoid in both boys and girls are included in table

H. The data in this table are based on two types

of modal ages: the median or mean age at onset

of ossification and the age when the center was

ossified in 50 percent of the youths. The latter

estimate was obtained after plotting the percents, at successive chronological ages, on probability paper. The youths included in these samples were predominantly of northwestern European ancestry and of middle, or slightly above

middle, socioeconomic status.

The report of Harding71 was based on

mixed longitudinal data from white youths in

Boston born between 1930 and 1939 and examined near each birthday. The sample size

varied from 40 to 60 at each age in each sex.

The data of Greulich and Pylel 0 and Pyle et

aLTs were obtained from serial radiographs, by

interpolation, on the thesis that onset of ossification occurred between the age at which the

center was first visible radiographically and the

age at which the last radiograph was taken in

which the center was not visible radiographically. The interpolated ages were not necessarily

midway between the ages at which these two

annual radiographs were taken. However, it is

reasonable to assume that the recorded ages

were systematically 0.5 year earlier than would

have been recorded had these authors applied

the more familiar method of recording the age at

which the center was first observed. Consequently, to make these findings more comparable, in methodology, with those reported by

others, 0.5 year has been added to each modal

age reported by Greulich and Pylel 0 and Pyle et

al.Ts before it was included in table H. Greulich

and Pylel 0 analyzed data from serial radiographs of 100 boys and 100 girls in the Brush

Foundation study. These were white youths of

upper socioeconomic class living in Cleveland,

Ohio, who had been born between 1917 and

1930. Data from the serial study at the Department of Maternal and Child Health at Harvard

University were reported by Pyle et al.T3 These

youths (16 boys, 14 girls with relevant data)

were white and middle-class socioeconomically,

and were living in or near Boston, Massachusetts,

having been born between 1930 and 1939. The

youths whose data were reported by Pyle et

aL73 were included also in the group studied by

Harding.71

The data of Buehl and Pyle64 were obtained

from a subset of Brush Foundation youths (30

boys). It is not clear whether these authors interpolated ages at ossification in the manner of

Greulich and Pylel 0 and Pyle et al. ;T3 consequently the reported ages have not been adjusted.

Mixed longitudinal data derived from middle

socioeconomic class white youths in southwestern Ohio who were born between 1929 and

1960 were reported by Garn et a.1.7z These

youths were radiographed within 1 month of

each birthday and half-birthday. The sample size

was about 180 for each sex in each 6-month

interval.

Table H. Modal ages (years) for onset of ossification in selected bones in U,S. white youths

Bone and sex

BOYS

Adductor sesamoid ...............................................................................

Flexor sesamoid ....................................................................................

Girls

Adductor sesamoid ...............................................................................

Flexor sesamoid ....................................................................................

12.164

13.510

10.5’34

11.01’J

Modal age from previous studies

12.673

10.772

12.771

10.810

12.872

11.073

13.210

11.274

United

States,

1966-1970

12.5

14.2

10.7

13.0

30
Hansman74 studied about 50 white boys

and 50 white girls of middle socioeconomic

status who were enrolled in the program of the

Child Research Council, Denver, Colorado.

These youths were born between 1915 and

19540

There is very close agreement between the

ages reported by Pyle et aL,73 Harding,7I and

Garn et aL7z for the onset of ossification of the

adductor sesamoid in boys. It is surprising, however, that both the earliest and the latest ages

have been reported from the Brush Foundation.64 )73 In part, this may be methodological.

As noted earlier, Buehl and Pyle may have interpolated, in which case 0.5 year should be added

to the ages reported by them. The median age

for white boys in the national survey is at about

the midpoint of the range of modal ages reported by others. In both boys and girls, the

flexor sesamoid began to ossify just slightly later

in the national survey youths than in the group

of youths studied by Greulich and Pyle.1 OThese

authors have provided the only other set of data

on age of onset of ossification for the flexor

sesamoid of youths in the United States.

In reviewing data for youths of European

ancestry living outside the United States,

emphasis will be placed on those countries from

which large numbers of immigrants have come

to the United States. Joseph’5 reported data

concerning the onset of ossification in the

adductor sesamoid for English youths living in

London, but the sample size and the method of

reporting do not allow useful comparisons

between his conclusions and those of the present

national survey. Semp&76 reported median ages

for the onset of ossification of the adductor sesamoid and flexor sesarnoid in French youths (91

boys, 89 girls) generally of middle socioeconomic status living in Paris (table J). These

youths were born in 1953 and radiographed

close to birthdays and half-birthdays. Rudzinski’ 7 reported modal ages for the onset of ossification of the adductor and flexor sesamoids

based on mixed longitudhml data from 6-month

radiographs of 91 Polish boys in Warsaw. These

ages for youths in Paris or Warsaw are slightly

later than the estimates for U.S. white youths in

the present national survey (table J), with the

exception of the flexor sesarnoid in girls. It is

Table J. Modal ages (years) for onset of ossification in youths of

European ancestry living in Europa

I Modal age

Bone and sex I

197076

I I

Boys

Adductor sesamoid ................................

I

13.0 13.0

Flexor sesamoid .................................... 14.0 13.5

Girls I I

Flexor sesamoid .................................... 1 12.01 ---

NOTE: Semp&French youths in Paris; Rudzinski–Polish

youths in Warsaw.

stressed, however, that all these differences are

small.

Comparisons can be made between reported

modal ages for the onset of ossification in some

hand-wrist centers in Negro youths living in the

United States and Negro youths living in Africa.

The differences are not easily interpreted because it is impossible to identify groups of Negro

youths in the United States or Africa that

belong to the same relatively homogeneous

genetic pool. The data considered for Negro

youths in Africa relate to the part of Africa

from which large numbers of slaves were transported to the United States,7s ~’g but, almost

certainly, the present U.S. Negro population is

unrepresentative of the original slaves and the

slaves were unrepresentative of the African populations from which they were taken.

Michaut-Barthod80 reported data from 628

radiographs of Ovoloff youths of low socioeconomic status living in Dakar (Senegal). Most of

these youths were radiographed three times near

birthdays or half-birthdays. About 40 radiographs were available for each sex at each

6-month interval. Although all the youths were

more than 11 years of age at the time of their

first radiograph, the data are useful for comparative purposes. Masse and Hunts 1 reported crosssectional data from children of Ovoloff ethnic

origin living in Dakar. The sample included 45 to

95 children of each sex in both age groups. The

data of Michaut-Barthod80 and Masse and

Hunt8I make it clear that the onset of ossification tends to occur considerably earlier in U.S.

31
Negro girls than in African Negro girls they

studied, but the corresponding differences are

smaller for boys.

Sutow42 reported data from normal Japanese youths of all socioeconomic levels in Hiroshima. The sample size for each sex varied from

67 to 104 for each year of age. The ages at onset

of ossification that he reported (boys: pisiform

12.3 years, adductor sesamoid, 14.0; girls:

adductor sesamoid, 11.8 years) are considerably

later than those found in Cycles 112 and 1111of

the Health Examination Survey. As pointed out

earlier in this report, it is likely that the current

ages of onset of ossification in Japanese youths

are much closer to those of youths in the United

States.

EPIPHYSEAL FUSION

The national survey data were used to estimate median ages at epiphyseal fusion by interpolating between prevalence data for annual age

groups. This allowed reasonably accurate estimates for all relevant bones except the radius in

each sex and the ulna in the boys. The order of

median ages was closely similar in each sex and

in both white and Negro youths. Fusion tends to

occur earlier in white boys than in Negro boys

(table 16). For about half the bones (metacarpal

I, proximal phalanges I-V, and middle phalanges

II-V) these bone-specific differences are statistically significant at the 5-percent level. The

bone-specific racial differences in median ages at

epiphyseal fusion are less consistent in the girls.

About half these median ages are earlier in white

girls than in Negro girls; and nearly half are

earlier in Negro than in white girls. Fusion

occurs significantly (5-percent level) earlier in

white girls than in Negro girls for metacarpal I,

proximal phalanges I-V, and middle phalanges

II-V. An opposite tendency, also significant at

the 5-percent level, is present, however, for the

ulna; metacarpal II-V; and distal pha.IangesI, II,

and IV.

Table K. Modal aoesfor e~i~hyseal fusion in the hand-wrist of U.S. white youths

Hand-wrist bone

Radius .......................................................................................

Ulna ..........................................................................................

Metacarpal I ..............................................................................

Metacarpal II .............................................................................

Metacarpal 111............................................................................

Metacarpal lV ............................................................................

Metacarpal V .............................................................................

Proximal phalanx I ....................................................................

Proximal phalanx 11...................................................................

Proximal phalanx III .................................................................

Proximal phalanx IV .................................................................

Proximal phalanx V ...................................................................

Middle phalanx II ......................................................................

Middle phalanx Ill .....................................................................

Middle phalanx lV .....................................................................

Middle phalanx V ......................................................................

Distal phalanx I .........................................................................

Distal phalanx 11........................................................................

Distal phalanx III ....................................................................!.

Distal phalanx IV ......................................................................

Distal phalanx V ........................................................................

Boys

18.074

17.874

16.374’82

16.4,s2 16.574

16.4,a2 16.574

‘16.474Va2

16.574’s2

16.2,73*74 16.3a2

16.3,a2 16.474

16.2,73 16.374*S2

16.2,a2 16.574

16.274’82

16.474*a2

16.4,8216.574

16.474*82

16.3,74 16.4s2

15.7,= 15.974

15.7,7315.8,74 16.0a2

16.074*82

15.8,74 16.0a2

15.9,74 16.0a2

Modal age

15.874

15.974

14.1 ‘4$2

14.5,74 14.6s2

14.5,74 14.6s2

14.4,7414.682

14,4,7415.082

14.2,7414.3,73 14.4a2

14.274Sa2

14.2,74 14.5s2

~4.274,a2

14.274*82

14.274S82

14.4,74 14.5*2

14.3,741 4.5=’

14.2,7414.382

13.5,a2 13.674

‘12.5,64 ~3.6,74’a2 13.773

13.6741s2

13.674@2

73.674,52

. . .

. . .

15.8

16.5

16.6

16.6

16.6

16.3

15.9

16.1

16.1

15.8

16.1

16.3

16.3

16.3

15.7

15.8

15.8

15.6

15.7

. . .

16.2

13.8

14.8

14.8

14.9

15.0

14.0

14.0

14.1

14,1

14,0

1349

14.1

14,1

14.0

13.5

13.5

13,5

13.4

13.4

32
Previous Studies

Data from other studies of white youths

living in the United States are included in table

K. There are no previously reported data for

Negro youths in the United States. Hansman74

reported data on Denver, Colorado, youths of

above average socioeconomic status who were

mdiographed at 6-month intervals. These youths

(about 30 of each sex) were born between 1915

and 1941.

Data from a small group (IV= about 12 for

each bone in each sex) of Boston youths have

been reported by Pyle et a.1.73 These middle

class youths who were born between 1930 and

1939 were radiographed annually. In interpreting these data, it is important to recall that the

relatively late-maturing males are underrepresented because the study was discontinued

before all had matured.

Buehl and Pyle64 reported data from 30

boys and 30 girk of upper socioeconomic status

enrolled in The Brush Foundation Study, Cleveland, Ohio, who were examined serially. Findings from 107 youths in southwestern Ohio who

were slightly above average socioeconomically

havt been reported by Garn et al.g Z In all these

studies, as in the national survey, epiphyseal

fusion was considered to be present when the

epiphyseal cartilage had been completely replaced, even if a radio-opaque line persisted at

the junction.

In general, the national survey estimates are

close to those reported for these smaller, less

representative groups; the match is particularly

close for girls. The median ages for boys from

the national survey are earlier than those in the

previous reports for metacarpal I, proximal

phalanges II and V, middle phalanx II, and distal

phalanges IV and V. In girls, the national survey

ages are earlier than those reported previously

for middle phalanges III and IV and later for

metacarpal IV.

There are few sets of satisfactory data

reported for youths living abroad. Ages at which

cpiphyseal fusion occurred, using cross-sectional

data from 1,613 Japanese children and adolescents, have been reported by Russell et al.s 3

Although the subjects had been in utero in Hiroshima or Nagasaki at the time of the atomic

bombing, there was no evidence that the age of

Table L. Reported ages of ep:

Hand-wrist bone

Radius ....................................

Ulna .......................................

Metacarpal I ... ............ ............

Metacarpal II ..........................

Metacarpal Ill .........................

Metacarpal IV .........................

Metacarpal V ..........................

Proximal phalanx 1.................

Proximal phalanx I l ................

Proximal phalanx Ill ..............

Proximal phalanx IV ..............

Proximal phalanx V ................

MiddIe phalanx I I ...................

Middle phalanx I I I ..................

Middle phalanx IV ..................

Middle phalanx V ...................

Distal phalanx 1......................

Distal phalanx I l .....................

Distal phalanx Ill ...................

Distal phalanx IV ...................

Distal phalanx V .....................

lvseal fusion in

Russall et al.,

1973’33

Boys

18.75

18.25

16.25

16.75

16.75

17.0

17.0

16.75

16.75

16.75

16.75

16.75

16.75

17.0

17.0

16.75

16.0

16.25

16.25

16.5

16.5

Girls

17.75

17.25

14.75

15.50

15.25

15.5

15.75

15.25

15.0

15.0

15.25

15.0

15.25

15.5

15.5

15.0

14.5

14.5

14.5

14.75

14.5

]anese youths

Sutow

19534$

Boys

18.8

IB.7

. . .

---

..-

..-

---

. . .

. . .

---

.-.

---

. . .

..-

. . .

---

16.3

---

-..

---

17.5

17.3

..-

-..

---

-..

---

---

-..

..-

. . .

. . .

-..

---

. . .

. . .

14.5

. . .

. . .

. . .

closure was related to the estimated radiation

exposure dose. The ages reported by Russell et

al.s 3 indicate that fusion occurred about 7

months later than in U.S. youths (table L).

These findings are in general agreement with

those of other workers who have studied groups

of Japanese youths.4 Z74s *84

Median ages at fusion in the third proximal,

middle, and distal phalanges of Danish boys are

very similar to those estimated from the United

States National Survey.85

DISCUSSION

There is no doubt that youths of different

racial groups vary in body size and in levels of

skeletal maturation and sexual maturity at corresponding chronological ages.86 ‘g 1 The factors

that control the rate of skeletal maturation must

act by influencing the formation or resorption

of bone. The possible factors are related to

genes, nutrition, illness, and climate, inter alia,

but few studies have been designed so as to sep33
arate the possible effects of these factors. Consequently, knowledge is almost entirely lacking

concerning the effects of relatively precise environmental factors (e.g., protein intake, temperature), on rates of skeletal maturation in youths

or of specific groups of genes (e.g., autosomal,

sex-linked).

This discussion will relate to the factors considered in this report (race, geographic region,

size and type of community, family income,

parental education) that could have been associated with real population differences in skeletal

maturity levels. The findings from the present

survey will be discussed in relation to the findings from the corresponding study of children

age 6-11 yearss and in relation to reports based

on findings from smalIer less representative

groups. In interpreting these findings, it should

be recalled that the national surveys are the only

source for national estimates of skeletal maturity levels. The sarnpling technique employed

ensured that a truly representative sample was

chosen for each survey. Of the children chosen,

96 percent were examined; the corresponding

figure for the youths is 90 percent. Consequently, these national surveys can provide reasonably reliable estimates for the entire U.S.

population of children and youths.

Race

It is difficult to interpret racizd comparisons

because, almost always, the groups compared

differ not only genetically but in environmental

factors, particularly in nutrition and the incidence of disease. The importance of genetic factors is clear from studies of the timing and pattern of onset of ossification and the occurrence

of skeIetal variants (e.g., pseudoepiphyses)

in pairs or triads of individual sharing similar

environments but different proportions of

genes.65)92-111 These studies indicate that

the extent of the differences within pairs or

triads are approximately inversely related to the

percentage of genes shared in common.

Skeletal age (hand-wrist). –The two national

surveys show that Negro boys tend to be more

mature skeletally than white boys at 6-9, 11,

and 13 years, but the reverse is true at the other

ages. White girIs, however, are less mature skeletally than Negro girls throughout the whole age

range except at age 16-17 years. There are no

consistent white-Negro differences in the variability of skeletal age. These findings indicate

possible changes with age in racial differences

(white-Negro) relating to skeletal maturation in

boys and girls, but the patterns vary between the

two sexes. Soon after birth, centers of ossification are more numerous in newly born Negroes

than in whites; this is true for Negroes living in

Africa as well as for those living in the United

States. This acceleration in Negroes occurs

despite their generally less favorable socioeconomic circumstances.1 11’1 ‘ 5 This advancement

of Negroes in onset of ossification has been

reported up to about 7 years of age.1 1G~11T

However, as noted earlier in the national surveys, Negro youths were more advanced in skeletal maturation than white youths only until age

13 years (and then not at all ages) in boys and

‘ until 16-17 years in girls. Age-related patterns of

racial differences in skeletal maturity have been

noted by Lee et all 18 These workers reported

that Chinese children in Hong Kong were

advanced in onset of ossification over U.S. children when early-appearing hand-wrist centers

were considered, but an opposite tendency was

present for late-appearing centers.

In the national survey data there are only

slight differences between the mean values for

skeletal age in Negro and white youths within

each sex. The small size of these differences and

their inconsistency across age and sex are in

agreement with reports by Toddz4 and

Malinas ~‘s 5 and MaIina et al.~ G that whiteNegro differences are inconsequential during the

age range 12-17 years. The substantial acceleration of skeletal maturation in U.S. Negroes compared with those in Jamaica or Dakars TIS8 presumably reflects environmental effects.

Previous studies of groups of white U.S.

boys10,16-19,21-23 are not in complete agreement with the national survey findings that the

mean skeletal ages of U.S. white boys are considerably less than the mean chronological ages at

9-12 years. While Flory,l G Todd,l 8 and

Mareshz 2 reported low mean skeletal ages during this age range, the patterns of change with

age in their data differed from those in the

natiomd sample. It must be stressed that these

earlier studies were of less representative groups

of youths in the United States, and most of the

34
studies were not based on bone-specific skeletal

ages. A further factor to be considered is the

level of reliability of assessments of skeletal

maturity.

The natiomd survey data for white girls

(female equivalent values) are generally similar

to those for boys with two exceptions: the retardation of the mean skeletal ages from 9 to 12

years is less marked, and there is a marked and

rapid retardation after 15 years. The data of

Floryl 6 indicate an even greater skeletal retardation of girls at 9-12 years, but the early literature contains no hint of the change in reIative

leveI after 15 years that is so marked in the

national survey data. As discussed earlier,l this

is almost certainly due to the fact that all the

national survey radiographs were assessed, without identification by sex, against a single set of

male standards. Later the values for girls were

transformed to female equivalent values using a

set of sex-associated differences in skeletal age

provided by Dr. S. Idell Pyle. These sex differences were derived by Dr. Pyle after a painstaking stud y of radiographs.g However, to take the

extreme example, the means of the skeletal ages

assigned to boys and girls age 17 years on the

male standards differed by ordy 5.9 months,

whereas the difference of 22 months as reported

by Pyle et al.g was used in the transformation.

The actual sex difference on the male standards

was greater than reported in the HES Standardg

at the earlier ages. Its marked reduction at later

ages was due only slightly to the exclusion of

girls in whom all the hand-wrist bones had

become adult.

The previous literature for U.S. youths

would lead one to expect that epiphyseal fusion

would be complete throughout the hand-wrist of

a typicaI girl age 17.5 years, but that fusion

would not have occurred at the distal ends of

the radius and ulna in a typical boy of the same

age.73 !74,82 ALso, these earlier studies Iead to

the expectation that in a majority of the girls

age 17.5 years it would be impossible to assess

the hand-wrist because all the bones of this area

would be adult. In the national survey data this

occurred in 22 percent of the girls. If a skeletal

age of 19.1 years were assi~ed to each of these

girls (19. 1 years is the highest maximum value

for any bone on the male standards) this would

have very little effect on the sex-associated differences in skeletal maturity, as calculated previously. This matter is discussed more fully in

the earlier report.]

There is no evidence of a secular trend in

skeletal maturation rate when the data for white

U.S. children and youths are compared with

reported findings from earlier studies. This is

true whether the comparison is with the sets of

data in figures 1-410>1 G-19,21,22 or with data

reported still earlier from New England children

and youths, 24 percent of whom were of Italian

ancestry.1 1g,1 ZO

It is not easy to interpret the apparent

absence of secular trends when data from the

nationaI surveys are compared with data from

less representative groups-sampling variations

may mask real differences or alternatively any

differences found may be due to sampling variations. These methodological problems can be

overcome only by repeated national surveys, but

it is interesting to note some findings from longterm serial studies of unrepresentative groups in

the United States.

In the group of southwestern Ohio children

and youths studied at the Fels Research Institute, rezd secular trends are not apparent over a

period of 36 years, when skeletaI age is regressed

against year of birth (table M).1 z 1 Similarly, in

the same group, the mean relative differences for

RWT (Roche, Wainer, and Thissen) skeletal ages

between parent-offspring pairs, within sex, are

small and inconsistent in direction (table N).

RWT skeletal ages are obtained from the knee,

but there is no reason to believe that this area is

any less representative of the whole skeleton

than is the hand-wrist.61 These findings show

that little if any secular trend has occurred during recent decades in a group of children and

Table M. Correlation coefficients between skeletal age

(Greulich-Pyle) and year of birth in the Fels Longitudinal

Study (Roche, unpublished data)

Boys Girls

Chronological age

N r N r

3 years................................... 112 -0.016 118 +0.1 87

6 years................................... 120 -0.088 105 +0.162

9 years ................................... 91 +0.179 82 +0.185

12 years ................................... 73 –0.01 1 73 +0.705

NOTES: None of these coefficients is significant at the

5-percent leveL

N = number of subjects; r = simple correlation coefficient.

36
Table N. Mean relative differences between parant-offspring

pairs in skeletal age (RWT, knee in years)

Chronological age

6 years ....... ........... .

7 years ...................

8 years ...................

9 years ...................

10 years ...................

11 years ...................

12 years ...................

13 years ...................

14 years ...................

15 years ...................

16 years ...................

Difference

Father-son

—

N

—

25

24

23

25

21

17

14

8

9

8

8

—

Mean

-.33

-.15

+.40

+.29

+.1 2

+.16

+.24

+.04

+.17

-.93

-.02

Sx

1.16

1.36

1.14

1.32

1.45

1.32

1.89

1.36

0.75

0.59

0.51

Motherdaughter —

N

—

33

35

32

29

19

20

21

17

17

19

10

— I

Mean Sx

-.16 1.17

+.21 1.10

+.23 1.40

+.08 1.35

-.35 1.28

-.95 1.52

-.14 1.00

-.15 0.98

-.32 1.15

-.62 1.71

-.57 1.48

NOTE: + = rmrent more mature; N = number; s. =

standard deviation.

.

youths of middle socioeconomic status when

effects of sampling variability are largely removed. These findings are in close agreement

with those of Mareshl 2 Z who reported data

from a middIe socioeconomic group in Denver,

Colorado. Taken together, these studies suggest

that secular trends in skeletal maturation rates

are absent or very slight in white U.S. children

and youths of middle socioeconomic status. Of

course, due to the method of group selection,

these findings cannot be extended to all socioeconomic levels and geographic regions as the

national survey data can for youths in the

United States.

The tentative conclusion that secular

changes in the rates of skeletal maturation may

no longer be occurring in the U.S. population

shouId be considered in reIation to secular

changes in body size. After a close analysis of

data recorded in national probability samples

between 1962 and 1974,90 S1239124 it was concluded there was no evidence of a secular trend

in either stature or weight during this period

except for a slight change at the lower percentiles. Thus the data for body size are in agreement with the tentative conclusion that has been

reached in regard to skeletal maturation.

Variability. –The national survey findings

concerning possible white-Negro differences in

the variability of skeletal age are inconsistent

suggesting that , if such differences do occur,

they must be small. In each of these racial

groups skeletaI age was more variable for the

boys than for the girIs. This is in agreement with

earIier reports.1 6J19Y38Y39Y5z Presumably it is

due, at least in part, to truncation of the distributions for girls as they approach the upper

limit of the skeIetal maturity scaIe.

Bone-specific skeletal ages. –The national

survey data show that, among boys 12-17 years,

the mean skeletal age of each hand-wrist bone is

more advanced in the whites than in the Negroes, although the individual differences are not

large enough to be statistically significant. There !

is an opposite tendency among girls but this also

is not statistically significant. The directions of

these differences within each sex, at 12-13 years,

match those reported by Malina et a.1.36 and by

Malina.53 As would be expected from the findings for mean skeletal ages, the white-Negro differences in bone-specific skeletal ages are, however, in the reverse direction to those found in

the national survey of children.3 In the earlier

survey, most of the individual hand-wrist bones

were less mature in the whites than in the Negroes.

In the national survey data, there are no consistent white-Negro differences in the mean

ranges of bone-specific skeletal ages or in the

variability of these ranges within individual

hand-wrist radiographs. In both Negro and white

groups, the means of the bone-specific skeletal

ages are less variable in boys than girls, but the

range of bone-specific skeletal ages is greater in

boys than in girIs.

Onset of ossification. –Only for the adductor

and flexor sesamoids in boys and the flexor sesamoid in girls do the modal ages of onset of ossification occur during the age range of the present survey (12-1 7 years). White boys are very

slightly advanced over Negro boys in median

ages for the onset of ossification in these bones

(0.3 year); the corresponding difference for the

flexor sesamoid in girls is trivial (0.1 year).

These findings are consistent with the small, statistically nonsignificant white-Negro differences

in mean skeletal age and bone-specific skeletal

ages. The national survey data are close to those

reported for other groups of white youths in the

United States except for the flexor sesamoid in

boys. The only previous estimate for this

bonel 0 is considerably earlier. There are no pre36
vious estimates for Negro youths in the United

States.

Epiphyseal fusion. –The national survey data

allow estimates for the median ages at epiphyseal fusion for all hand-wrist bones that develop

epiphyses except the radius in both boys and

girls and the ulna in boys only. In the latter

bones, the median ages are too late for them to

be estimated accurately from the present data.

There is no evidence of a racial difference in the

sequence of fusion, but fusion tends to occur

earlier in white boys than in Negro boys. This

would be expected from the racial differences in

skeletal maturity levels for boys. Both in girls

and in boys there is a consistent pattern of statistically significant differences in ages at epiphyseal fusion between white and Negro youths

(metacarpal I, proximal phalanges I-V, and

middle phalanges II-V); these ages are earlier in

whites than in Negroes. There is a significant

racial difference in the opposite direction in girls

for the ulna, rnetacarpals II-V, and distal phalanges I, II, and IV. This is in agreement with the

finding that white girls are less advanced skeletally than Negro girls at 12-15 years although

the reverse is true at 16-17 years. The estimated

ages at fusion for white boys and girls are very

similar to those reported by others for smaller

groups of U.S. youths;G4~T3Y74Y8z there are no

comparable data for Negroes in the United

States.

Geographic Region

Very few studies of regional factors allow

the separation of genetic and specific environmental effects. Regional differences, within the

United States, in the incidence of illness, based

on the same regions considered here, will be provided in later NCHS reports. Regional differences in nutritional status have been reported

from the Ten-State Nutritional Survey,l zs and

anthropometric differences have been reported

in a previous NCHS report.124

An earlier report3 provides estimates of

regional differences in the skeletal ages of U.S.

children 6-11 years. After removal of the effects

of age differences and varying racial distributions among regions, there was a tendency for

U.S. children in the Northeast and Midwest

Regions to be slightly advanced in skeletal

maturity compared with those in the other

regions. However, most of these regional differences relating to children age 6-11 years could

have been due to chance.

The data for U.S. youths (boys and girls)

from the present survey reveal only small regional differences after age-related and racerelated effects are removed. Those in the South

are slightly more advanced skeletally and those

in the Midwest slightly less advanced than those

in the Northeast and West, but these differences

were not statistically significant. Sampling variability could have been responsible for the variation between this pattern for youths and that

reported previously for children.s If the skeletal

maturity of U.S. youths indeed differs by geographic region, this was obscured by the large

heterogeneous regions into which the United

States was divided when the national survey data

were analyzed.

If real differences between geographic

regions had been found, it could have been postulated that climatic factors were responsible.

Despite suggestions, there is no convincing evidence that tropical climates retard skeletal

maturation,l z6~1z T although it does appear that

warm climates retard age of menarche. 1z8 There

are severe difficulties in interpreting the reported data because there has not been control

of many confounding variables in the study

design or the statistical analysis. While heat promotes calcification experimentally,l z9~130 this

is doubtfully relevant. Studies of experimental

animals in extreme environmental temperatures 18*13l‘133 suggest that heat accelerates

skeletal maturation, but large ambient temperature differences between the control and experimental groups are needed to p~oduce this effect.

If -significant differences had been found

between the skeletal maturity of groups of

youths separated by geographic region, it would

have been difficult to associate these differences

with climate. The fact that significant differences were not found may reflect the diversity

of these large regions and, perhaps, migration

between them. If the aim had been to demonstrate the existence of regional differences, a

more appropriate sampling (e.g., of those living

at high altitudes, in the desert, or in the arctic

region) would have been employed. However

interesting, such a study would be less important

37
in relation to public health within the United

States than the present estimates forverykirge

groups.

Bone-specific skeletal ages. –The differences

between the mean bone-specific skeletal ages for

groups separated on the basis of geographic

region are inconsistent. This would be expected

from the lack of statistically significant differences between the mean skeletal ages for groups

of youths in the four large geographic regions of

the United States. The mixed pattern of advancement and retardation among the bonespecific skeletal ages for each region is inconsistent for the two sexes. This indicates a lack of

major differences among the regions in their general levels of factors, as an example, nutrition,

known to affect the rate of skeletal maturation.

Similarly, there are only small differences among

the geographic regions in the median ranges of

bone-specific skeletal ages within single radiographs. There is, however, a slight tendency for

the median ranges to be larger for boys in the

West and for older girls in the Northeast.

Onset of ossification. –There were almost no

regional differences in the mean ages of onset of

ossification for either the adductor sesarnoid or

the flexor sesamoid except that the flexor sesamoid in boys ossified somewhat earlier in the

Midwest.

Urban-Rural

There are no consistent urban-rural differences in mean skeletal ages either for youths in

the present national survey or for children in the

previous survey.3 However, among youths but

not among children, there is a slight tendency

for skeletal maturation to be advanced in those

living in large urban areas (population exceeding

3 million). Presumably, the absence of real differences between urban and rural areas reflects

the heterogeneous nature of the environment

within these groupings and the lack of major

urban-rural environmental differences in the

United States, as in the case in Australia.l34

This situation differs sharpIy from that in some

other countries where there are major socioeconomic differences between urban and rural areas

and associated differences in rates of skeletal

maturation and physical growth.l 35-14 Z

Socioeconomic Factors

Skeletal maturation. –The importance of

socioeconomic factors in controlling the rate of

skeletal maturation, as distinct from age at onset

of ossification, has been stressed by several

workers.l 8Y1ss ~14s -14 f’ Particularly important

data have been reported by Low et al.s g who

recorded Greulich-Pyle skeletal ages for a large

group of Hong Kong youths separated into high

(IV = 3,659), middle (N= 5,227), and low

(N= 5,591) socioeconomic groups (table O).

This grouping was made using a combination of

parents’ education, parents’ occupation, total

family income, and housing.8 T Skeletal maturity

level is associated positively with socioeconomic

status in these data, but the mean differences are

small despite the very wide ranges of socioeconomic status among the groups compared. These

comparatively smaIl differences are in agreement

with the observations of Grande CoVi&n and Rof

Carballo.l 4 G

Kopczyfiska3 z reported data from upper

and lower socioeconomic class Polish youths

(total N= 3,988) that show a significant association in the expected direction between socioeconomic status and the level of skeletal maturity.

Because her data were analyzed on the basis of

the percentages of subgroups in whom the

chronological age exceeded the skeletal age,

Table O. Mean skaletal ages for southarn Chinese youths in

Hong Kong at various socioeconomic levels (Low et al.,

1964)39

Chronological age and sex

Boys

12.0 years ............................................

13.0 years ........ ...o................................

14.0 years ............................................

15.0 years ............................................

16.0 years ............................................

17.0 years ...... ......................................

Girls

12.0 years ............................................

13.0 years .............................. ..............

14.0 years ............................................

15.0 years ............................................

16.0 years .... ........ .............. ..................

17.0 years ............................................

Socioeconomic status

High Middle Low

Mean skeletal age

11.5

12.8

13,9

15,3

16.6

17.7

12.3

13.6

14.6

15.5

16.3

17.0

11.1

12.5

13.8

15.1

16.4

17.6

12.1

13.3

14.5

15.4

16.3

17.0

11.1

12.5

13.9

15.0

16.2

17.3

11.8

13.0

14.2

15.3

16.2

17.0

38
direct comparisons cannot be made between

these data and those of Low et aL39 with regard

to the magnitude of socioeconomic effects.

Neyzi et aL147 using data from 2,000 urban

Turkish youths of moderately different socioeconomic levels found only slight associations

with skeletal maturity levels. The differences

were significant only when extreme socioeconomic groups were compared and, even then,

only in the girls. These relatively small or absent

socioeconomic effects on the rate of skeletal

maturation in youths support the contention of

Achesonl48 that the slowing of skeletal maturation with an adverse environment has been

demonstrated with certainty only in the prepubertal period.

The differences among socioeconomic

groups reported by Low et al.39 for Chinese

youths were slightly greater in girls than in boys

up to age 15 years. Later, there was a slight sex

difference in the reverse direction that may have

been due, in part, to some of the girls reaching

the upper limit of the skeletal maturity scale.

This greater effect in girls is in agreement with

the findings of Neyzi et aL147 In Polish youths,

however, the apparent effect of socioeconomic

status on skeletal maturity level is greater in

boys than girls.3z)149

Deschamps and Benchemsil 50 reported

findings from 4,526 French children and youths

examined at ages from 6 to 18 years. The handwrist skeletal ages (Greulich-Pyle) of these children were significantly related to the occupation

of the father (especially in boys), the level of

education of the mother (girls only), the quality

of housing (both sexes), and the number of children in the family; Their data were not analyzed

within age groups: but the authors report that

the differences in skeletal maturity levels with

environmental factors were more marked in adolescents, which is in conflict with the report of

Frisancho et al.l51 Although many of the differences reported by Deschamps and Benc hernsils O were statistically significant, the

mean differences were rather small (3-6 months

of skeletal age), which is in general agreement

with other reports from Belgiuml52‘ *s 3 and

France.1s 4

These variations between studies in sex differences could reflect variations among races in

the sensitivity of skeletal maturation to socioeconomic influences, or differences among races

between the care of boys and girls classified as

being at the same socioeconomic level. These

reports draw attention to the slender and inconsistent evidence on which claims are made that

skeletal maturation is less affected by environmental factors in girls than in boys.

Andersen, in her analysis of data from

Copenhagen children,z 8 reported a marked

association between skeletal maturity level and

the father’s occupation and a lesser association

with family income. There were no real differences in skeletal maturity levels in relation to

employment of the mothers, but crowding of

apartments seems to be associated with skeletal

retardation in lower socioeconomic groups.

When such skeletal retardation occurs, it is

probable that adverse environmental circumstances do not affect all bones equally. Differential effects have been described within the

hand-wrist only. 1ss If they occur throughout

the skeleton, they could lead to differences in

body proportions between upper and lower

socioeconomic groups. That such differences in

proportions are affected by environmentzd influences may be inferred from data relating to the

ratio

sitting height

stature

in Japanese youths, American-born Japanese

youths, and American children.A 0 This inference

is supported also by the marked secular trend in

this ratio. Similarly, a secular trend toward a

more linear build has been noted in Yugoslavia

with improved socioeconomic conditions. 1s 6

In the present national survey, socioeconomic status was categorized by family income

(within wide groupings) and by years of parentzd

education. In the survey data, mean skeletal age

is not related consistently to family income.

Although there is a slight tendency for it to be

slightly more advanced in those with family

incomes exceeding $10,000 per year, the lowest

income group (less than $3,000 per year) were

not the least advanced in either sex. This lack of

a clear-cut relationship is not due to a confounding effect of race. Within racial groups, there is

no consistent relationship between family

income and skeletal maturity. However, within

family income groups, white boys tend to be

39
more mature skeletally than Negro boys for

those in families of moderate or lower income

levels under $10,000 while white girls tend to be

less mature in this respect than Negro girls irrespective of family income level. Similarly, there

are no statistically significant differences in

skeletal maturity between groups separated

according to the length of parental education.

There is also no strong interrelationship

between bone-specific skeletal ages and family

income. While more advanced ages tend to occur

in the upper famiIy income groups, the lowest

ages are almost equally distributed between the

middle and lower family income groups. The differences among the ranges of bone-specific skeletal ages, within single radiographs, for groups of

youths separated by family income are very

small and the pattern of differences is inconsistent.

Onset of ossification. –The modal ages reported from previous studies concerning the

onset of ossification for youths in the United

States of northwestern European ancestry were

derived from middle or slightly superior socioeconomic groups (table B). Those studied by

Harding71 were from average middle class families. Findings from youths described as being

from a good class of English-speaking people

were reported by Baldwin et all57 The data of

Hansman74 were derived from upper-middle

socioeconomic class youths studied by the Child

Research Council, Denver.ls 8 The youths

studied by Floryl 6 were also above average in

economic and in social status. The youths from

whom Garn et al.7 z obtained data were generally of upper-middle socioeconomic status, but

not quite as high as the sample of Hansman.7 *

It is difficult to interpret the variations

among ages at the onset of ossification reported

by these workers in relation to socioeconomic

status. Youths in the groups studied by Hansman74 and Floryl 6 appear to have been of

slightly higher socioeconomic status than youths

in the groups studied by others. If such a difference in socioeconomic status were present, it is

not reflected in the data for age at onset of ossification (table H).

The failure of these studies to show socioeconomic effects on age at onset of ossification

may be due to the fact that they were not designed for this purpose or, perhaps, such effects

are slight. It has been suggested that socioeconomic status has more effect on the onset of

ossification in infancy and childhood than in

adolescence.1 51

The median ages at onset of ossification,

estimated from the national survey data for

youths, for the adductor sesarnoid in boys and

the flexor sesamoid in girls are not related consistently to family income. However, the onset

of ossification of the flexor sesamoid in boys is

markedly delayed in the lowest family income

group. In generzd, these findings are in agreement with earlier reports that the onset of ossification is rather insensitive to environmental

effects, but it is not completely insensitive. This

is clear from the rather large differences between

corresponding ages for Negroes in the United

States and Africa.80 ~81

Epiphyseal fusion. –There are no previous

studies of the influence of socioeconomic factors on age at epiphyseal fusion, however, it can

be concluded from the data of Low et aL39 that

such differences are probably small. Reported

data concerning the age at which growth in

stature ceases are not helpful because elongation

of the trunk continues after the cessation of

elongation in the Iimbs.1 59 Furthermore, serial

data from individuals studied until at least age

25 years are not available for low socioeconomic

groups. Such data are necessary, however, to

determine when growth in stature has ceased in

an individual.160

The national survey data show the absence

of a close interrelationship between

socioeconomic status judged by broad groupings

of either family income or parental education

and various aspects of skeletal maturation (mean

skeletal age, bone-specific skeletal ages and their

ranges, onset of ossification, and epiphyseal

fusion). It is important, however, to stress that

these findings relate to only a limited range of

socioeconomic status; real effects may be present at lower levels than those studied. If such

effects were present, they might reflect the

influence of differences in illness experience and

diet. The literature concerning these factors will

be reviewed briefly.

Illness

Onset of ossification.-The influence of illness

on age at onset of ossification in children has

40
been reviewed recently.2 There have not been

corresponding reports for youths, perhaps because so few centers begin to ossify between 12

and 17 years in the areas of the skeleton that are

usually radiographed for skeletal age assessments. The evidence indicates that the usual illnesses of childhood have little or no effect, but

when effects occur they may differ among

bones. There is little doubt that very severe illnesses retard the onset of ossification in children, but all the previous reports for children

have come from either the Brush Foundation

Study or the Fels Research Institute. These

reports relate to “normal” volunteers in whom

severe illnesses were uncommon. Additionally,

the timing of radiographic examinations was

scheduled according to chronological age; it was

not planned to maximize the possibility of

demonstrating the effects of illnesses. In a schedule designed for this purpose, examinations

would be made before, during, and after each

illness.

It has been claimed that unusual orders of

onset of ossification are due to illnesses near the

time of ossification of particular centers; as a

res u 1t ossification of these centers is deIayed.1O)18 $6z ~6A The report of Garn and Rohmarm161 f or children, and that of Hansman and

Maresh66 for children and youths do not support this view. If illnesses had such an effect,

they would be associated with increases in the

ranges of bone-specific skeletal ages within radiographs. This subject has not been studied adequately; reports based on very few individuals

have led to conflicting conclusions,l A8,] 6z,]63

In a large-scale study, it has been shown that the

median order of onset of ossification in the

hand-wrist is the same in Guatemala boys as in

boys in southwestern Ohio and that the variability of sequence was similar in both groups,

although illnesses were much more common in

the Guatemalans.164

Skeletal maturation. –In youths, skeletal

maturation is retarded by severe illnesses but it

accelerates during the catchup growth that may

follow the illness. 16s The nature of the illness

may be important. Bashe and Ratnerl 66,167

assessed 1,054 hand-wrist radiographs of children and youths hospitalized because of tuberculosis. About half of these patients were Negro

and all were of low socioeconomic status, despite which many were skeletally advanced. In

these patients there was no apparent relationship

between skeletal maturity level, or the ranges of

bone-specific skeletal ages within individuals,

and either the severity or the duration of the

disease.

Epiphyseal fusion. –Reports are not available

concerning the influence of generalized illnesses

on age at epiphyseal fusion.

Diet

There is no doubt that undernutrition retards the onset of ossification and skeletal maturation and, presumably, it retards epiphysea.1

fusion. Many studies are difficult to interpret

because of confounding variables and the lack of

reliable information concerning specific dietary

factors. Commonly of course, undernutrition is

associated with a high incidence of disease, poor

housing, and racial differences.

Onset of ossification. –There is convincing

evidence that malnutrition retards the onset of

ossification, but during adolescence these effects

tend to be smalll G1 or absent.168 Dreizen et

al.,16 9 using serial radiographs, studied the

onset of ossification in 541 undernourished

white urban children and youths in AIabama.

There was a marked delay that tended to be

greater in girls than in boys (table P).

In generaI, in the data of Dreizen et al,l 69

the standard deviation Ievels for ages at onset of

ossification in the late ossifying bones (adductor

and flexor sesarnoids) were higher than those for

bones that ossify during childhood. This is in

contrast to the claim of Frisancho et all51

Skeleta[ maturation. –Undernutrition retards

skeIetaI maturation and dietary supplementation

accelerates it in youths.lAs~lA6SlGG>170-17G

These effects are less marked in girls than in

boys.15 5 Skeletal maturation is slow also in

youths with inflammatory bowel disease;1 76

Table P. Retardation (years) in age of onset of ossification of

hand-wrist centers in malnourished white youths (data of

Dreizen et al.. 1958)169

Hand-wrist bones I BOYS I Girls

Adductor sesamoid .............................................

I

-0.1

I

-0.7

Flexor sesamoid .................................................. -0.7 –1.7

41
this may be a result of the associated malnutrition.

Few have studied the effects of specific nutrients, but an increased rate of maturation in

skeletally retarded youths occurs after the miIk

intake is increased.1 71 J177 Mack and Urbachl72 showed that restriction of calories, in

association with a protein intake at the recommended level, resulted in retardation of skeletal

maturation. Others consider that the level of

protein intake may be a more important factor

than the level of caloric intakes g Both workers

may be reporting correctly; the difference between the reports could reflect differences

between the groups studied in their deficiencies

of specific nutrients or groups of nutrients; the

bulk of the evidence shows that skeletal maturatio n is retarded in undernourished youths

whether the main lack is in calories or proteins.151j173~178

Malnutrition apparently has a differential

retarding effect across bones. Dreizen et al. I r g

reported that the carpals and the bones of the

fifth finger were more retarded than other

hand-wrist bones in undernourished Alabama

children and youths of British ancestry. An

attempt was not made, however, to estabIish

whether there were corresponding real differences in bone-specific skeletal ages in well-nourished children within the same population

group. It is well to be cautious when assessing

their conclusions. The differences reported by

Dreizen et all79 could reflect variations between these workers and Greulich and Pyle in

the ways in which bone-specific skeletal ages

were assessed.

Mass6 and Hunt81 have claimed that skeletal

retardation due to malnutrition is less marked in

the carpa.ls than in the short bones of the handwrist. Whichever of these conflicting views is

correct, acceptance of Todd’s attitudels that

one should use the most advanced centers as a

guide to actuaI maturity would lead to the employment of the centers that are least sensitive

to environmental influences. This would be inappropriate in many circumstances.

In general, overnutrition has effects in experimental animals that are the opposite to the

effects of undernutrition.18 O~1s I The changes

in overfed animals resemble those in overweight

or obese youths,ls z‘1 g 1 although a significant

association between overnutrition and accelerated skeletal maturation was not found by

Hortling et alls 3 except in obese adolescents

who were also short.

Within age groups, the level of skeletal

maturity is correlated positively with weight and

subcutaneous fat thickness,ls Y1s G>1g z but this

relationship is not close. The acceleration of

skeletal maturation is more marked in those who

have been obese for a long timel g0 or in whom

lean body mass is increased.193 It has been

reported that the effect of ovemutrition on the

rate of skeletaI maturation is equal in both

sex e S;l 9 * others consider the effect more

marked in girls than boys.1 90 Furthermore, it

has been claimed that the acceleration of skeletal maturation in obese youths is more marked

in the Iate than in the early ossifying carpals.1 g 1

Probably, however, this reflects only the greater

variabilityy of the ages at onset of ossification in

the carpals that are Iate to ossify.

Epiphyseal fusion. –Data from malnourished

children and youths who received a milk supplement have been reported by Spies et all Tq With

supplementation, skeletal maturation was accelerated in the children, but in the youths there

was no reduction in the delay of epiphyseal

fusion.14 5 It has been claimed that malnutrition

delays epiphyseal fusion to similar extents in

each sex and in each bone. 14s It is difficult to

determine the accuracy of this claim because

satisfactory reference data for the sequence of

epiphyseal fusion and the distribution of ages at

epiphyseal fusion have not been available.

SUMMARY

In this report, data for the skeletal maturity

of the right hand-wrist in noninstitutiona.lized

youths age 12-17 years are analyzed and described in respect to race, geographic region, size

and type of community, family income, and

parental education. The original data were

obtained from radiographs taken during the

Health Examination Survey of 1966-1970. For

this survey, a representative sample of 7,514

youths was chosen from the entire U.S. population within the age range 12-17 years. Examinations were made of 90 percent (6,768) of the

youths who had been chosen.

42
The radiographs were assessed, bone by

bone, by specially trained medical students who

dld not know either the age or the sex of any

youth whose radiograph was assessed. This

removed several sources of bias. The assessments

were all made against male standards, thus providing a unique opportunity to establish the true

extent of the sex-associated differences in rates

of skeletal maturation. Later, the ages assigned

to the girls were adjusted to female equivalent

values, using a set of sex-associated differences

in skeletal maturity reported by Pyle et zd.g In

this summary, reference will be made not only

to the data from the present survey but also to

the data from the corresponding survey of children 6-11 years.z33

Negro boys tend to be more mature skeletally than white boys at 6-9, 11, and 13 years,

but not at other ages within the range 6-17

years. Negro girls, however, are more mature

skeletally than white girls at all ages except 8,

16, and 17 years. It must be stressed that the

differences between the means are small, which

is in agreement with several earlier reports. The

mean skeletal ages for both white and Negro

boys are markedly less than the mean chronological ages at 9-12 years, showing, as reported

earlier, that the Greulich-Pyle Atlas standards

during this age range are set much too high for

the total U.S. population. There is a similar pattern in the girls, but the differences between the

mean skeletal and mean chronological ages are

smaller. While the levels of skeletal maturity for

whites in the United States are close to those

reported for northern European children, levels

of skeletal maturity for Negroes in the United

States are substantially accelerated compared

with groups of Negroes in Africa and Jamaica.

In the girls, whether white or Negro, the

skeletal ages (female equivalent values) are markedly retarded (less than chronological age) after

15 years. Almost certainly, this is due to the use

of inappropriate sex differences to transform to

female equivalent values the skeletal ages obtained against the male standards. A survey of

earlier literature had led to the expectation that

almost all hand-wrist bones would be adult in a

typical girl at 17.5 years; actually, only 22 percent of the girls age 17.0-17.9 years had all their

hand-wrist bones mature. Even if the maximum

value of the male set of standards were assigned

to each excluded girl, this would have influenced

only slightly the mean skeletal ages (female

equivalent values) for the girls. The large retardation of female equivalent values at older ages is,

almost certainly, due largely to the inaccuracy

of the sex-associated differences used to obtain

the female equivalent values.

There is no evidence that the bones of U.S.

children and youths are now maturing more

rapidly than in recent decades. There is evidence

that any such changes have been absent or slight

in white U.S. children of middle socioeconomic

status; conclusions for the total population

await the analysis of data from repeated national

surveys.

Mean skeletal ages tend to be more advanced

in Negro boys than in white boys at most ages

up to 10 years but not, in general, later. The

mean skeletal ages tend to be more advanced in

Negro than in white girls at all ages except 8, 16,

and 17 years. The mean hand-wrist skeletal ages

are more variable in boys than in girls,but there

are no consistent differences in variability

between white and Negro youths. There are statistically significant differences in bone-specific

skeletal ages between white and Negro groups of

boys when each bone is considered separately,

but there is a general tendency for each bone to

be more mature in white than Negro boys from

12 to 17 years. The slight tendencies noted are

in the reverse direction to those reported earlier

from the national survey of children. Similarly,

the white-Negro differences in both the mean

ranges of bone-specific skeletal ages within single

hand-wrists and in the variability of these ranges

are too small to be statistically significant. In the

girls, there is an opposite tendency that is not

significant for the majority of the individual

bones to be more mature in Negro than in white

girls from 7 to 17 years.

The white-Negro differences in both the

mean ranges of bone-specific skeletal ages within

single hand-wrists and in the variability of these

ranges are too small to be statistically significant. Also, there are no consistent white-Negro

differences in the ages at onset of ossification of

the adductor and flexor sesamoids.

Epiphyseal fusion, judged from the median

ages, occurs in the same sequence in both white

and Negro youths. Fusion occurs significantly

earlier in white than in Negro youths of both

43
sexes in metacarpal I, proximal phalanges I-V,

and middle phalanges II-V. Among girls there are

also significant racial differences in the opposite

direction for the ulna; metacarpal II-V; and distal phalanges I, II, and IV.

After adjusting for effects associated with

chronological age and racial distribution, U.S.

children age 6-11 years in the Northeast and

Midwest Regions tend to be somewhat advanced

skeletally, although much of the observed difference could have been due to chance.3 Among

youths in the United States age 12-17 years, the

differences in skeletal maturity between regions

are small also. Youths in the South tend to be

more advanced and those in the Midwest less

advanced than youths in the other two regions.

There are inconsistencies between variations

by geographic region in mean skeletal ages and

those in age at onset of ossification. In part, this

may reflect the few hand-wrist bones in which

ossification had not occurred by age 12 years. If

there are real regional differences in the United

States, it is probable that they occur only among

much smaller regions than those analyzed. When

each region is considered as a whole, there are

only minor differences among the four large

heterogeneous regions into which the United

States was divided for the purpose of this national survey.

The earlier literature indicates that socioeconomic factors exert a definite influence on the

rate of skeleta.1maturation, but these effects are

smalI unless extreme groups are compared. The

present national survey data are consistent with

these earlier findings.

Within both white and Negro groups of

youths, mean skeletal age is not related consistently to family income. Nevertheless, except at

the extremes of family income where the estimates are less reliable because of small sample

size, white boys tend to be more mature skeleta.lly than Negro boys and white girls less mature

in this respect than Negro girls within corresponding family income groups. In the national survey data, there is a similar pattern of

inconsistent differences associated with family

income for bone-specific skeletal ages, the range

of these ages within individual radiographs, and

onset of ossification. However, the data relating

to onset of ossification are somewhat more consistent, especially in girls, but the differences

between family income groups are small.

In the present report, numerous references

have been made to earlier studies of smaller and

less representative groups of youths in this country and abroad. These other studies have provided much important information, but the data

from the present national survey together with

those from the previous survey of youthsl $3

provide, for the first time, estimates that are

applicable to the total U.S. population in the age

range 6-17 years.

000

44
REFERENCES

1National Center for Health Statistics: Skeletal

maturity of youths 12-17 years, United States, by A. F.

Roche, J. Roberts, and P. V. V. Hamill. Vital and Health

Statistics. Series 11-No. 160. DHEW Pub. No. (HRA)

77-1642. Health Resources Administration. Washington.

U.S. Government Printing Office, Nov. 1976.

zNational Center for Health Statistics: Skeletal

maturity of children 6-11 years, United States, by A. F.

Roche, J. Roberts, and P. V. V. Hamill. Vital and Health

Statistics. Series 11-No. 140. DHEW Pub. No. (HRA)

75-1622. Health Resources Administration. Washington.

U.S. Government Printing Office, Nov. 1974.

‘National Center for Health Statistics: Skeletal

maturity of children 6-11 years: Racial, geographic area

and socioeconomic differentials, United States, by A. F.

Roche, J. Roberts, and P. V. V. Hamill. Vital and Health

Statistics. Series 1 l-No. 149. DHEW Pub. No. (HRA)

76-1631. Health Resources Administration. Washington.

U.S. Govwnment Printing Office, Oct. 1975.

4National Center for Health Statistics: Origin,

program and operation of the U.S. National Health

Survey. Vital and Health Statistics. PHS Pub. No.

1000-Series l-No 1. Public Health Service. Washington.

U.S. Government Printing Office, Aug. 1963.

5National Center for Health Statistics: Plan and

initial program of the Health Examination Survey. Vital

and Health Statistics. PHS Pub. No. 1000-Series l-No. 4.

Public Health Service. Washington. U.S. Government

Printing Office, July 1965.

6National Center for Health Statistics: Cycle I of the

Health Examination Survey, sample and response,

United States, 1960-62. Vital and Health Statistics. PHS

Pub. No 1000-Series 1l-No. 1. Public Health Service.

Washington. U.S. Government Printing Office, Apr.

1964.

7National Center for Health Statistics: Plan,

operation and response results of a program of children’s

examinations. Vital and Health Statistics. PHS Pub. No.

1000-Series 1-No. 5. Public Health Service. Washington.

U.S. Government Printing Office, Oct. 1967.

‘National Center for Health Statistics: Plan and

operation of a Health Examination Survey of U.S.

youths 12-17 years of age. Vital and Health Statistics.

PHS Pub. No. 1000-Series l-No. 8. Public Health

Service. Washington. U.S. Government Printing Office,

Sept. 1969.

‘Pyle, S. I., Waterhouse, A. M., and Greulich, W. W.:

A Radiographic Standard of Reference for the Growing

Hand and Wrist. Chicago. Year Book Medical Publishers

Inc., 1971.

10 Greulich, W. W., and Pyle, S. I.: Radiographic Atlas

of Skeletal Development of the Hand and Wn”st, 2d ed.

Stanford, Calif. Stanford University Press, 1959.

11 Roche, A. F.: Lateral comparisons of the skeletal

maturity of the human hand and wrist. Am. j.

Roentgenol. Radium Ther. Nucl. Med. 89:1272-1280,

1963.

12 Roche, A. F., Davila, G. H., Pastemack, B. A., and

Walton, M. J.: Some factors influencing the replicabiIity

of assessments of skeletal maturity (Greulich-Pyle). Am.

J. Roentgenol. Radium Ther. Nucl. Med. 109:299-306,

1970.

13National Center for Health Statistics: Body weight,

stature, and sitting height: white and Negro youths

12-17 years, United States, by P. V. V. HamiU, F. E.

Johnston, and S. Lemeshaw. Vital and Health Statistics.

Series 1l-No. 126. DHEW Pub. No. (HRA) 74-1608.

Health Resources Administration. Washington, U.S.

Government Printing Office, Aug. 1973.

14National Center for Health Statistics: Age at menarche, United States, by B. MacMahon. Vital and Health

Statistics. Series 11-No. 133. DHEW Pub. No. (HRA)

74-1615. Health Resources Administration. Washington.

U.S. Government Printing Office, Nov. 1973.

15 Simmons, K., and Greulich, W. W.: Menarcheal age

and the height, weight and skeletal age of girls age 7 to

17 years. J. Pediatr. 22:518-548, 1943.

16Flory, C. D.: Osseous development in the hand as an

index of skeletal development. So c. Res. Child Dev.

Monogr. 1, 1936. pp. 1-141.

17Simmons, K.: The Brush Foundation study of child

growth and development. II. Physical growth and

development. Sot. Res. Child Dev. Monogr., No. 37,

1944.

] 8Todd, T. W.: Atlas of Skeletal Maturation (Hand).

St. Louis. C. V. Mosby Co., 1937.

] ‘Johnston, F. E.: A Lon@udinal Study of Skeletal

Maturation and Its Relationship to Growth in

Philadelphia White Children; A Dissertation in

Anthropology. Unpublished doctoral dissertation,

University of Pennsylvania, 1962.

20 Krogman, W. M.: Growth of head, face, trunk, and

limbs in Philadelphia white and Negro children of

elementary and high school age. So c. Res. Child Dev.

Monogr., No. 136, 1970.

45
21 Fry, E. I.: Skeletal age by guess and by Tanner. II.

Large sample analysis. Am. J. Phys. Anthropol. 25:202,

1966. (Plus personal communication.)

22 Maresh, M. M.: Measurements from roentgenograms,

heart size, long bone length, bone, muscle and fat

widths, skeletal maturation, in R. W. McCammon, cd.,

Human Growth and Development. Springfield, Ill.

Charles C Thomas, 1970.

23Malina, R. M., and Johnston, F. E.: Significance of

age, sex, and maturity differences in upper arm

composition. Res. Q. Am. Assoc. Health Phys. Educ.

38:219-230, 1967.

24 Todd, T. W.: Differential skeletal nKdUHitiOII in

relation to sex, race variability and disease. Child Dev.

2:49-65, 1931.

25 U.S, Bureau of the census: statistical Abs@acts of

the United States, 1976, 97th ed. Washington. U.S.

Government Printing Office, 1976.

26Tanner, J. M., Whitehouse, R. M., and Healy, M. J.

R.: A New System for Estimating Skeletal Maturity

from the Hand and Wrirt, With Standards Den”ved from a

Study of 2,600 Healthy British Children. Parts I and II.

Paris. International Children’s Centre, 1962.

27 Tanner, J. M., Whitehouse, R. H., and Goldstein, H.:

A Revised System for Estimating Skeletal Maturity from

Hand and Wrist Radiographs, With Separate Standards

for Carpals and Other Bones (T. W. II System). Paris.

International Children’s Centre, 1972.

28~dersen, E.: skeletal maturation of Danish schooI

children in relation to height, sexual development, and

social conditions. Acts Paediatr. Stand. Suppl. 185,

1968.

29 Roche, A. F., Davila, G. H., and Eyman, S. L.: A

Comparison between Greulich-Pyle and Tarmer-Whitehouse assessments of skeletal maturity. Radiology

98:273-280, 1971.

30 Clark, B. : A comparison of two methods of

assessing skeletal maturity using hand-wrist radiographs.

NaO Zo. 4:11-18, 1974.

f 3 Roche, A. F.: A study of skeletal maturation in a

group of Melbourne children. Austr. Paediatr. J.

3:123-127, 1967.

32 Kopczy&ka, J.: Determination radiologique de la

maturation osseuse. Ann. Radiol. 7:308-314, 1964.

33Malina, R. M.: Patterns of development in skinfolds

of Negro and white Philadelphia children. Hum. Biol.

38:89-103, 1966.

34~~~a, R. M.: skeletal matuation rate ~ North

American Negro and white children. Nature 223:1075,

1969.

35Malina, R. M. Personal communication, 1972.

36 Malina, R. M., Holman, J. D., and Harper, A. B.:

Parent size and growth status of offspring. Sot. Biol.

17:120-123, 1970.

37Marshall, W. A., Ashcroft, M. T., and Bryan, G.:

Skeletal maturation of the hand and wrist in Jamaican

children. Hum. Biol. 42:419-435, 1970.

38Michaut-Barthod, E.: La maturation osseuse des

adolescents % Dakar, in Compte Rendu de la XIe

Reunion des Equipes Charg;es des Etudes sur la

Croiwance et le D.s%eloppement de l’Enfant Normal,

Londres, 1972, Paris. Centre International de L’Enfance,

1972. Pp. 75-76.

39Low, W. D., Chan, S. T., Chang, K. S. F., and Lee,

M. M. C.: Skeletal maturation of southern Chinese

chiklren. Child Dev. 35:1313-1336, 1964.

40 Greufich, W. W.: A comparison of the physical

growth and development of American-born and native

Japanese children. Am. J. Phys. Anthropol. 15:489-515,

1957.

41 Greulich, W. W., and Pyle, S. I.: Radiographic Atlas

of the Skeletal Development of the Hand and Wrikt.

Stanford, Calif. Stanford University Press, 1950.

42 Sutow, W. W.: Skeletal maturation in healthy Japanese children, 6 to 19 years of age; comparison with skeletal maturation in American children. Hiroshima ]. Med.

Sci. 2:181-191, 1953.

43 Sugiura, Y., and Nakazawa, O.: Bone Age: Roentgen Diagnosis of Skeletal Development. Tokyo. ClmgaiIgaku Co., 1968.

44 Sutow, W. W., and Ohwada, K.: Skeletal standards

of healthy Japanese children from age 6 to 19 years.

Clin. Pediatr, (Japan). 6:738-746, 1953.

45 Ashizawa, K.: Rapport preliminaire de la maturation osseuse des enfants Japonais par la m&ho~ de Tanner-whitehouse in Compte Rendu de la Xe Reunion des

Equipes Charg;es des Etudes sur la Croissance et la D[-

veloppement de l’Enfant Normal, Davos, Suisse, 1970.

Paris. Centre International de L’Enfance, 1970.

46 Kimura, K.: Skeletal maturation in Japanese as assessed by the Oxford and Tanner-Whitehouse methods.

Acts Anat. Nippon. 47:358-372, 1972.

47Tokai, T.: Somatic growth in Japan. XII International Congress of Pediatrics, Memoirs, Mexico, 1968.

1:44-52, 1968.

48 Kane, K., and Chung, C. S.: Do American born

Japanese children still grow faster than native Japanese?

Am. J. Phys. Anthropol. 43:187-194, 1975.

49 Gmenwald, p., Funakawa, H., Mitani, S., Nishimura,

T., and Takeuchi, S.: Influence of environmental factors

on foetal growth in man. Lancet i:1026-1028, 1967.

5OKimura, K.: Roentgenographic studies of the hand

and wrist bones in Japanese-American hybrids. Jap. Sot.

Ethn., 20th Session, 1965. pp. 188-190.

51Kimura, K.: On the skeletal maturation of the

Japanese-American hybrids. A preliminary report. J.

Anthropol. Sot. Nippon. 79:21-29, 1971.

52 Bayley, N.: The accurate prediction of growth and

adult height. Mod. Probl. Paediatr. 7:234-255, 1962.

53Malina, R. M.: Skeletal maturation studied longitudinally over one year in American whites and Negroes

six through thirteen years of age. Hum. Biol.

42:377-390,1970.

54 National Center for Health Statistics: Height and

weight of children: Socioeconomic status, United States,

by P. V. V. Hamill, F. E. Johnston, and S. Lemeshow.

Vital and Health Statistics. PHS Pub. No. 1000-Series

1l-No. 119. Public Health Service. Washington. U.S.

Government Printing Office, Oct. 1972.

55 Thompson, G. W., Popovich, F., and Luks, E.: Sex46
ual dimorphism in hand and wrist ossification. Growth

37:1-11, 1973.

56 Roche$ A. F., and Davila, G. H.: The reliability of

assessments of indhidual hand-wrist bones. Hum. Biol.

48:585-597.1976.

5 ‘Acheson, R. M.: The Oxford method of gyessing

skeletal maturity. CGin.Anthropol. 10:19-39, 1957.

58Mathiasen, M. S.: Determination of bone age and

recording of minor skeletal hand anomflles in normal

children. Dan. Afed. Bull. 20:83-85, 1973.

59Johnston, F. E., and Jahina, S. B.: Contribution of

carpal bones to assessment of skeletal age. Am. ]. Phys.

Anthropol. 23:349-354,1965.

60 Roche, A. F., Rohmann, C. G., French, N. Y., and

Davila, G, H.: Effect of training on replicability of assessments of skeletal maturity (Greulich-Pyle). Am. J.

Roentgtmol. Radium Ther. Nucl. Med. 108:511-515,

1970.

61 Roche, A. F., Wainer, H., and Thissen, D.: Skeletal

hlaturity, The Knee Joint as a Biological Indicator. New

York: Plenum Publishing Corporation, 1975.

62 Pryor, H, B., and Carter, H. D.: Phases of adolescent

development in girls. Calif and Western Med. 48:89-94,

1938.

63 Francis, C. C.: Factors influencing appearance of

centers of ossification during early childhood. Am. J.

.Dis. Child. 59:1006-1012, 1940.

64 Buehl, G. G., and Pyle, S. I.: The use of age at first

appearance of three ossi~lcation centers in determining

the skeletal status of children. j. Pediatr. 21:335-342,

1942.

b5 Sontaq, L. W., and Lipford, J.: The effect of illness L

and other factors on appearance pattern of skeletal epi-

‘h~$~~!~~~~~.?~?~~;;~;. M.: A longitudinal

study of skeletal maturation. Am. J. Dis. Child.

101:305-321, 1961.

67Todd, T. W.: Growth and development of the child:

Part II. Anatomy and Physiology, in White House Conference on Child Health and Protection, New York. Centur Co., 1932.

6] Francis, C. C.: Factors influencing appearance of

centers of ossification during early childhood. Am. J.

Dis. Child. 57:817-830, 1939.

69 Francis, C. C., and Werle, P. P.: The appearance of

centers of ossification from birth to 5 years. Am. J.

Phys. Anthropol. 24:273-299, 1939.

70 Grculich, W. W.: The relationship of skeletal status

to the physical growth and development of chddsen, in

E. J. Boell, cd., Dynamics of Growth Processes. Princeton, N. J, Princeton University Press, 1954, pp. 212-223.

7~Harding, V. S. V.: A method of evaluating osseous

development from birth to 14 years. Child Dev.

23:247-271,1952.

72Garn, S. M., Rohmann, C. G., and Silverman, F. N.:

Radiographic standards for postnatal ossification and

tooth calcification. Med. Radiogr. Photogr. 43:45-66,

1967,

73Pyle, S. I., Stuart, H. C., Comoni, J., and Reed, R.

B.: Onsets, completions, and spans of the osseous stage

of development in representative bone growth centers of

the extremities. Sot. Res. Child Dev. Monogr. 26, No. 1,

1961.

74 Hansman, C. F.: Appearance and fusion of ossification centers in the human skeleton. Am. J. Roentgenol.

Radium Ther. Nucl. Med. 88:476-482, 1962.

75Joseph, J.: The sesarnoid bones of the hand and the

time of fusion of epiphyses of the thumb. J. Ant.

85:230-241, 1951.

76 Semp<. M.: Ages d’apparition du pisiforme et des

sesamoids, in Co mpte Rendu de la Xe R&nion des

Equipes Charg!es des Etudes sur la Croissance et le D;-

veloppement de l’Enfant Normal, Davos, Suisse, 1970.

Paris. Centre International de L’Enfance, 1970. p. 95.

77 RudzinsKl, B. W.: Puberty and its indices in hand

and wrist radiograms in boys from Warsaw schools.

Pediatr. Pol. 45:1447-1461, 1970.

78Donnan, E.: The slave trade into South Carolina

before the Revolution. Amer. Hist. Rev. 33:816-817,

1928.

79Curtain, P.: The Atlantic Slave Trade. Madison. University of Wisconsin Press, 1969.

8OMichaut-Bmthod, E.: Determination de z= Jfatura.

tion Osseuse de 227 Adolescents Dakarois par la M$th -

ode de Tanner- Whitehouse-Healy et @ar 1‘A tlas de Greulich et Pyle. M. D. thesis, Universit~ de Paris, 1971. pp.

58+7.

81Mass<, G., and Hunt, E. E., Jr.: Skeletal maturation

of the hand and wrist in West African children. Hum.

Biol. 35:3-25, 1963.

82 Garn, S. M., Rohmann, C. G., and Apfelbaum, B.:

Complete epiphyseal union of the hand. Am. J. Phys.

Anthropol. 19:365, 1961.

83 R,us5e11, w. J., Keehn, R. J., Ihno, Y., Hattori, F.,

Kogure, T., and Imamura, K.: Bone maturation in children exposed to the A-bomb in utero. Pediatr. Radiol.

108:367-374, 1973.

84 Eto, S.: A consideration about the time of closure

of the centers of the hand. Nippon Jinrui Gakkai-Nippon

Minzoku Gakki Joint Meeting, 1966. pp.1-74.

85 Helm, S., Siersbaek-Nielsen, S., Skieller, V., and

Bj6rk, A.: Skeletal maturation of the hand in relation to

maximum puberal growth in body height. Tandlaegebladet 75:1223-1234, 1971.

86 Chan, S. T., Chang, K. S. F., and Hsu, F. K.:

Growth and skeletal maturation of Chinese children in

Hong Kong. Am. J. Phys. Anthropol. 19:289-300, 1961.

87 Chang, K. S. F., Lee, M. M. C., Low, W. D., and

Kwan, E.: Height and weight of Southern Chinese children. Am. J. Phys. Anthropol. 21:497-509, 1963.

88 Tanner, J. M.: Growth at Adolescence, 2d ed. Oxford. Blackwell Scientific Publications, 1962.

89 Malcolm, L. A.: Growth and development in New

Guinea-a study of the Bundi people of the Madang district. MonogT. Inst. Human Biol. Papua, New Guinea.

No. 1:1-105, 1970.

90 Nation~ Center for Health Statistics: Height and

weight of youths 12-17 years, United States, by P. V. V.

Hamill, F. E. Johnston, and S. Lemeshow. Vital and

Health Statistics. DHEW Pub. No. (HSM) 73-1606.

47
Series 1l-No. 124. Health Services and Mental Health

Administration. Washington. U.S. Government Printing

Office, Jan. 1973.

91 Eveleth, P. B., and Tanner, J. M.: Worldwide variation in human growth. New York. Cambridge University

Press, 1976. p. 498.

92 Pryor, J. W.: The hereditary nature of variation in

the ossification of bones. Anat. Rec. 1:84-88, 1907.

93 Pryor, J. W.: Normal variations in the ossification of

bones due to genetic factors. j. Hered. 30:158-165,

1933.

94 Hess, A. F., and Abrarnson, H.: Familial retardation

in ossification of the carpal centers. J. Pediatr. 3:158-

165, 1933.

95 Key. W. E.: Radiological studies of the skeletons of

twins, triplets and quadruplets. J. Hered. 27:86-88,

1936.

96Garn, S. M., and Rohmann, C. G.: Parent-child similarities in hand-wrist ossification. Am. J. Dis. Child.

103:603-607, 1962.

97Hertzog, K. P., Falkner, F., and Garn, S. M.: The

genetic determination of ossification sequence polymorphism. Am. j. Hzys. Anthropol. 30:141-143, 1969.

98Reynolds, E. L.: Degree of kinship and pattern of

ossification; a longitudinal x-ray study of the appearance

pattern of different kinship groups. Am. J. Phys.

Anthropol. 1:405-416, 1943.

99 Sontag, L. W., and Reynolds, E. L.: Ossification sequences in identical triplets. J. Hered. 35:57-64, 1944.

100 Pryor, J. W.: Time of ossification of the bones of

the hand of the male and female and union of epiphyses

with the diaphyses. Am. J. Phys. Anthropol. 8:401-410,

1925.

10 IPryor, J. W.: Ossification as additional evidence in

differentiating identical and fraternal in multiple

births. Am. ]. Anat. 59:409-423, 1936.

102 Buschke, F.: The radiological examination of the

skeletons of triplets.]. Hered. 26:391-410, 1935.

103 Garn, S. M., Rohmann, C. G., and Davis, A. A.:

Gene tics of hand-wrist ossification. Am. J. Phys.

Anthropol. 21:33-40, 1963.

104Garn, S. M.: Determinants of size and growth during

the first three years, in A. Merminod, cd., The Growth

of the Normal Child During the First Three Years of

Life, Modern Problems in Pediatrics, VOL 7. 13aseL S.

Karger, 1962.

105Lwd, S. E. T.: A psycho.biologicd study of a set of

identical girl triplets. Hum. Biol. 5:1-34, 1933.

106Parkin, J. M., Neligan, G. A., Dee, P. M., and Simpson, W.: The influence of genetic differences, nutrition

and sex on the radiological appearances of the lower

limb ossification centers in newborn twins. Hum. Biol.

41:1-12.1969.

107Hewitt, D.: Some familial correlations in height,

weight and skeletal maturity. Ann. Hum. Genet.

22:26-35, 1957.

108 Rigler, L. G.: Roentgen studies of twins and triplets.

Radiology 30:461-470, 1938.

109 Reynolds, E. L., and Schoen, G.: Growth patterns

of identical triplets from 8 through 18 years. Child Dev.

18:130-151,1947.

11‘Pyle, S. I., Reed, R. B., and Stuart, H. C.: Patterns

of skeletal development in the hand. Pediatrics

24:886-903, 1959.

111 Hess, A. F., and Weinstock, M.: A comparison of

the evolution of carpal centres in white and Negro newborn infants. Am. J. Dis. Child. 29:347-354, 1925,

112Christie, A. U., Dunham, E. C., Jenss, R. M., and

Dippel, A. L.: Development of the center for the cuboid

bone in newborn infants; a roentgenographic study. Am.

]. Dis. Child. 61:471-482,1941.

113 Kelly, H. J., and Reynolds, L.: Appearance and

growth of ossification centers and increases in the body

dimensions of white and Negro infants. Am. J, Roentgenol. Radium Ther. Nucl. Med. 57:477-516, 1947. 1

114Christie, A.: Prevalence and distribution of ossification centers in the newborn infant. Am. J. Dis. Child.

77:355-361, 1949.

115Tompkins, W. T., and Wiehl, D. G.: Epiphyseal

maturation in the newborn as related to maternal nutritional status. Am. J. Obstet. Gynecol. 68:1366-1377,

1954.

116Garn, S. M., Sandusky, S. T., Nagy, J. M., and

McCann, M. B.: Advanced skeletal development in lowincome Negro children. J. Pediatr. 80:965-969, 1972.

1170wen, G. M., Kram, K. M., Garry, P. J., Lowe, J. E.,

and Lubin, A. H.: A study of nutritional status of preschool children in the United States, 1968-70. Pediatrics

L

53 Supp. to No. 4, pt.II): 597-646, 1974.

11 Lee, M. M. C., Chu, P. C., and Chan, H. C.: Magnitude and pattern of compensatory growth in rats after

cold exposure. J. Embryol. Exp. Morphol. 21(3):407-

416, 1969.

11 ‘Dearborn, W. F., and Rothney, J. W. M.: Predicting

the Child’s Development. Cambridge, Mass. Sci-Art Publishers, 1941.

12°Dearborn, W. F., Rothney, J. W. M., and Shuttleworth, F. K.: Data on the growth of public school chil.

&en; from the materials of the Harvard Growth Study.

Sot. Res. Child Dev. Monogr. 3(l): 1-136, 1938.

121 Roche, A. F.: Unpublished data.

122Maresh, M. M.: A forty-five year investigation for

secular changes in physical maturation. Am. J. Phys.

Anthropol. 36:103-110,1972.

123 National Center for Health Statistics: Height and

weight of children, United States, by P. V. V. Hamill,

F. E. Johnston, and W. Grams. Vital and Health Statistics. Series 1l-No. 104. DHEW Pub. No. (HRA) 75-1093.

Health Resources Administration. Washington. U.S. Government Printing Office, Sept. 1970.

124National Center for Health Statistics: Preliminary

findings of the first health and nutrition examination

survey, United States, 1971-1972: anthropometric and

clinical findings, by S. Abraham, F. W. Lowenstein, and

D. E. O’Connell. DHEW Publication No. (HRA) 75-1229.

Health Resources Administration. Washington. U.S. Government Printing Office, Apr. 1975.

125 U.S. Department of Health, Education, and Welfare,

Health Services and Mental Health Administration. Center for Disease Control: Ten-State Nutrition Survey,

1968-1970. Atlanta, Ga. Center for Disease Control,

1972.

48
126Mills, C. A.: Geographic and time variations in body

growth and age at menarche, Hum. Biol. 9:43-56, 1937.

127Mills, C. A.: Temperature influence over human

th and development. Hum. Biol. 22:71-74, 1950.

“Roberts, D. F.: Race, genetics and growth. J.

Biosoc. Sci. Supp. 1,43-67, 1969.

129 Fabry, C.: La fixation de chaux par Ie phosphate

tricalcique en milieu aqueux. Biochem. Biophys. A eta

14:401-406, 1954.

1‘0 Brookes, M., and May, K. U.: The influence of temp erature on bone growth in the chick. J. Anat.

111:351-363,1972.

131 Bmett, S. A., and Colemm, E. M.: The effect of

low environmental temperature on the reproductive

cycle of female mice. J. Endocrinol. 19(3):232-240,

1959.

132 Barnett, S, A.: Genotype and environment in tail

len th in mice. Q. ]. Exp. Physiol. 50(4) :417-429, 1965.

13\Lee, M. M. CO,Chu, p. C., ~d Cha, H. C.: Effects

of cold on the skeletal growth of albino rats. Am. J.

Anat. 124(2):239-249, 1969.

134Jones, D. L,, and Hemphill, W.: Height, weight and

other physical characteristics of New South Wales children. Part II. Children under five years of age. Health

Commission of New South Wales. G79394-lG 5705,

1974.

135 Stettner, E.: &er die Beziehungen der Ossification

des Handskeletts zu Alter und Ltigenwachstum bei

gesunden und kranken Kindem von der Geburt bis zur

Pubertiit. Arch. Kinderheilk. 69:27-62,1921.

136Wola&ki, N., and Lasota, A.: Physical development

of countryside children and youth aged 2 to 20 years as

compared with the development of town youth of the

same age. Z. itforph. Anthropol. 54(3):272-292, 1964.

137Stettner, E.: her de Beziehungen der Ossification

des Handskeletts zu Alter und L5ngenwachsturn bei

gesunden und kranken Kindem von der Geburt bis zur

Pubertiit, Arch, Kinderheilk, 68:342-368, 1920.

1~8Stettner, E.: Uber die Beziehungen der Ussifikation

des Handskcletts zu Alter und IXngenwachstum bei

gesunden und kranken Kindem von der Geburt bis zur

Puberdit. Arch. Kinderheilk. 68:439-466, 1920.

139Maleki, M.: Food consumption and nutritional

status of 13 year old village and city schoolboys in Faes

Province, Iran, EcoC. Food Nubr. 2:39-42, 1973.

140 Backstrtimjarvinen, L.: Heights and weights of Finnish children and young adults. Ann. Paediatr. Supp. 23,

116 pp., 1964.

141 v~aoras, V., ~lld Lmos, K.: Biome&ic chMacteri~-

tics of Greek pupils in elementary schools. Iatriki.

15:266-276,1969.

142 Cristesgu, M.: Aspecte aIe cresterii si dezvoharii

adolescentilor din Republics Socialist Romania. Editum, Academiei Republicii Socialist Romania, Bucharest, 1969.

143 Greulich, W. W.: The growth and developmental

status of Guamanian school children in 1947. Am. J.

Phys. Anthropol. 9:55-70,1951.

144 Greulich, W, Wo, Crismon, C. S., ~d Tm.ner, M. L.:

The physical growth and development of children who

survived the atomic bombing of Hiroshima or Nagasaki.

j. Pediatr. 43:121-145,1953.

145 Dreizen, S., Snodgrasse, R. M., Webb-Peploe, H.,

and Spies, T. D.: The effect of prolonged nutritive failure on epiphyseal fusion in the human hand skeleton.

Am. J. Roentgenol. Radium Ther. Nucl. Med.

78:416-470,1957.

~46 Grande co~fi, F., ~d R. f Caballo) J.: Alimentacitfn y desarrollo infantil; estudio radiografico comparative del desarrollo escuel&ico de dos grupos de nifios en

edad escolar y distinto nivel econ6mico. Rev. Glin.

Espa+Z 14:13-16, 1944.

147 Neyzi, O., Yalcjnda& A., and Alp, H.: Socioeconomic level and physiological maturation in the Turkish

child. Pro c. XIII Internat. Congr. Peal., Vienna.

15:55-60, 1971.

148 Acheson, R. M.: Maturation of the skeleton, in F.

Falkner, cd., Human Development. Philadelphia. W. B.

Saunders Co., 1966.

149 Kopczy&ka, J,: Further studies on the skeletal age

evaluated according to examination of bones of the hand

and wrist in children in Warsaw. Pediatr. Pol. 36:845-

853, 1961.

150Deschamps, J.-P., and Benchemsi, N.: Maturation

o>seuse et conditions socio-$conomiques et culturelles

(Etude transversal sur 4526 enfants et adolescents).

Rev. Pediatrie 10:143-151, 1974.

151 Frisancho, A. R., Garn, S. M., and Ascoli, W.: Childhood retardation resulting in reduction of adult body

size due to lesser adolescent skeletal delay. Am. ]. Phys.

Anthropol. 33:325-336,1970.

152Gmf f=, M.: L’influence des facteurs sociaux sur la

croissance et le d&eloppement de l’enfant. Les Carnets

de l’Enfatzce 15:23-31, 1971.

153 Graffar, M., and Corbier, J.: Influence facteurs

socio-gconomiques, in La Croissance Normale. XXeCongr& de l’Association des P&liatres de Langue Fran@se,

Nancy. Paris. L’Expansion Ed., 1965.

154 Semp<, M.: De quelques facteurs extrins%ques agissant sur la croissance. Rev. Hyg. Med. Sot. 16:219-262,

1968.

155Abbott, O. D., Townsend, R. O., French, R. B., and

Ahmann, C. F.: Carpal and epiphyseal development:

Another index of nutritional status of rural school children. Am. J. Dis. Child. 79:69-81, 1950.

156Buzina, R.: Personal communication, 1973.

157Baldwin, T. T., Busby, L. M., and Garside, H. V.:

Anatomic growth of children; a study of some bones of

the hand, wrist, and lower forearm by means of roentgenograms. Univ. Iowa Stud. Child Welfare 4 (1):

1-85, 1930.

158McCammon, R. W.: Human Growth and Development. Springfield, Ill. Charles C Thomas, 1970.

159 Anderson, M., Green, W. T., Messner, M. B.: Growth

and predictions of growth in the lower extremities. J.

Bone Joint Surg. 45A: 1-14, 1963.

160 Roche, A. F., and Davila, G. H.: Late adolescent

growth in stature. Ped&ztrics 50:874-880, 1972.

161 Gmn, S. M., ~d Rohm~, c. G.: Variability in the

order of ossification of the bony centers of the hand and

wrist. Am. J. Phys. Anthropol. 18:219-230, 1960.

49
162pyle, so I., M~n, A. W., Dreizen, S., Kelly, H. J.,

Macy, I. G., and Spies, T. D.: A substitute for skeletal

age (Todd) for clinical use: the red graph method. ].

Pediatr. 32:125-136, 1948.

163Hoerr, N. L., Pyle, S. I., and Francis, C. C.: Radiographic Atlas of Skeletal Development of the Foot and

Ankle. A Standard of Reference. Springfield, Ill. Charles

C Thomas, 1962. p. 163.

164Yarbrough, C., Habicht, J.-P., Klein, R. E., and

Roche, A. F.: Determining the biological age of the preschool child from a hand-wrist radiograph. Invest.

Radiol. 8:233-243, 1973.

165Prader, A., Tanner, J. M., and von Hamack, G. A.:

Catch-up growth following illness or starvation; an

example of developmental canalization in man. ].

Pediatr. 62:646-659, 1963.

166Bashe, W. J., Jr., and Ratner, B.: Bone development

in children with tuberculosis. I. Maturation determined

by the Todd Method. Quart. Bull. Sea View Hosp.

15:49-61, 1954.

167Bashe, W. J., Jr., and Ratner, B.: Bone development

in children with tuberculosis. III. Studies with the Red

Gra h. Quart. Bull. Sea View Hosp. 15:71-82, 1954a.

16~B6har, M., Rohmann, C., Wilson, D., Viteri, F., and

“Garn, S. M.: Osseous development in children with

kwashiorkor. Fed. Proc. 23:338, 1964 (abstract).

169Dreizen, S., Snodgrasse, R. M., Webb-Peploe, H.,

and Spies, T. D.: The retarding effect of protracted

undernutrition on the appearance of the postnatal ossification centers in the hand and wrist. Hum. Ba’ol.

30:253-264, 1958.

170MacNair, V.: Effect of a dietary supplement on ossification of the bones of the wrist in institutional children. II. Effect of cod liver oil supplement. Amer. j. Dis.

Child. 58:295-319, 1939.

17 lMacNair, V. and Roberts, L. J.: Effect of a milk

supplement on the physical status of institutional children. II. Ossification of the bones of the wrist. Am. J.

Dis. Child. 56:494-509, 1938.

172Mack, P. B., and Urbach, C.: Study of institutional

children with particukr reference to the caloric value as

well as other factors of the dietary. Sot. Res. Child Dev.

Monogr. 13(1):1-93, 1948.

173Berridge, F. R., and Prior, K. M.: The skeletal development of the children at the beginning and end of the

period of experimental feeding. Med. Res. Council

287:119-130, 1954.

174Spies, T. D., Dreizen, S., Snodgrasse, R. M., Arnett,

C. M., and Webb-Peploe, H.: Effect of dietary supplement of nonfat milk on human growth failure; comparative response in undernourished children and in undernourished adolescents. Am. J. Dis. Child. 98:187-197,

1959.

175Acheson, R. M., Fowler, G. B., and Janes, M. D.:

Effect of improved care on the predicted adult height of

undernourished children. Nature 194:735-736, 1962.

176McCaffery, T. D., Nasr, K., Lawrence, A. M., and

Kirsner, J. B.: Severe growth retardation in children with

inflammatory bowel disease. Pediatrics 45:386-393,

1970.

177Dreizen, S., Snodgrasse, R. M., Parker, G. S., Curric,

C., and Spies, T. D.: Maturation of bone centers in hand

and wrist of children with chronic nutritive failure;

effect of dietary supplements of reconstituted milk

solids. Am. J. Dis. Child. 87:429-439, 1954.

178Chav4z, A., Hidalgo, C. P., and Pitol, A.: Maduracion

osea en dos grupos de nifios con diferente estado du

nutrici~n. Salud P~bl. M&Y. 6:705-717, 1964.

179Dreizen, S., Snodgrasse, R. M., Webb-Peploe, H.,

Dreizen, J. G., and Spies, T. D.: The sites of maturational strength and weakness in the developing hand

skeleton. Am. J. Roentgenol. Radium Ther. Nucl. Med.

82:490-500, 1959.

18 ‘Hammond, J.: Progress in the Physiology of Farm

Animals. Butterworth Scientific Publications. London.

Butterworth & Co., Ltd., 1954.

181 Dickerson, J. W. T., and Widdowson, E. M.: Chemical changes in skeletal muscle during development.

Biochem. J. 74:247, 1960.

182 Bruch, H.: Obesity in childhood: Physical growth

and development of obese children. Am. J. Dis. Child.

58:457-484, 1939.

183Hortling, H., de la Chapelle, A., Frisk, M., and

Widholm, O.: The syndromes of obesity and of delayed

growth in adolescence. Acts Med. Stand. (Suppl.) 412:

109-122, 1964.

184Mossberg, H.-O.: The X-ray appearance of the knee

joint in obese overgrown children. A eta Paediat. Stand.

38:509-516, 1949.

185 Garn, S. M., and Haskell, J. A.: Fat and growth

during childhood. Science 130:1711, 1959.

186Garn, S. M., and Haskell, J. A.: Fat thickness and

developmental status in childhood and adolescence. Am.

J. Dis. Child. 99:746-751,1960.

187 Fry, P. C.: A comparative study of “obese” children

selected’ on the basis of fat pads. J. Clin. Nutr.

1:453-467, 1953.

188 Peckos, P. S.: Caloric intake in relation to physique

in children. Science 117:631, 1953.

189Melhnau, W. J., Bongiovanni, A. M., and Hope, J.

W.: The diagnostic usefulness of skeletal maturation in

an endocrine clinic. Pediatrics 23:530-544, 1959.

190 Frisk, M., Widholm, O., Tenhunen, T., and Hortling,

H.: Overweight in adolescents–a complex problem. Ann.

Paediatr. Fenn. “12:234-245, 1966.

191Markuske, H.: Rontgenologische Untersuchungen

der Handwnrzelknocken adipbser Kinder. Z. Kinderheilk. 106:225-234, 1969.

192Maresh, M. M.: Changes in tissue widths during

growth, Roentgenographic measurements of bone, muscle, and fat widths from infancy through adolescence.

Am. J. Dis Child. 3:142-155, 1966.

193 Forbes, G. B.: Growth of the lean body mass during

childhood and adolescence. J. Pediatr. 64:822-827,

1964.

194National Center for Health Statistics: Quality control in a National Health Survey, by W. L. Schaibee.

Vital and Health Statistics. Series 2-No. 44. DHEW Pub.

No. (HRA) 74-1023. Health Resources Administration.

Washington. U.S. Government Printing Office, Feb.

1972.

50
195Nation~ Center for Health Statistics: Sample design

and estimation procedures for a national Health Examination Survey of children, by E. E. Bryant, J. T. Baird,

and H, W. Miller. Vital and Health StatzWcs. Series 2-No.

43. DHEW Pub. No. (HSM) 72-1005. Health Services

and Mental Health Administration. Washington. U.S.

Government Printing Office, Aug. 1971.

196Moore, W. M,: Compwability in skeletal maturation

research. Am. ]. l%ys. Anthropol. 35:411-415, 1971.

197Anderson, M., Hwang, S.-C., and Green, W. T.:

Growth of the normal trunk in boys and girls during the

second decade of life, related to age, matmity, and ossification of the iliac epiphyses. J. Bone Joint Surg.

47A:1554-1564, 1965.

~98Gray, S. W., and Lamons, F. P.: Skeletal development and tooth eruption in Atlanta children. Am. J.

Orthod. 45:272-277,1959.

lg9Acheson, R, M.. Fowler, G., Fry, E. I., Janes, M.,

Koski, K., Urbane, P., and van der Werff ten Bosch, J.

J,: Studies in the reliability of assessing skeletal maturity

from x-rays. Part 1. Greulich-Pyle Atlas. Hum. Biol.

35:317-349, 1963.

200 Roche, A. F. g Associations between the rates of

maturation of the bones of the hand-wrist. Am. J. Phys.

Anthropol. 33:341-348,1970.

2°1 Mazess, R. B., and Cameron, J. R.: Skeletal growth

in school children: maturation and bone mass. Am. J.

Phys. Anthropol. 35:399407, 1971.

202Ma~~d, D.: Etiution of the skeletal age method

of estimating children’s development: II. Variable errors

in the assessment of roentgenograms. Pediatrics

13:165-173, 1954.

2°3Anderson, M.: Growth, overgrowth, and matuxity:

observations based upon examination of serial roentgenograms of children with hemihypertrophy. Am. J. Phys.

Anthropol. 27:246, 1967.

2°4Moed, G., Wight, B. W., and Vandegrift, H. N.:

Studies of physical disability: reliability of measurement

of skeletal age from hand films. Child Dev. 33:37-41,

1962.

2°5Johnston, F. E.: Skeletal age and its prediction in

Philadelphia childxen. Hum. Biol. 35:192-201, 1963.

206 Demischj A., and Wartmann, P.: Calcification of

mandibular third molar and its relation to skeletal and

chronological age in children. Child Dev. 27:459473,

1956.

207 Koski, K., Haataja, J.,and Lappakiinen, M.: Skeletal

development of hand and wrist in Finnish children. Am.

J. Phys. Anthropol. 19:379-382,1961.

51
LIST OF DETAILED TABLES

1. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by race, chronological age at last

birthday, and sex: United States, 1966-1970 ...........................................................................................................................4....

2. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by geographic region, chronological age at last birthday, and sex: United States, 1966.1970 ................................................................................................c.c..c...

3. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by geographic region, chronological

age at last birthday, and sex: United States, 1966-1970 ...............................................................................................................

4. Mean skeletal age (hand-wrist) of youths by population size in urban areas and land use in rural areas of residence, chronological age at last birthday, and sex, with selected standard errors: Unitad States, 1966-1 970 ..........................................................

6. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by annual family income, chronological age at last birthday, and sex: United States,1966-1 970 ...................................................................................................

6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chronological age at last birthday, and sex: United States, 1966.1970 ......... .........................................................................................

7. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by education of first parent, chronological age of youth at last birthday, and sex: United States, 1966.1970 ....................................................................................

8. Selected percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family income, chronological age at last birthday, and sex: United States, 1966-1970 ...............................................................................

9, Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of white and Negro youths by chronological age in

years at last birthday and sex, with selected standard errors: IJnited States, 1966.1970 .......... ... ..................................................

10. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological age in

years at last birthday, and sex, with selected standard errors: United States, 1966-1 97 O..............................................................

11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last

birthday, and sex, with selected standard errors: United States, 1966-1970 .................................. ..............................................

12. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radio-opaque (not

adult) bones in the hand-wrist for white and Negro youths by chronological age in years at last birthday and sex: United

States, 1966-1970 ................................................................................................................................ ................................ .........

13. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radioopaque (not

adult) bones in the hand-wrist for youths by geographic region, chronological age in years at last birthday, and sex: United

States, 1966-1970 ................................................................................................................................ ................................ .........

14. Selected percentiles in the distribution of the individual youth’s range in bone-specific skeletal ages for the radio-opaque (not

adult) bones in the hand-wrist for youths by annual family income, chronological age in years at last birthday, and sex: United

States, 1966-1970 .................................................................. .............................................................. ................................ .........

15. Median (chronological) age of onset of ossification in selected hand-wrist bones for youths 12-17 years by race, region, annual

family income, and sex: IJnited States, 1966.lg71) .......................................................................................................................

16. Median age in months at epiphyseal fusion for selected hand-wrist bones of white and Negro boys and girls 12-17 years of

chronological age at last birthday: United States, 1966.1970 .......................................................................................................

53

54

55

66

57

58

60

61

64

70

78

86

86

87

87

88

52
Table 1. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by race, chronological age at last

birthdav, and sex: United States, 1966-1970

Standard of reference, sex, and chronological

age at last birthday

Male standard

Boys:

12 years ..................................................................................

13 years ................. .................................................................

14 years ..................................................................................

15 years ..................................................................................

16 years ..................................................................................

17 years ..o...............................................................................

Girls:

12 years ..................................................................................

13 years ..................................................................................

14 years ....b.............................................................................

15 years .................................................. ................................

16 years ..................................................................................

17 years ..................................................................................

Actual Values:

BOYS 12-17 years ....................................................................

Girls 12-17 years ....................................................................

Expected values:

Boys 12-17 years ... ...................................... ...........................

Girls 12-17 years.....................................................................

Female equivalent

Girls:

12 years ..................................................................................

13 years ..m.......... .....................................................................

14 years ..................................................................................

15 years ..................................................................................

16 years ..................................................................................

17 years ..................................................................................

White

I-h&

140.4

156.8

173.7

187.1

197.0

205.8

174.3

186.5

197.9

205.3

211.5

211.7

175.2

196.5

175.0

196.7

142.3

154.8

167.9

177.3

185.8

186.0

17.17

17.77

14.84

13.91

13.12

10.97

14.36

13.12

10.46

9.28

10.00

9.82

---

.-.

-..

. . .

11.72

10.89

8.87

8.01

8.78

8.63

Negro I Other races

I

Skeletal age in months

0.62

0.93

0.74

0.73

0.78

0.52

0.71

0.72

0.63

0.57

0.52

0.64

0.40

0.38

0.40

0.38

0.58

0.60

0.53

0.49

0.46

0.56

138.7

160.6

172.7

181.7

192.7

202.4

178.4

187.5

198.7

207.6

210.2

210.5

172.6

197.1

174.2

196.1

146.4

156.5

169.1

179.9

184.2

184.5

16.04

19.69

17.04

15.91

16.93

11.37

16.72

12.10

12.82

8.35

9.36

10.34

---

-..

-..

-..

13.72

10.10

10.91

7.24

8.20

9.06

2.84

3.10

2.03

1.09

2.93

1.65

2.40

1.09

1.70

0.81

0.96

2.14

1.17

0.85

1.18

0.84

1.97

0.91

1.45

0.70

0.84

1.88

149.3

164.5

170.7

197.3

188.9

209.1

184.5

187.2

198.8

204.6

206.6

220.0

182.7

198.4

179.2

196.0

152.5

156.2

168.3

175.9

178.6

197.0

105.58

52.37

54.06

5.02

74.35

1.05

9.43

132.41

140.57

64.71

146.06

155.56

6.32

3.80

6.29

3.78

7.79

110.50

119.00

55.63

126.26

139.30

NOTE: R = mean skeletal age (hand-wrist); SX = standard deviation of skeletal age; and s= = standard error of mean. Expected

values remove the effect of differences in the chronological age dktribution with respect to skeletal age over the 12-17-year age span by

indirect adjustment.

53
Table 2. Mean, standard deviation, and standard error of the mean skeletal age (hand-wrist) of youths by geographic region,

chronological age at last birthdav, and sex: United States. 1966-1970

Standard of reference, sex,

and chronological age

at last birthday

Male standard

Boys:

12 years ........... ....................

13 years ........... ....................

14 years ...............................

15 years ...............................

16 years ....... ........................

17 years ...............................

Girls:

12 years .......... .....................

13 years .................. .............

14 years ........ .................... ...

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years .................

Girls 12-17 years .................

Expected values:

Boys 12-17 years .................

Girls 12-17 years ............... ..

Female equivalent

Girls:

12 years .................. .............

13 years ...............................

14 years ...............................

15 years ............ .... ...... .........

16 years ...............................

17 years ... ......................... ..

,–– ——-—

Northeast IMidwest I South I West

Skeletal age in months

141.0

157.6

173.6

189.1

196.2

206.6

177.4

187.9

197.3

204.8

210.8

209.2

174.7

196.4

173.9

196.4

145.4

156.9

167.3

176.2

184.8

182.3

16.93

20.02

15.00

13.82

13.25

10.35

14.13

13.02

10.78

9.25

8.66

10.06

. . .

. . .

. . .

. . .

11.58

10.87

9.14

7.96

7.59

8.77

1.14

2.60

1.02

1.45

1.33

1.42

1.46

0.96

1.23

0.82

0.94

1.27

0.84

0.72

0.83

0.72

1.20

0.79

1.04

0.71

0.82

1.11

139.0

157.9

172.0

183.6

196.2

206.3

173.3

186.7

198.5

205.2

211.8

211.1

174.0

196.0

174.9

196.3

141.3

155.0

168.8

177.2

186.2

185.2

17.59

17.45

14.91

14.48

13.26

9.66

14.85

13.19

11.42

9.37

9.80

9.85

. . .

.-.

. . .

. . .

12.11

10.95

9.71

8.09

8.62

8.64

1.28

1.62

1.61

1.14

1.52

0.53

1.38

1.78

1.34

1.56

0.97

1.66

0.69

0.66

0.70

0.67

1.13

1.48

1.14

1.35

0.85

1.46

141.1

156.1

174.2

186.7

196.6

204.4

175.7

186.7

197.6

206.9

212.0

213.0

175.9

197.5

175.9

196.9

143.7

155.0

167.6

178.9

187.0

189.0

16.03

18.34

15.80

14.88

14.28

11.65

14.30

12.87

11.16

9.46

11.95

9.22

. . .

..-

. . .

. . .

11.70

10.68

9.47

8.18

10.54

8.18

1.62

1.32

1.87

1.02

1.04

0.72

1.35

1.03

0.81

0.74

1.22

1.40

0.91

0.96

0.91

0.95

1.10

0.86

0.69

0.64

1.08

1.24

140.2

157.8

174.7

187.6

196.4

204.3

173.9

186.4

198.5

205.4

210.5

212.9

175.3

196.6

175.0

196.9

141.9

153.4

168.8

177.4

184.5

188.4

17.20

16.32

14.66

13.20

14.37

11.95

15.58

12.64

9.69

8.45

9.17

9.32

. . .

. . .

. . .

. . .

12.71

10.46

8.24

7.30

8.04

8.25

1.38

1.16

1.16

1.41

1.36

1,40

2.39

0.87

1.47

1.02

1.15

1.20

0.83

0.86

0.83

0.87

1.95

0.72

1.25

0.88

1.01

1.06

NOTE: -f = mean skeletal age (hand-wfi~t); Sx = standard deviation of skeletal age; and s= = standard error of mean. Expected

values remove the effect of differences in the chronological age distribution with respect to skeletal age over the 12-17-year age span by

indirect adjustment.

54
Tabla 3. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by geographic region, chronological age at last birthdav, and sex: United

Standard reference, sex,

and chronological age

at last birthday

Male standard

Boys:

12 yams.., .....................................

13 years,,,, ...............oo....io.............

14vems ........................................

15y@ar$ ..............o.........................

16years ........................................

17 ymr$.., .....................................

Girlx

12years ........................................

13 years ........................................

14 veers ........................................

15ycms ........................................

16 Vears.l ....................!.................

17 Vmrs ........................................

Actual values:

BOVS 12-17 vaars ..........................

Girls 12-17 years ...........................

Expected vduas:

BOV8 12-17 yeara ..........................

Girls 12-17 veals,,, ........................

Female equivalent

Girls:

12 years ............... .........................

13yurs..o..u..u ......n........................

14 ywars ........................................

16 Vaars ........................................

16 WWS,.......................................

17 Vm’s,,,................. +........o..........

States, 1966-1970

Northeast Midwest South West

White Negro White Negro White Negro White Negro

z $~ E s? z % ~ s~ : Sj? ~ Sx ~ SF z SF

Skeletal age in months

141.1

157.4

173.4

189.6

196.6

207.3

177.0

187.S

196.8

204.8

211.1

208.3

176,0

196.4

176,0

186,6

145.0

156.8

I 66.8

176.6

185.2

IS2,6

1.24

2.63

0.82

1,63

1.44

1.24

1.33

1.20

1.27

1.07

0.99

1.13

0.99

0.S6

1,00

),86

I .08

I .00

I .0s

3.92

),67

),98

140.7

158.s

174.9

164,6

196.0

200.0

179.4

1S8.5

200.6

204.9

207.8

20S.6

172,3

196.4

173.7

196.8

147.4

157.6

171.6

176.8

1S0.8

181.6

1.56

7,66

3.06

S,38

3.40

S.88

4.S8

2.56

3.66

2.36

0.69

4.54

0.86

1.53

0.97

1.63

4.01

2.14

3.15

2.04

0.80

3.95

138.6

157.2

172.9

1B4,2

196.9

206.2

173.1

1s6.6

19B.2

204.6

211.7

211.1

174.2

195.9

174.6

196.2

I 41.1

155,2

168.4

176.2

186.4

1S6.2

1.22

1,60

1.43

1.1s

2.08

0.61

1,50

1 .9s

1.46

1.73

1.00

1.74

0.84

0.71

0.64

>.71

1.22

1.65

1.24

1.49

0.86

1.53

131.1

164.5

162.9

176.1

190.4

206.8

174.9

1s7.5

203,1

211.2

213.4

211.1

172.4

197.8

169.4

198.4

142.9

156.5

174.1

1s5.4

189.4

185.2

2.66

3,84

4.52

3.35

2.82

4.61

9.84

2.44

2.99

2.16

1.92

2.93

3.16

1.86

3.11

1.67

3.04

2.04

2.56

I .91

I .70

2.57

.

142.0

154.5

174.0

18B.5

196.8

206.1

174.9

1s6.6

198.0

206.6

212.4

213.3

177.3

197.5

175.4

197.3

142.9

155.6

16B.O

17S.6

187.8

169,3

—

1.19

1.19

2.13

1 .0s

1.14

0.92

1.33

1.13

0,50

0.69

1.51

1.30

0.92

0.86

0.91

0.88

1.08

0.94

0.42

0.60

1.34

1.15

—

139.1

159.4

174.9

181.4

196.1

199.1

177.s

186,6

196.4

207.9

211.1

212.3

172.0

197.5

172.9

196.S

145.8

155.2

166.4

180.8

186.2

167.6

5.85

4.34

3.50

1.10

1.76

2.14

3.74

1.85

2.31

1.40

1.33

4.06

2.16

1.63

2.19

1.62

3.07

I .54

1.96

1.22

1.17

3.59

139.9

157.4

174.7

187.3

197.4

203.8

172.8

166.2

198.4

205.4

210.9

213.1

175.1

196.5

175.2

198.2

140.6

153.2

168.8

177.4

184.9

189.1

1.76

1,55

1.17

1.58

1.27

1.44

2.22

0.93

1.56

1.09

1.22

0.97

0.s2

0.94

0.s2

0.94

1.81

0.77

1.33

0.94

1.07

0.B6

142.4

166.5

174.8

186,7

176.0

20B.3

182.7

188.7

198.9

206.?

204.0

209.2

174.9

196.2

173.7

197.1

150.7

157.7

170.9

176.1

175.0

182.4

7.66

12.96

4.44

41.90

57.46

46.76

57.8S

2.74

1.20

2.75

4.97

47.65

6.64

1.87

6.59

1.8S

47.74

2.29

1.03

2.3S

4.26

41.65

NOTE: S = mean skeletal age (hand-wrist) and sc = standard error of mean. Expected values remove the effect of differences in the chronological age distribution with

respect to skeletal age over the 12~i7:Year age span by hdirect adjustment.’

55
Table 4. Mean skeletal age (hand.wrist) of youths by population size in urban areas and land use In rural areas of residence, chronological ags at last birthday, and sax, with sdocted

standard errors United States, 1686-1970

,

Standard of reference, sex,

and chronological aga

at last birthday KI Urbanized areas

Urban outside urbanized

Urban areas Rural Rural-farm Rurd-nonfan

total 3 million 1.0-2.9 250,000- Lessthan 25,000 1o,oQo- 2,Wo- total 10 acres Len than

or more

10 acrat L-s than

million 999,669 25JJ,000 or more 24,666 9,966 or more 10 acres or more 10 acrm

Male standard

BOYS:

12 years ..............................

13 yet,....,,...,, ..................

14 years<,.,..........................

15 yams ..............................

16 years..............................

17 years..............................

Girls:

12 years..., ..........................

13 years..............................

14 years., ............................

15 years..............................

16 years ..............................

17 years ..............................

Actual values:

BOYS12-17 years ................

Girls 12.17 years ................

Expected values:

BOYS12.17 years ................

Girls 12-17 years ................

Female equivalent

Girlx

12 years..............................

13 years..............................

14 years..............................

15 years.,...,..,..,..,,,, ............

16 YEWS..,.,.,.., ...................

17 years..............................

Male standard

Boys:

12 years..............................

17 years..............................

Girls:

12 years ..............................

17 years., ............................

BOYS12-17 yeers .....................

Girls 12-17 years.,,,.,., ..............

140.2

157.6

173.4

187.1

196,4

205.6

176.0

186.7

19S.2

205.8

210.7

212.0

174.9

196.6

174.7

196.6

143.0

155.0

158.4

177.8

184.7

1B7,0

0.75

0.81

0.94

0.77

0.52

0.44

140.2

159.0

173.4

1BB.4

196.1

206.9

178.5

187.5

199.6

207.5

212,3

208.6

175.6

197.4

174.B

196.0

146.5

156.5

170.6

179.6

187.4

182,9

139.7

155.7

172.6

185.1

194.8

205.5

173.2

184.9

194.B

203.4

207.6

211.2

171.9

195.2

172.8

197.3

141.2

152,9

154.2

174.4

179.9

1B5.3

141.B

166.7

174.0

190.8

197.5

205.3

173.9

186.2

19B.7

206.1

212.0

215.6

176.7

198.0

176.6

197.4

141.9

154.3

169.0

176.1

187.0

191.6

2.03

1.91

4.39

0.9B

1.56

2.11

13B.6

150.3

175.5

166.3

197.1

205.6

1739

1B8.O

19B.6

206,2

211.6

213.6

175.1

197.4

174.3

196.8

141.9

157.0

169.2

17B.2

185.9

189.6

Mean skeletal age in months

137.6

163.0

172.1

1B6.2

189.1

208,3

170.5

190.4

196.7

204.1

210.3

212.6

174.9

197.1

i74.0

197.7

13B.5

169.4

155.7

175.2

184.3

188.2

138.8

160.4

168.6

162.6

197.4

202.5

171.4

166.6

199.4

204,B

208.B

209.0

177.2

193.3

176.7

194.3

139.4

154.9

170.4

176.2

181.8

182.0

141.3

155.3

173.9

185.8

196.1

201.3

172.0

186.2

168.1

2U6.4

210.7

213.3

174.8

186.3

175.9

195.6

140.0

154.3

170.1

17B.4

184.7

189.3

Standard error of the mrnn

7.46 3.27

3,31 1.40

_L2.03 7.65

6.66 3.04

2.61 3.81

2.50 2.33

140.4

156.4

173.9

185.3

196,3

m4.9

175.1

1B6.5

197.7

m5.2

212,4

210.6

174.9

196.5

175.3

196.6

143.1

154,s

167.7

177.2

1B7.6

184.6

3.40 1.78 0.82

45.54 2.37 0.65

_L-L 4.40 3.04 1.24

SO.94 1.72 0.95

2.B5 2.04 0.67

6.04 0.99 0.36

137.0

153.2

174.9

163.5

200.4

203.6

173.0

1BO.6

197.2

m3,8

211.7

20B.1

176.0

193.5

177.0

196.1

141.0

146.6

167.2

174.B

186.0

181.1

2.06

2.63

3.67

2.13

1.58

1.27

161.8

190.3

163.0

191.2

189.2

197.5

m4.7

193,6

212.0

163.B

189.0

166.7

193.1

156.2

167.5

176.0

162.6

187.0

96.17

149.91

9.01

8.14

134.1

152.6

173.3

1S4,2

197.7

204.7

176.6

1B7.1

196.0

210,7

211,2

20B,4

177.1

194,B

17s.1

194.B

143.6

156.1

166.0

1B4.7

185,3

181,4

3,04

3.52

4.66

2,56

3.49

1.57

141,6

157.4

173.6

186.2

196.2

205.3

176.3

1B8.3

197.9

205.2

212.6

211.6

174.4

197.6

174.4

197.1

143,3

167.3

167,9

177.2

187,8

185,B

1.12

1.02

1.08

1.03

0,B5

0.46

56
Table 5. Mean. standard deviation, and standard error of the mean skeletal age (hand-wrist) of vouths bv annual familv income. chronological age at last

Standard of reference, sex,

and chronological age

at last birthday

Male standard

BOYS:

12 years ..............................................

13 years ..............................................

14 years ..............................................

15 years ..............................................

16 years ..............................................

17 years ..............................................

Girls:

12 years ..............................................

13 years ............i .................................

14 years ..............................................

16 years ..............................................

16 years ..............................................

17 years ..............................................

Actual valuas:

Boys 12-17 years ................................

Girls 12.17 years .................................

Expected values:

Boys 12-17 years ................................

Girls 12-17 years .................................

Female equivalent

Girls:

12 years ..............................................

13 years ..............................................

14 years ...o..........................................

15 years ..............................................

16 years ..............................................

17 years ..............................................

-...——.

birthday, and sex: United States, 1966

I

Less than $5,000

I

$5,000-$9,999

139.5

156.2

174.0

185.1

195.6

203.9

176.3

185,3

197.5

206.3

210.9

211,6

174,5

195,8

175.5

195.8

144.2

153.3

167.5

178.3

184.9

186.2

16.34

19.27

15.90

15.42

13.91

11.18

16.31

12.37

11.45

8.71

11,88

10,60

27.28

18.04

. . .

. . .

I 3.34

10.23

9.71

7.53

10.42

9.33

2.35

2.61

2.03

1,46

0.98

1.07

1.97

0,98

1.08

0.74

1.41

1.19

1.26

0.72

1.29

0.72

1.61

0.81

0.92

0.64

1.24

1.05

139.7

159.2

174.3

186,3

195.6

205.7

173.5

187.0

196.6

205,1

211.0

211.8

174.6

195.5

174.6

196.1

141.5

158.0

I 66.6

t77:l

185.0

186.6

17.59

17.66

15.57

14.15

14.32

9.75

15.65

13.49

11.74

8.51

8.93

9,56

27.25

18.04

. . .

..-

12.76

11.25

9.95

7.35

7.83

8.42

Skeletal age in months

0.96

0.78

0.86

0.97

1.21

0.66

1.12

0,99

0.89

0.47

0.82

0.98

0.56

9.61

).56

1.62

1.91

1.83

).75

1.41

3.72

3.86

—

141.6

156.5

172.1

187.9

198.7

206.8

175.7

187.3

200.0

205,0

211.9

211.4

175.5

198.1

174.9

197.9

143.7

156.3

171.0

177.0

186.8

185.8

16.31

17.70

14.15

13.48

12.20

11.78

12.29

12.71

8.66

9.81

9.02

9.71

26.84

17.02

---

---

10.05

10.61

7.40

8.47

7.95

8.53

1.34

1.50

1.23

1.00

1.94

1.13

0:90

1.25

0.47

1.15

0.95

1.04

13.87

0.78

0.86

0.78

0.74

1.04

0.40

0.99

0.84

0.91

138.8

154.4

175.7

183.6

193.3

204.7

178.1

185,5

198.0

206.5

211.4

212.9

175.6

197.0

177.1

196.2

146.1

153.5

168.0

178.5

185.8

188.8

2.51

3.66

2.26

2.17

1.25

1.80

2.37

1.32

1.20

1.17

1.27

2.08

2.06

9.69

?.08

).68

I .94

I .09

I .02

I .01

1.12

1.84

141.3

155.8

173.9

189.3

199.9

205.7

173.2

185.0

199.3

204.1

211.3

208.7

175.6

197.9

174.8

199.0

141.2

153.0

170.3

175.1

185.6

181.7

2,28

2.42

1.49

1.81

2.64

2.51

1.39

2,20

1.09

1.50

1.19

1.66

1.40

1,00

1.39

1.02

1.13

1.82

0.93

1.29

1,05

1.45

NOTE: s = mean skeIetal age (hand-wrist); Sx = standard de~ation of skeletal we; and % = standard error of mean. Expected values remove the

effect of differences in the chronological age distribution with respect to skeletal age over the 12-17-year age span by indirect adjustment.

57
Table 6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chronological age at last birthdav. and sex: United States. 1966-1970

Standard of reference, sex, and chronological age at last birthday

Male standard

Boys:

12 years ........................................................................................

13 years ........................................................................................

14 years ............ ............................................................................

15 years .. ......................................................................................

16 years ........................................................................................

17 years ........................................................................................

Girls:

12 years ........................................................................................

13 years ........................................................................................

14 years ........................................................................................

15 years ........................................................................................

16 years ........................................................................................

17 years ........................................................................................

Actual values:

Boys 12-17 years ..........................................................................

Girls 12-17 years ...........................................................................

Expected values:

Boys 12-17 years ........................................ ..................................

Girls 12-17 years ...........................................................................

Female equivalent

Girls:

12 years ..................................................................................o.....

13 years ........................................................................................

14 years ........................................................................................

15 years ........................................................................................

16 years ........................................................................................

17 years ...............................................................................o........

Skeletal age in months

139.9

154.7

173.5

186.2

196.4

205.0

175.1

185.1

196.8

206.1

211.3

212.3

175.4

195.3

175.1

195.7

143.1

153.1

166.8

178.1

185.6

187.6

2.32

2.57

2.51

1.89

1.20

1.19

2.83

1.19

1.24

0.90

2.07

1.45

1.52

0.95

1.51

0.96

2.32

0.98

1.05

0.7B

1.81

1.28

138.5

158.8

175.1

182.3

193.5

201.3

179.4

185.8

199.0

207.0

210.2

210.4

172.6

196.7

173.3

196.0

147.4

153 .B

170.0

179.0

184.2

184.4

4.53

4.94

3.42

2.05

1.91

1.89

2.80

1.97

1.65

0.82

0.79

3.10

1.64

0.96

1.65

0.95

2.30

1.63

1.41

0.71

0.69

2.72

139.8

15B.4

175.0

186.8

196.4

205.7

173.2

186.7

196.4

204.9

210.9

211.7

174.9

195.4

174.7

195.6

141.2

155.4

166.4

176.8

184.9

186.4

0.96

0.93

0.88

1.02

1.19

0.70

1.07

1.11

0.90

0.63

0.93

1.12

0.64

0.70

0.64

0.70

0.87

0.92

0.76

0.54

0.B2

0.99

138.4

164.1

168.6

180.7

190.1

206.0

176.0

189.8

199.1

207.1

212.2

212.3

171.4

196.8

173.6

194.7

144.0

158.1

170.1

179.2

1B7.4

187.6

3.10

3.46

2.65

3.66

7.03

2.32

4.48

2.51

3.44

2,07

3.50

2.45

1.57

1.56

1.59

1.54

3.67

2.09

2.94

1.79

3.09

2.16

NOTE: Y = mean skeletal age (hand-wrist) and s= = standard error of mean. Expected values remove the effect of differences in

the chronological age distribution with respect to skeletaI age over the 12-17-year age span by indirect adjustment.

58
Table 6. Mean and standard error of the mean skeletal age (hand-wrist) of white and Negro youths by annual family income, chronological age at last birthday, and sex: United States, 1966-1 970–Con.

i 1

$10,000 or more I

Lessthan $3,000 I

$15,000 or more

White

ZEI

141.5

166.4

172.4

188.1

198.6

206.6

176.1

187.1

199.9

204.8

211,9

211.5

175.4

198.0

175.4

198.1

143.1

156.1

170.9

176.6

186.8

186.0

1.36

1.56

1.19

1,06

2.01

1.19

0.93

1,28

0,53

1.18

0.96

1,01

0.85

0.79

0.85

0.79

0,76

1.07

0.45

1.02

0.85

0.89

I I

Negro White I Negro White Negro

144.2

162.5

159.6

177.2

205.9

211.8

183,9

199.0

200.8

213.9

209.8

208.3

175.8

206.6

177.1

199.4

151.9

170.0

171.8

189.9

183.6

181.3

10.04

51.95

8.72

8.27

103.16

5.51

12.38

5.12

5.41

3.55

66,49

46.72

5.22

2.29

5.24

2.25

10.23

4.37

4.63

3.15

58.19

46.72

139.4

154.4

173.6

184.1

194.2

206.8

177.8

186.5

198.0

206.5

213.3

214.5

176.4

197.4

176.1

196.9

145.8

155.0

168.0

178.5

189”.3

190.5

Skeletal age in months

3.45

5.69

2.14

3.07

1.61

1.70

3.26

1.80

1.68

1.64

1.20

1.49

2.90

0.93

2.89

0.92

2.67

1.50

1.43

1.42

1.06

1.32

137.8

154.5

178.4

182.8

191.8

200.9

179.0

184.0

198.1

206.5

208.2

210.5

174.2

196.1

174.8

197.2

147.0

152.0

168.2

178.5

181.2

184.5

3.39

5.07

3.69

3.24

1.75

3.10

2.53

2.67

2.68

1.24

1.94

4,56

2.53

1.42

2.54

1.44

2.08

2.21

2.28

1.07

1.69

4.00

140.8

155.9

174.2

189.1

199.7

205.5

173.1

184.4

199.1

203.9

211.5

208.7

175.5

198.1

175.6

198.2

141.1

152.4

170.1

174.9

186.0

181.7

2.33

2.44

1.48

1.90

2.75

2.66

1.47

2.22

1.18

1.53

1.16

1.67

1.47

1.03

1.47

1.03

1.20

1.83

1.01

1.31

1.02

1.45

161.2

149.6

188.7

220,0

209.0

170.1

196.7

202.9

196.0

206.8

187.8

197.0

181.2

195.4

138.1

166.7

173.9

166.0

178.8

80.69

105.79

133.41

155.56

104.68

120.30

5.92

101.65

138.59

146.22

60.28

4.74

60.20

4.72

97.67

5.02

87.12

117.38

126.42

59
Table i’. Mean and standard arror of tha mean akalatal age (hand-wrist) of white and Negro youths by education of first parent, chronological age of youth at last blrthdav.

Standcrd of refarence, sex,

and chronological aW

at last birthday

Male standard

BOYS:

12yaers .........................................

13 W.3K, . .......................................

14 years ......................................

15 years ......................................

16 years .........................................

Ilyear% .........................................

Girls:

12 yaara .........................................

13 years .........................................

14 years,.,...,., .............................

15 years ......................................

16veera .........................................

17 years .........................................

Actual values:

Boys 12-17 years ...........................

Girls 12-17 years., ..........................

Expacted valuas:

Boys 12-17 years ...........................

Girls 12-17 years ............................

Femala equivalent

Girls:

12 years ......................................

13 years .........................................

14 years .........................................

15 years .........................................

16 yaars .........................................

17 veara .........................................

and sex: United States, 1966-1970

Education of parent

Less than 5 years 5-B years 9-12 years 13 years or more

Whita Negro Whita Nagro Whita Nagro White Nagro

z SF x SE z SE z Sx x SE z SF % $~ E s%

Mean skaletal age in months

140.4

156.9

174.4

187.5

197.2

206.1

174.4

1S6.7

19s.3

205.5

211.7

212.0

176.5

197,2

176.3

197.4

142.4

155.0

16s.4

177.5

166.0

1S7.O

0.79

0.97

0.79

0,77

0.B2

0.54

0.7s

0.77

0,5s

0,57

0.51

o.5a

0,39

0.41

0.3s

0.41

0.84

0.64

0.48

0.49

0.45

0.60

138,6

161.0

173.4

183.0

192.7

203.4

179.6

1S8.4

199,2

207,6

210.7

210.9

173.7

198.0

176.2

19B.7

147,6

157.4

170.2

179.9

1s4.7

1S4.9

3.12

3.19

2.09

1,21

2.93

1.42

2.36

1.39

1.75

0.81

0.92

2.15

1.29

D.97

1.30

D.96

1,94

1.16

1.50

3.70

2,s1

1.8S

—

136.C

154.!

174.8

18S.E

197.2

206.4

175.1

lSB.2

199.0

205.8

211.7

212,0

176.S

19s.7

17S.6

19s.9

143,1

157.2

170.0

177.s

186.0

1s7.0

.

0,62

1.20

0.92

0.s1

0,s4

0.56

0.93

0,s9

0,82

0,51

0.50

0.68

0.43

0.45

0.43

0.45

0.76

0.74

0.53

0.44

0.44

0.60

—

136.3

159.0

173,2

1s3.s

192.9

203.4

179.6

189.7

201.3

207.6

210.7

210,9

173.3

199.2

175,0

187.9

147.5

158.7

172.3

179.9

1s4.7

1s4.9

3.07

3.55

2.48

1.26

2.95

1.42

2.S5

1.19

1.42

0.s1

0,92

2.15

1.34

0.77

1,35

0.76

2.34

1.00

1.22

0.70

0.81

1.6s

138.S

155.1

174,6

188.2

197.5

206.0

175.0

187.9

198,6

205.6

211.5

211.7

176.4

19s,0

176.1

19S.2

143.0

158.9

16s.9

177.6

185.8

1S6.0

0.61

1.09

0.84

0.79

O,BO

0.54

0.ss

0.s2

0.66

0.52

0,52

0,64

0.41

0.42

0.41

0.42

0.72

0.6s

0.58

0.45

0.46

0.56

137.3

159.4

172.8

1S2.3

192.9

202.4

17S.8

18S.7

200.6

207.6

210,2

210.5

173.0

19s.5

174.9

197.4

146.8

157.7

171.6

179.9

1B4.2

1S4.5

2.97

3.58

2.42

1.24

2.95

1.65

2.75

1.07

1.44

0.81

0.9s

2.14

1.27

0.72

1.26

0.71

2.26

0.89

1.23

0.70

0.B4

1 .Sa

138.6

155,2

175.4

188.7

197.7

206,3

175.2

1S8.3

1s9.1

205.7

211.6

211 .s

177.7

19s.7

177.4

19s.9

143.2

157.3

170.1

177.7

1S6.9

1S6.2

0.77

1.15

0.s7

0,s1

0,62

0.55

0.96

O.BS

0,61

0.61

0.60

0.87

0.41

0.46

0.41

0.46

0.78

0.74

0.52

0.44

0.44

0.59

137.2

159.7

173.6

183.9

192.9

203,2

179.s

1S9.4

201.2

207.6

210.4

210.9

174.4

199.2

176.2

197.9

147.8

158.4

172.2

17s.9

164.4

1S4.9

3.26

3.s0

2.33

1.16

2.95

1.61

2.67

1.06

1,41

0.81

0.90

2.15

1.42

0.73

1.43

0.72

2,11

0.s9

1.20

0.70

0.78

1.8S

NOTE: Z = mean skeletal age (hand.wdst) and $X = standard error of mean. Expected values remove the effect of differences i“ the Chro”olo$cal sge distribution ~th

1.3iIpCCtto skeletal age over the 12.17.year age sprm by indfrect adjustment.
Table 8. Salactad percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family income,

chronological age at last bi;thday nd sex: United States, 1966-1970

Race, region, annual family income, and percentile

White

P75 .................................................................................................

P513.................................................................................................

P25 .................................................................................................

Negro

P75 ,.,,,, ,,.,,. .,,,.... .............................................................................

P50 .................................................................................................

P25 .................................................................................................

Northeast

P75 ........................m........................................................................

Pfjo .m...............................................................................................

P25 .................................................................................................

Midwest

P75 .................................................................................................

P51J.................................................................................................

P25 .......................m......o..o.o.............................................................

South

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

West

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

Lessthan $5,000

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

$5,000-$9,999

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

$10,000 or more

P75 .................................................................................................

P50 ............m....................................................................................

P25 .................................................................................................

Chronological aga in years at last birthday

Boys

12 years I

13 years I

14 years 15 years I16 years 17 years

154.3

140.0

127.3

154.4

134.7

126.1

154.1

142.0

127.8

153.0

137.3

123.9

155.1

141.0

128.7

155.0

138.6

127.1

154.2

138.8

126.1

153.9

137.7

127.0

155.2

142.1

127.7

170.0

158.3

144.8

172.8

163.5

151.0

172.8

159.4

143.6

169.4

159.8

146.1

171.0

157.1

144.9

169.3

158.5

146.5

171.0

157.6

144.1

171.6

159.7

147.2

169.0

159.7

144.4

Skelatal age in months

182.1

174.1

165.6

183.7

172.7

161.7

182,8

173.6

163.4

180.8

172.8

161.5

182.8

175.1

167.0

181.3

175.1

166.6

181.9

173.5

166.8

183.5

174.4

166.1

180.7

173.9

160.9

198.4

186.4

177.2

195.4

179.8

170.2

200.5

191.8

178.4

195.7

182.0

175.0

198.1

185.6

176.5

198.2

187.6

178.5

198.3

182.4

174.5

197.1

185.9

177.3

200.0

188.3

178.2

206,3

199.1

189.5

205.2

197,3

181.9

205,5

198,8

189.2

205.0

198.9

188.1

207.3

199.1

187.9

206.0

199.1

189.5

207.0

198.5

186.5

206.0

198.6

188.5

206.2

200.7

192.9

213.1

207.1

199.6

210.6

203.1

195.7

216.0

206.5

199.5

213.2

206.7

188.9

212.9

207.1

197.9

211.0

206.9

198.7

211.6

205.6

197.1

212.7

206.6

188.8

213.6

207.8

200.0

61
Table 8. Selected percentiles in the distribution of skeletal aga (hand-wrist) for youths by rata, geographic region, annual family income,

. chronological age at last birthday, and sex: Unitad States, 1966-1 970—Con.

Rata, region, annual family income, and percentile

White

P7!5.................................................................................................

P50 .................................................................................................

P25 .................................................................................................

Negro

P75 .................................................................................................

P50 .................................................................................................

Northeast

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

Midwest

P75 .................................................................................................

P5(J ........................ .........................................................................

P25 .................................................................................................

South

P75 ..................... ............................................................................

P~o .................................................................................................

P25 .................................................................................................

West

P75 .:...............................................................................................

P50 .................................................................................................

P25 .................................................................................................

Less than $5,000

P75 .................................................................................................

P51J.................................................................................................

$5,000-$9,999

P75 ..................................................................................................

P50 .................................................................................................

P25 .................................................................................................

$10.000 or more

P75 .................................................................................m...............

P50 .................................................................................................

P25 .................................................................................................

Chronological age in yeare at last birthday

Girls (female ecmivalant)

12yaarsl 13yaarsl 14years I l!5yearsl 16yearsl 17 years

152.1

142.7

134.4

159.6

146.8

138.8

153.9

144.3

137.9

49.6

40.7

34.4

55.4

45.3

34.5

52.3

42.6

34.1

56.2

45.4

35.0

51.7

42.3

134.3

152.1

142.8

135.7

166.8

156.2

145.1

166.4

156.9

146.9

167.3

157.4

145.7

167.5

157.4

145.3

166.9

155.2

144.8

165.7

153.2

145.1

163.5

152.1

145.4

167.4

157.0

144.5

167.2

157.5

145.8

Skeletal age in months

176.4

170.2

162.3

180.0

171.2

165.0

177.4

169.2

161.7

178.5

171.5

162.4

176.0

170.2

162.6

175.9

169.4

162.6

176,4

168,9

162.3

175.9

167.9

161.2

177.8

172.1

163.8

186.2

177.9

169.0

187.8

181.1

173.0

185.3

177.5

167.9

187.0

177.5

168.3

190.1

179.2

172.4

186.2

177.4

168.9

188.2

178.0

171.7

185.9

177.4

168.8

185.4

178.4

167.8

197.4

187,4

179.0

196.3

185.9

173.7

196.3

185.3

175.4

198.4

187.6

178.4

200.1

188.2

179.6

192.7

189.4

179.6

197.2

187.3

179.6

195.2

186.4

175.9

197.6

187.2

179.0

198.2

189.0

177.3

197.3

187,4

172.9

193,9

185.6

173.0

200.0

187.2

175.2

200.2

189.7

184.5

199.1

191.2

178.5

198.2

189.6

178.6

199.5

189.2

177.5

197.6

188.2

174.7

62
Table 8. Selected percentiles in the distribution of skeletal age (hand-wrist) for youths by race, geographic region, annual family income,

chronological age at last birthday, and sex: United States, 1966-1 970–Con.

Race, region, annual family income, and percentile

White

P75 .................................................................................................

P5Q .................................................................................................

P25 .................................................................................................

Negro

P75 .................................................................................................

P50 .................................................................................................

Northeast

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

Midwest

P75 .................................................................................................

P50 ...............m.................................................................................

P25 .................................................................................................

South

P75 ....................%............................................................................

P50 .................................................................................................

P25 .................................................................................................

West

P25 .................................................................................................

Less then $5,000

P75 .................................................................................................

P50 .................................................................................................

P25 .................................................................................................

$5,000-$9,999

P5~ .....m...........................................................................................

P25 ............m...i................................................................................

$10,000 or more

P75 .................................................................................................

P5(J.................................................................................................

P25 .................................................................................................

Chronological age in years at last bir;hday

Girls (male standard)

12 years 13 years I

14years 15 years 16 years 17 years

Skeletal age in months

184.1

174.7

165.9

190.6

178.8

170.8

185.9

176.3

169.9

181.6

172.7

165.7

186.9

177.3

166.0

184.3

174.6

165.2

187.2

177.4

167.0

183.7

174.3

165.6

184.1

174.8

167.7

196.8

187.2

177.1

196.4

187.9

178.9

197.3

188.4

177.7

197.5

188.4

177.3

196.9

186.8

176.8

195.7

185.2

177.1

194.5

184.1

177.4

197.4

188.0

176.5

197.2

188.5

177.8

204.9

199.2

193.3

207.5

200.2

195.0

205.4

198.8

192.7

206.5

200.5

193.4

204.7

199.2

193.6

204.6

198.9

193.6

204.9

198.6

193.3

204.6

197.9

192.2

205.8

201.1

194.8

211.8

205.9

198.7

212.8

208.1

202.0

211.2

205.9

197.9

212.0

205.5

198.2

214.1

207.1

201.4

211.8

205.4

198.6

212.8

206.0

200.7

211.6

205.4

198.5

211.3

206.4

197.8

220.3

212.3

207.0

219.3

211.6

202.7

219.3

211.2

204.3

220.9

212.4

206.4

222.1

212.8

207.4

216.7

213.4

207.4

220.1

212.2

207.4

218.8

211.9

204.6

220.4

212.1

207.0

220.8

213.0

205.3

220.2

212.3

201.9

217.9

211.4

202.0

222.0

212.1

204.1

222.2

213.7

210.5

221.1

215.2

206.5

220.8

213.6

206.6

221.5

213.2

205.5

220.4

212.8

203.7

63
Table 9. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of white and Negro youths by chronological acre in years

at la!

Standard of reference, sex,

and chronological age

at last birthday

Mele standard

Boys:

12 years ...............................

13 years ........... ....................

14 years ...............................

15 years ........................... ....

16 years ...............................

17 years ...............................

Girls:

12 years ...............................

13 yaars ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years ..................

Girls 12-17 years .... ..............

Expactad values:

Boys 12-17 yaars ......... .........

Girls 12-17 yaars ..................

Female equivalent

Girls:

12 years ..................... ..........

13 yaars ...............................

14 years ...............................

15 years ...............................

16 yaars ...............................

17 yaars ...............................

Male standard

Boys:

12 years .............................. .

17 years ...............................

Girls:

12 yaars ...............................

17 years ...............................

Boys 12-17 years ............... ........

Girls 12-17 years .......................

]irthday and sex, with selacted standard errors: U nitad States; 1966-1970

-.

Radius Ulna Capitate Hamate Triquetral

Whita Nagro White Negro Wh ita Negro Wh ita Nagro White Negro

Mean skeletal age in months

139.9

156.7

173.7

186.9

19B.O

207.5

173.2

185.7

197.8

208.5

214.2

217.0

175.4

197.6

175.2

197.8

141.2

153.7

167.8

181.8

190.2

194.0

0.66

0.51

0.73

0.41

0.42

0.37

139.0

160.3

171.8

181.9

192.8

204.0

177.9

186.5

199.2

209.5

213.9

217.7

172.4

198.4

174.2

197.1

145.4

154.5

169.2

183.5

189.9

194.7

2.95

1.81

2.60

0.92

1.15

1.01

140.0

156.1

173.2

186.3

195.0

202.2

172.8

185.2

196.6

203.7

206.6

208.4

172.5

191.2

172.4

191.4

140.8

153.2

166.9

174.0

179.6

181.4

0.64

0.64

0.80

0.37

0.52

0.39

139.5

160.6

172.3

181.1

190.6

199.3

177.7

186.6

196.2

203.8

205.2

208.2

170.6

192.0

171.7

190.8

145.7

154.6

166.3

174.2

177.3

181.2

141.0

155.7

168.2

175.6

178.6

184.9

168.2

175.9

182.0

188.0

185.4

191.6

157.8

173.3

157.5

173.2

136.2

143.9

150.0

157.0

153.4

161.6

140.1

155.3

164.2

171.4

167.1

184.6

168.2

175.2

178.1

192.0

192.0

156.0

173.1

158.1

173.6

136.2

143.2

146.1

162.0

162.0

Standard error of the mean

142.1

156.3

168.8

176.1

179.6

185.3

169.1

176.5

181.8

188.7

183.2

191.5

158.4

173.8

158.2

173.8

137.1

144.5

149.8

157.7

151.2

161.5

2.87

0.98

2.48

0.81

1.36

0.72

0.70

1.84

0.66

60.59

0.81

0.50

2.75

41.73

2.01

96.00

2.47

1.26

0.65

1.75

0.63

85.66

0.82

0.49

141.4

157.1

165.4

173.1

170.3

184.9

169.1

176.2

179.0

192.0

192.0

157.4

174.0

158.9

174.2

137.1

144.2

147.0

162.0

162.0

2.75

41.79

2.17

96.00

2.48

1.49

140.8

154.8

167.8

175.2

178.6

185.7

167.3

174.9

181.8

188.4

183.1

191.6

157.3

172.4

157.0

172.5

136.2

141.9

149.8

156.4

151.1

161.6

0.73

1.72

0.66

60.59

0.82

0.51

139.5

156.2

164.0

171.7

167.5

185.1

168.4

174.8

178.0

192.0

192.0

156.1

172.8

157.8

172.8

136.5

141.8

145.0

162.0

162.0

2.70

41.81

2.21

135.76

2.47

1.49

64
Table 9. Mean bone-specific skalatal agesfor the 31 individual hand-wrist bones of white and Nemo youths by chronological age in years

at last birthdav and sex, with selected standard errors: Uni*~~ Stat= 19-66-1970—COn.

Standard of raference, sex,

and chronological age

at last birthday

Male standard

Boys:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Girls:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years..................

Girls 12-17 Years..................

Expected valuas:

BOYS12-17 years..................

Girls 12-17 years..................

Female equivalent

Girls:

12 years ...............................

13 yeers ...............................

14 yaars ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Male standard

Boys:

12 years ...............................

17 years ...............................

Girls:

12 years ...............................

17 years ...............................

BOYS12-17 years.......................

Girls 12.17 years .......................

140.6

155.0

167.7

175.0

178.1

185.4

167.3

174.7

181.3

187.9

187.7

191.2

157.1

172.3

157.0

172.4

136.2

141.7

149.3

156.4

156.0

160.2

0.70

1.78

0.60

60.47

0.74

0.50

139.3

157.0

164.6

171.5

167.0

1B5.O

16B.9

175.5

177.5

192.0

156.4

173.0

157.8

172.5

137.0

142.5

144.5

161.0

2.56

41.81

1.90

2.26

1,21

139.2

164.1

167.4

175.5

178.3

186.3

166.6

174.6

181.0

187.6

187.3

190.4

156.6

172.0

156.3

172.0

134.6

142.6

149.0

156.2

155.6

159.4

0.59

1.77

0.60

42.59

0.76

0.47

Trapazium Trapezoid Metacarpal I

White Nagro Whita Negro White Negro

Mean skeletal age in months

137.6

156.1

163.4

171.3

167.3

183.9

167.4

175.2

178.4

‘190.6

192.0

155.0

173.0

156.8

172.8

135.4

143.2

146.4

159.6

161.0

138.3

154.2

167.7

175.3

178.5

185.2

166.7

175.1

181.0

188.6

18B.5

192.0

156.3

172.3

156.0

172.2

134.8

142.1

149.0

156.6

156.5

161.0

137.6

155.7

162.8

171.3

167.1

185.1

167.1

174.2

178.3

191.3

192.0

154.9

172.5

156.6

172.9

135.1

141.1

146.3

159.4

161.0

Standard error of the mean

2.87

41.66

2.23

135.76

2.31

1.38

0.59

1.77

0.61

42.93

0.77

0.41

2.83

41.81

2.25

135.76

2.37

1.41

139.0

154.7

168.0

175.5

178.2

185.3

167.0

175.0

181.2

188.4

188.4

192.0

156.6

172.3

156.3

172.2

135.0

142.0

149.2

156.4

156.4

161.0

0.61

1.77

0.59

42.93

0.79

0.38

137.4

155.6

163.2

170.8

166.0

185.1

165.6

174.5

179.7

191.3

192.0

154.7

172.3

156.9

173.2

134.3

141.5

147.0

160.0

161.0

2.97

41.81

2.04

135.76

2.44

1.52

138.8

155.0

169.6

176.9

179.8

183.4

170.0

177.2

181.3

185.1

185.5

185.8

160.2

175.3

160.0

175.5

138.0

145.2

149.4

154.1

154.5

154.8

0.59

0.43

0.68

0.17

0.37

0.42

137.3

158.0

167.6

172.9

174.7

182.4

172.0

178.8

179.0

186.0

186.0

186.0

159.4

176.5

160.4

175.5

140.0

146.8

147.0

155.0

155.0

155.0

2.62

1.95

1.61

58.81

1.81

0,97

65
Table 9. Mean bone-specific skeletal agesfor the 31 individual hand-wrist bones of white and Negro youths by chronological age in years

at last birthday and sex, with selected standard errors: United States. 1966-1970-Con.

Standard of reference, sex,

and chronological age

at last birthday

Male standard

Boys:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Girls:

12 yeare ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years..................

Girls 12-17 years ..................

Expected values:

Boys 12-17 years..................

Girls 12-17 years ..................

Female equivalent

Girls:

12 yaars ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Male standard

Boys:

12 years ...............................

17 years ...............................

Girls:

12 yaars ...............................

17 years ...............................

Boys 12-17 years .......................

Girls 12-17 years .......................

Metacarpal I I Metacarpal I I [ Metacarpal IV

White I

Negro White Negro White Negro

138.6

154.9

171.6

182.7

188.5

196.0

171.4

183.2

194.2

198.4

203.2

204.5

165.3

184.5

165.2

184.6

139.4

151.2

164.2

168.4

174.2

175.5

0.62

1.08

0.79

1.42

0.47

0.43

137.6

159.4

169.9

177.2

183.4

195.2

173.6

184.5

193.5

201.4

204.2

198.6

164.7

184.9

165.7

183.8

141.6

152.5

163.5

171.4

175.2

168.6

3.01

2.52

1.89

99.28

1.46

1.07

139.4

155.5

171.8

182.2

188.2

194.2

171.9

182.7

192.8

196.4

200.2

200.4

165.1

183.5

165.0

183.7

139.9

150.7

161.8

166.4

170.2

170.4

0.62

0.91

0.74

1.35

0.39

0.44

White I Negro I White I Negro

Mean skeletal age in months

137.9

160.1

170.2

177.3

182.0

194.2

175.0

183.8

191.5

199.6

200.3

200.0

184.7

184.3

165.7

183.0

142.5

151.8

160.5

169.6

170.3

170.0

139.2

155.4

171.9

182.1

188.0

193.7

171.6

182.4

192.8

196.7

200.3

200.7

165.0

183.5

164.9

183.7

139.6

150.4

162.2

166.7

170.3

170.7

137.9

160.6

170.5

177.4

182.2

192.0

174.1

184.5

190.5

200.5

200.6

198.6

164.5

184.1

165.4

182.9

142.1

152.5

159.5

170.5

170.6

168.6

Metacarpal V I Pisiform

Standard error of the mean

139.7

155.8

172.1

182.8

190.0

196.6

171.9

183.3

194.6

199.1

203.1

205.1

166.4

185.6

166.2

185.8

139.9

151.3

163.2

169.1

173.2

176.1

2.95

2.20

1.84

63.29

1.30

0.94

0.66

0.91

0.74

1.19

0.37

0.45

2.93

2.14

1.73

99.28

1.29

0.94

0.67

1.10

0.72

0.97

0.41

0.36

138.3

160.2

171.3

178.6

184.0

192.8

175.4

184.2

192.3

201.3

202.7

204.8

165.6

185.2

166.9

184.3

143.4

152.2

161.2

171.3

172.7

175.7

2.95

1.96

2.06

102.45

1.17

0.94

141.4

155.6

167.7

174.8

179.1

185.3

167.1

174.8

182.5

187.0

187.3

192.0

158.0

172.9

157.8

172.8

135.6

141.6

150.5

155.0

155.3

160.0

0.69

1.98

0.60

0.53

0.47

139.5

157.6

163.8

171.6

164.6

186.9

166.7

174.7

178.9

192.0

192.0

157.5

172.2

159.4

172.8

135.4

141.7

146.9

160.0

160.0

2.49

42.75

2.29

135.76

1.57

1.48

66
Table 9. Mean bone-specific skeletal agesfor the 31 individual hand-wrist bones of whita and Negro youths by chronological age in years

at last birthday and sex, with selected standard errors: United States, 1966-1970–Con.

Standard of refarence, sex,

and chronological age

at last birthday

Male standard

Boys:

12 yaars ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 yeers ...............................

17 yeara ...............................

Girls:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years..................

Girls 12-17 years ..................

Expected valuas:

Boys 12-17 years..................

Girls 12-17 years ..................

Femala equivalent

Girls:

12 years ...............................

13 years ...............................

14 years ...............................

16 years ...............................

16 yaars ...............................

17 years ...............................

Male standerd

Boys:

12 years ...............................

17 years ...............................

Girls:

12 years ...............................

17 years ...............................

Boys 12-17 years .......................

Girls 12-17 yaars .......................

Adductor Flexor Proximal Proximal Proximal

sesamoid sesamoid phalanx I phalanx I I phalanx Ill

I

Whita I

Negro White

159.7

164.7

170.4

175.5

178.6

183.4

169.4

174.3

179.4

180.1

180.8

184.8

168.8

173.6

168.7

173.7

137.4

142.3

147.4

148.1

148.8

152.8

0.55

1.36

0.63

2.07

0.37

0.35

159.9

167.0

169.9

172.2

169.0

184.4

172.3

175.0

174.8

178.8

184.8

186.3

168.4

174.5

169.2

173.6

140,3

143.0

142.8

146.8

152.8

154.3

1.14

58.91

1.54

72.21

1.23

1.32

165.4

168.4

172.0

176.0

178.7

185.0

171.6

175.9

180.6

180.5

184.0

186.3

172.3

175.5

172.0

175.6

139.6

143.9

148.6

148.5

152.0

154.3

0.67

2.13

0.55

2.05

0.42

0.43

I I I

Negro White Negro White I Negro White

Mean skeletal age in months

163.9

169.1

172.5

172.4

167.6

186.9

174.6

175.2

176.5

192.0

184.8

190.5

170.8

176.4

172.3

175.8

142.6

143.2

144.5

161.0

152.8

159.5

140.8

157.0

172.9

183.7

189.1

198.8

174.5

184.5

195.7

202.8

206.5

207.7

165.8

185.6

165.6

185.9

141.5

152.5

165.7

173.8

178.5

179.7

139.4

160.7

171.3

175.8

183.6

196.4

177.3

186.9

193.7

206.7

206.5

208.6

165.0

187.0

166.5

185.6

144.3

154.9

163.7

178.7

178.5

180.9

Standard error of the mean

2.17

59.94

1.71

95.27

1.59

1.06

0.64

1.22

0.69

1.21

0.46

0.50

3.29

2.96

1.89

46.66

1.60

1.00

141.0

157.5

172.5

183.2

188.4

195.9

174.9

183.4

193.1

198.6

201.8

202.9

165.2

183.7

164.9

184.0

141.9

150.7

163.0

168.6

171.8

172.9

0.66

1.17

0.67

1.16

0.48

0.44

138.2

160.6

170.5

176.3

180.3

194.2

176.3

185.9

192.1

202.2

202.6

204.0

163.7

186.0

165.8

184.8

143.3

152.9

161.2

172.2

172.6

174.0

3.00

1.87

1.80

45.61

1.73

1.11

141.0

157.8

172.6

183.4

187.9

196.1

175.1

183.6

193.7

199.0

202.4

203.3

165.4

184.3

165.1

184.5

144.0

151.6

163.7

169.0

173.4

174.3

0.63

1.18

0.67

0.86

0.46

0.41

Negro

138.3

161.0

170.8

176.8

180.6

194.3

177.1

185.9

192.7

202.6

202.6

204.0

164.0

186.3

165.9

185.0

145.1

153.9

162.7

173.6

173.6

176.0

2.90

1.85

1.95

79.00

1.70

1.19

67
Table9. Mean bone-specific skeletal agesforthe31 individual hand-wrist bones oftiite and Negro youths bychronologiml a@ in years

at Iastbirthdav andsex, with selected standard errors: United States.1966-1970 –Con.

Standard of reference, sax,

.nd chronological age

at last birthday

Male standard

Boys:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Girls:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Actual values:

Boys 12-17 years., ................

Girls 12-17 years ..................

Expected values:

Boys 12-17 years..................

Girls 12-17 years ..................

Female ecruivalent

Girls:

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

Male standard

Boys:

12 years ...............................

17 years ...............................

Girls:

12 years ...............................

17 years ...............................

Boys 12-17 years .......................

Girls 12-17 years .......................

Proximal

phalanx IV

E

141.0

157.6

172.9

183.4

188.4

195.5

175.4

184.0

193.6

198.7

202.4

203.0

165.3

184.5

165.0

184.8

144.2

152.0

163.6

168.7

173.4

174.0

0.68

1.22

0.67

0.80

0.46

0.40

138.4

161.1

170.6

176.6

180.4

193.3

177.8

186.3

192.3

203.0

202.8

204.0

163.5

186.8

165.5

185.4

145,8

154.3

162.3

174.0

173.8

176.0

3.09

1.89

1.85

45.61

1.94

1.13

Proximal Middle Middle

phalenx V phalanx II phalanx I I I

White Negro White Negro White I

Negro

141.2

157.5

172.5

183.3

188.0

195.7

175.7

183.9

193.4

199.6

202.2

203.4

165.1

184.6

164.9

184.8

143.7

151.9

162.4

168.4

173.1

173.7

0.68

1.25

0.65

0.70

0.46

0.44

Mean skeletal age in months

138.8

161.6

171.1

177.0

181.3

192.4

177.4

186.4

193.2

202.8

202.8

204.0

164.0

186.7

165.6

185.3

145.4

154.4

162.2

173.4

173.4

174.0

141.9

157.5

172.6

182.6

188.2

195.2

175.1

184.1

192.8

199.2

202.3

202.9

165.5

183.9

165.3

184.0

143.1

152.1

162.6

170.1

172.4

173.4

139.8

160.9

170.3

176.1

181.9

193.8

176.8

185.2

191.0

200.3

202.4

204.0

164.4

185.2

166.1

184.6

144.8

153.2

160.0

170.6

172.6

175.0

Standard error of the mean

3.07

1.95

1.71

45.61

2.02

1.12

0.65

1.01

0.70

0.68

0.50

0.39

2.88

2.19

1.80

102.00

1.89

0.99

141.8

157.6

172.8

183.1

188.0

195.6

175.3

184.4

193.5

198.9

201.7

203.0

165.8

184.4

165.6

184.5

142.4

152.4

162.5

169.4

172.7

174.0

0.63

0.85

0.64

0.66

0.49

0.41

140.1

161.0

170.4

176.8

183.6

194.9

176.8

185.2

192.1

200.3

202.2

204.0

165,3

185.7

166.7

185.1

144.7

153.2

161.1

171.3

173.0

175.0

2.85

1.91

1.61

102.00

1.85

0.96

Middle

phalanx IV I~~

White I Negro

141.1

157,1

172,8

182.8

187,9

195.0

174,9

184.4

193.2

198.7

202,4

203.0

165.4

184.2

165.2

184.4

141.9

152.4

162.2

169.4

173.4

174.0

0.66

0.93

0.69

0.67

0.47

0.42

139.1

160.8

169.5

176.2

183.0

195.6

177.1

185.6

192.3

200,1

202,0

204.0

164.7

186.1

166.3

185.2

145.1

153.6

161.3

171.1

173.0

175.0

2.95

2.16

1.63

79.00

1.78

1.02

68
Table 9. Mean bone-specific skeletal agesfor the 31 individual hand-wrist bones of white and Negro youths by chronological age in years

at last birthdav and sex. with selected standard errors: Unit~~ States. 1966-1970—COn.

Standard of reference, sex,

and chronological age

at last birthday

Male standard

Boys:

12 years ......................

13 years ......................

14 years ......................

15 years ......................

16 years ......................

17 years ......................

Girls:

12 years ......................

13 years ......................

14 years ......................

15 years ......................

16 years ......................

17 years ......................

Actual values:

Boys 12-17 years.........

Girls 12-17 years .........

Expected valuas:

Boys 12-17 years.........

Girls 12-17 years .........

Female equivalent

Girls:

12 years ......................

13 years ......................

14 years ......................

16 years ......................

16 years ......................

17 years ......................

Male standard

Boys:

12 years ......................

17 years ......................

Girls:

12 years ......................

17 years ......................

BOYS12-17 years ..............

Girls 12-17 years ..............

---- ._..., —.—

Middle Distal Distal Distal Distal Distal

phalanx V phalanx I phalanx II phalanx Ill phalanx IV phalahx V

1 I I I

White Negro White Negro Wh lte Negro White Negro White Negro White Negro

Mean skeletal aga in months

141.4

157.3

172.6

182.9

187.8

194.8

175.1

183,9

192.7

198.5

202.2

202.9

165.4

183.6

165.2

183.8

143.1

151.9

162.4

168.5

172.2

172.9

0.64

0.99

0.71

0.72

0.49

0.40

139.8

160.4

169.3

176.4

183.2

193.8

176.3

185.6

192.0

199.7

202.2

204.0

164.4

185.5

166.1

184.7

144.3

153.6

161.0

169.7

172.2

174.0

140.0

155.7

168.7

176.7

180.9

184.8

170.9

178.4

183.2

186.8

187.2

185.8

159.7

176.1

159.4

176.2

138.9

146.4

151.1

153.8

154.6

152.8

1

2.85 0.66

2.38 0.92

1.80 0.64

79.00 0.84

1.81 0.40

1.04 0.34

138.7

156.4

165.7

170.0

173.4

183.4

169.9

178.1

183.9

190.0

186.0

191.0

157.8

176.5

159.9

176.6

137.9

146.1

151.4

160.0

153.0

161.0

2.91

2.32

2.00

75.07

1.92

1.38

140.3

156.0

169.2

176.6

180.5

185.2

171.0

178.7

183.6

186.7

187.2

185.8

160.2

176.3

159.8

176.3

139.0

145.4

151.6

154.7

‘155.2

153.8

137.6

157.6

165.0

169.8

172.6

181.0

170.4

178,8

184.0

190.9

185.9

190.9

157.5

176.6

160.2

176.4

138.4

145.9

152.0

160.7

153.9

160.7

140.3

155.7

169.0

176.2

180.0

184.8

170.6

178.3

182.1

186.7

187.4

185.8

160.6

175.9

159.6

176.0

138.6

146.3

150.1

154.4

155.4

152.9

137.7

157.8

165.5

170.0

172.5

181.3

170.6

178.6

182.6

191.0

185.9

191.0

157.7

176.5

160.0

176.1

138.6

146.6

150.6

161.0

152.9

161.0

Standard error of the mean

0.65

0.79

2.80

1.90

0.64

0.85

0.67 2.06 0.61

0.90 75.07 0.85

0.38

0.36 L_1.70 0.33

1.44 0.36

2.81

2.03

1.89

75.07

1.68

1.43

140.6

155.9

169.2

175.8

179.0

183.8

170.4

176.4

181.1

185.7

186.0

185.9

159.6

175.2

159.3

175.2

138.4

144.4

149.1

152.8

153.0

152.9

0.66

0.60

0.58

0.07

0.41

0.43

137.9

157.5

166.0

169.9

173.0

181.8

170.6

176.9

178.6

186.0

186.0

186.0

157.8

174.9

160.0

175.0

138.6

144.9

146.6

153,0

153.0

153.0

2.90

1.76

1.98

93.00

1.68

1.28

140.5

156.0

169.0

175.6

179.3

183.6

170.4

176.6

181.3

185.7

186.0

185.9

159.6

175.3

159.3

175.3

138.4

143.6

149.3

153.7

154.0

153.9

0.66

0.64

0.62

0.10

0.41

0.44

138.0

157.3

166.0

170.2

173.4

181.1

170.5

176.9

178.5

186.0

186.0

186.0

157.9

I 75.0

160.0

175.2

138.5

143.9

145.5

I 54.0

I 54.0

I 54.0

2.97

2.11

2.01

33.00

1.57

1.31

69
Table 10. Mean bone.specific skeletal agesfor the 31 individual hand-wrist bones of youths by wographic region, chrmolcqical age in years at last birthdav. and sex, with selmtnd ttanckrd

Standard of reference, sex, and chronological a~

at last birthday

Male standard

Expected values:

BOYS12.17 yean .........................................................................

Girls 12.17 years .........................................................................

Ma[e standard

errors: United States. 1966-1970

North.

east

140.4

157.2

173.1

189.0

196.4

m9.4

176.7

166.6

197.8

207.4

215.6

216.6

174.8

196.0

173.9

197.3

144.4

154.6

167.8

180.4

192.6

193.6

1.19

0.78

1.40

0.77

0.94

0.81

Mean skeletal age in months

139.2

157.8

172.2

163.1

196.4

207.6

172.3

186.3

197.4

208.4

213.s

217.3

174.2

197.1

175.1

197.4

140.3

154.3

167.4

181.8

169.8

I 84.3

1.48

0.67

1.65

0.47

0.74

0.67

140.3

166.4

173.8

186.7

197.2

m5.5

174.5

166.0

197.9

210.1

214.2

216.9

176.0

198.5

176.2

198,1

142.5

154.0

167.9

164.1

190.4

193.9

139.6

157.2

174.9

167.7

197.6

206.2

172.6

184.3

196.9

208.3

213.4

217.5

175.6

197.6

175.1

196.1

140.6

152,3

168.9

181.6

189.4

194.3

1.88 1.35

0.92 1.56

1.43 2.78

0.77 0.73

0.93 0.93

0.97 0.89

140.2

157.2

172.9

188.5

195.2

202.7

176.7

165.6

196.8

203.2

m7.6

208.6

171.6

t91.9

170.8

191.0

144.7

153.6

167.6

173.4

180.6

18t.6

139.2

157.0

171.6

162.9

194.0

202.3

171.8

185.5

196.4

203.6

m6.7

208.8

171.8

190.9

172.6

191.2

139.8

153.5

166.8

174.2

179.7

161.8

141.5

155.8

173.6

1s5.4

194.0

ml.0

174.2

166.0

196.5

204.6

205.6

207.2

173.4

191.6

173.4

191.4

142.2

154.0

167.0

175.6

178.2

180.2

139.3

156.9

173.9

187.1

184.6

201.6

171.5

164.4

196.7

203.4

m5.6

206.6

172.5

191.0

172.2

191.7

139.6

152.4

167.4

173.6

176.2

181.6

Standard error of the mean

1.13

0.48

1,6a

0.91

1.01

0.66

1.53

1.34

1.75

0.48

1.04

0.75

1.69

0.47

1.49

0.83

1.03

0.57

1.24

1.25

2.70

0.67

0.96

0.51

Capitate

141.2

155.1

166.5

176,6

177.9

180.4

170.2

177.6

182.1

164.9

192.0

191.2

157.4

175.2

157.2

173.6

138.2

145.6

160.1

152.9

162.0

161.2

1.33

41.01

2.06

0.83

1,66

O.oa

140.1

156.3

167.2

173.2

177.7

191.2

167.9

175.5

181.3

190.9

192.o

192.0

157.1

172.9

157.5

173.0

135.9

143.5

148.3

160.8

162.o

162.0

1.34

95.62

1.63

[35.76

1.74

1.19

141.7

164.2

166.7

174.3

774.2

185.6

166.6

176.0

178.6

184.2

189.7

167.2

172.7

157,8

173.1

136.2

143.0

146.6

152.2

156.7

1,66

2.42

0.98

1.41

0.72

140.7

167.3

168.6

176.2

177.1

184.4

166.7

175.4

184.1

187.2

183.7

192.0

166,6

172.6

167.8

173.3

135.4

143.4

162,1

166.2

161.7

162.0

1.66

41.34

1.92

96.00

1.36

1.43

70
Table 10. Mean, bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological age in years at last birthday, and sex, with selected

standard errow United States, 1966-1970—Con.

Hamate

*

tral I Lunate

North.

east

Scaphoid Standard of reference,

sex, and chronological

w at last birthday T

South West

I

South West I

North- Mideast wtst

Mean skeletal age in months

Midwest ‘outhI ‘“t

Male stnndard

BOW:

12 years.......................

13 years.......................

14 yaws .......................

16 yours..,....................

16 years.......................

17 Ynnrs.......................

Girls:

12 veals.., ....................

13 year,..,,.., ...............

14 years..,..,., ...............

16 years.......................

16 years,..,, ..................

17 years.......................

Actual VdU9S:

BOVI 1217 yews. ........

Girl: 1217 years .........

Expncted VdUOS:

BOY* 12-17 years .........

Girls 12-17 years .........

Female Equivalent

Girls:

12 years.......................

13 years.......................

14 Yearn .....................!.

16 Yearn .........!............

16 Boom,,,.,..................

17 vets .......................

Male standard

Boys:

12 years,.,.,.,., ..............

17 yaers.......................

Girls

12 years.......................

17 years.......................

Boys 12.17 yeers ..............

Girl] 12.17 yOllr$... ............

142.0

156.0

16B.B

177.2

176.1

lB1 .0

170.8

177.8

182.2

7B4.7

192.0

191,2

157,8

176.6

157.B

174.3

13B,8

145.6

150.2

152,7

162.0

161.2

1.26

40.99

1,77

0.83

1,69

0,69

139.6

155.2

166.6

172.6

177.7

190.8

167.4

174.3

180.7

191.5

192.0

192.0

155.4

172.3

157.0

172.3

136.2

141.3

146.7

160.5

161.0

161.0

136.6

154.3

165.8

172.B

176.8

192.0

165.2

174.1

179.7

191.5

192.0

192.0

155.6

171.6

156.3

171.9

134.2

142.1

147.7

160.5

161.0

161.0

139.5

153.2

165.6

173.6

175.0

184.6

167.0

174.3

178.6

184.2

1B7.5

155.8

171.8

156.5

172.1

136.0

142.3

146.6

152.2

156.0

138.B

156.1

168.7

176.8

177.2

167.1

165.B

174.0

183.4

183.9

187.7

157.7

171.5

156.7

172.0

133.9

142.o

151.4

151.9

156.4

141.0

156.B

167.6

173.6

178.7

192.0

186.3

176,5

181.B

180.9

192.0

192.0

167.7

173.4

158.3

173.7

136.3

144.5

149.B

160.8

162.0

162.0

1.29

96.00

1.17

135.76

1.74

0.94

143,0

154.9

167,1

175.2

174.1

186.1

169.7

175,2

178.4

192.0

169.7

167.7

173.2

15B.4

173.7

137.7

143.2

146.4

162.0

15B.7

1.%

2,28

1.29

1.46

0.97

142.4

15a.1

169.8

177.4

179.9

184.5

188.2

176.3

184.0

188.0

160.5

192.0

159.7

173.4

158.6

173.8

136.2

144.3

152.0

157.0

14B.5

162.0

1.34

41.33

1.88

135.76

1.36

1.46

141.3

155.3

167.9

176.7

177.8

183.4

169.2

176.4

181.2

164.4

192.0

190.9

157.5

174.0

156.8

172.6

136.7

143.4

149.2

152.4

162.0

160.9

138.7

165.6

166.3

172.1

177.7

192.0

187.3

174.3

181.8

190.8

192.0

192.0

156.4

172.1

157.0

172.3

136.1

141.3

149.8

160.8

162.0

162.0

141.4

163.6

166.3

174.5

173.2

1B6.1

167.4

174.5

178.5

192.0

1B6.9

156.7

172.0

157.3

172.S

136.1

141.5

145.5

162.0

156.9

140.4

155.7

166.8

176.1

177.9

164.6

166.5

174.7

164.o

186.4

180.6

192.0

158.1

172.1

157.4

172.5

135.5

141.7

152.o

156.4

146.6

162.0

140.0

164.5

168.1

176.1

176.7

183.4

168.7

176.2

181.4

184.4

192.0

189.8

156.6

173.8

156.6

172.7

136.8

143.2

149.4

152.4

161.0

158.8

141.5

154.4

166.2

173.9

173.6

185.2

167.9

175.0

17B.O

192.0

1B8.1

156.9

172.2

157.2

172.3

136.4

142.0

146.0

161.0

1’67.1

1.36

2.35

1.16

1.25

0.72

140.7

157.1

166.5

175.8

176.8

184.2

166.2

173.9

183.1

163.0

187.3

156.3

171.6

157.3

172.4

135.2

140.9

151.1

151.0

155.6

1.73

41.30

1.54

1.35

1.40

139.2

154.1

167.9

176.S

176.8

162.5

166.2

176.5

161.2

184.4

190.0

158.4

173.8

156.0

172.6

136.2

144.5

149.2

152.4

159.0

1.13

41.55

1.66

1.52

1.75

0.87

8ta”dard error of the mean

1.29 1.33

41.46 96.00

1.80 1.62

95.44 96.00

1.89 1.75

0.71 1.12

1.39 1.66 1.29

135.76 2.60 41.90

0.93 1.37 2.00

96.00 - -

1.51 1.36 1.56

0.90 0.97 1.51

1.56

2.31

1.36

1.44

0.92

1.63

41.36

1.6a

135.76

1.38

1.43

1.18

41.46

1.60

94.90

1.66

0.60

1.15

95.38

1.42

96.OQ

1.57

1.21

71
Table 10. Mean bone-specific skeletal ages for the 31 individual hand-wrist bones of youths by geographic region, chronological am in years at last birthday, ●nd *x, with atlwtd

standard errors: United States. 1866-1 970–Con.

Trapezium Trapezoid Metacarpal I

North- Mid- North- South westMideast west east South We&

Metacarpal II Standard of reference,

sex, and chronological

age at last birthday North. Mideast west I

South MidW9st West

Male standard

soys:

12 years...........................

13 years...........................

14 years...........................

15 years...........................

16 yea= ...........................

17 yea . ..........................

Girls:

12 years...........................

13 years...........................

14 years...........................

15 years...........................

16 years...........................

17 years...........................

Actual values:

Boys 12-17 years .............

Girls 12-17 years .............

Expected values:

SOYS12-17 years .............

Girls 12.17 years .............

Female equivalent

Girls:

12 years...........................

13 years...........................

14 years...........................

15 years...........................

16 years ..........................

17 years...........................

Male standard

Boys:

12 years...........................

17 years...........................

Girls:

12 yea. ..........................

17 years...........................

Boys 12-17 years ..................

Girls 12-17 years...................

Mean skeletal ags in months

138.4 138.4 139.1

156.0 153.2 155.s

166.8 166.1 16s.7

172.9 173.9 176.3

137.5 13s.4

155.1 153.0

166.6 165.6

172.5 174.1

17s.0 173.s

192.0 185.3

166.7 166.4

174.5 174.5

180.0 179.4

191.5 1s4.4

192.0 189.2

192.0 -

155.6 155.5

171.9 171.7

156.0 156.5

172.0 172.2

134.8 134.7

141.2 141.2

148.0 147.4

160.0 152.4

161.0 157.2

161.0 -

138.4

163.6

168.0

176.7

176.0

161.6

15a.5

176.2

181.1

1s4.7

192.0

192.0

155.6

174.0

155.6

172.6

136.5

143.2

149.1

152.7

161.0

161.0

1.4s

40.s9

1.41

1.90

0.76

13S.6

165.6

16s.3

176.1

17s.1

185.5

165.6

174.s

1S2.3

1ss.5

1s7.s

157.4

171.7

156.4

172.2

134.2

141.4

150.2

156.5

155.6

1.42

41.57

1.66

1.30

1.1s

138.2

154.1

767.6

176.6

175.6

181.6

16S.9

176.4

1s1.1

1S4.4

192.0

192.0

156.1

174.2

15s.9

172.9

136.4

143.4

149.1

152.4

161.0

161.0

1.27

40.99

1.61

1.91

0.s7

136.6

154.4

168.1

177.2

17s.4

1S4.4

171.9

177.6

1s1.0

1S4.2

1S6.0

166.0

15s.9

176.4

15s.1

175.6

140.s

145.6

149.0

153.2

155.0

155.0

137.7

156.1

16s.2

175.7

179.4

184.4

16S.7

176.7

1S1 ,2

1S5.6

164,5

1s5.7

160.3

174,5

?60.6

175.4

136.8

144.7

149.4

154.6

163.5

154,7

139.8

155.0

169.6

176.4

179.4

182.1

172.0

176.4

179.1

1S5.4

1S6.0

1S6.0

161.5

176.1

161.2

175.2

140.0

146.4

147.1

154.4

155.0

155.0

1.SQ

0.S6

1.27

1.03

0.5s

13S.6

155.9

170.4

176.6

177.s

182.6

15s.1

177.2

1S2.6

1S5.4

1S6.0

1S6,0

159.6

175.2

159.2

175.6

137.1

145.2

151.6

164.4

155.0

155.0

1.29

1.26

2.03

66.61

O.sa

0.56

139.6

155,3

170.8

1S3.6

166.7

199.2

173.4

164.7

192.7

197.6

204.7

203.1

164.5

1S4.8

164.0

164.2

141.4

152.7

162.4

167,6

176.7

174.1

1.25

1.72

1.69

2.19

0.81

1,05

136.s

158.1

170.6

180,S

18s.8

196.0

170.0

162.7

194.6

199.2

204,3

204,6

165.2

1S3,8

166.s

1s4.4

13s.0

150.7

1S4.6

168.2

175.3

176.6

1.24

1.35

1.46

3.91

0.s3

0.9s

139.8

154.7

172,2

1s1.3

187.1

192.6

172.4

162.3

195.1

199.1

201.4

204,5

166.2

184.7

166.3

1s4.6

140.4

160,3

165.1

169.1

171.4

176.6

1.s1

1.42

1.06

1.60

0.76

0,s2

136.3

156.0

172.2

1s3,3

1s5.7

196.9

171.7

1S3.8

193.s

199,0

202.1

204.3

16s.0

186.0

164,7

166.0

13%7

161.8

163.8

169,0

172,2

176,3

1.64

2.0s

2.73

2.65

1.31

0,91

177.1 174.0 177.7

192.0 1S5.2 1S5.7

166.6 166.2 165.S

174.4 174.s 174.6

1s0.2 178.7 1S3,2

191.4 177.0 1s8.6

192.0 189.8 187.3

192.0 - -

156,1 155.7 157.5

171.6 171.6 171.6

166.2 156.7 156.6

172.0 172.4 172.2

134.9 134.6 134.4

141.4 141.s 141.6

14S.2 147.4 151.2

160.4 144.0 157.6

161.0 157,s 155.3

161.0 - -

Standard error of the mea”

1.31 1.65

135.76 2.5s

0.99 1.21

96.00 -

1,W 1.39

0.94 0.93

1.40

41.57

1.12

135.76

1.10

96.@3

1.53

1.13

1.50

2.53

1.09

0.91

1.55

93.oa

1.17

1.06

1.26

1.04

1.29

0.28

0.57

0.79

1.54 1.61

1.36

1.13

1.32

0.96

72
Tqble 10. Mean tvme.:paclflc akeletal ages forthe31 individual hand.wrlst bones ofyouths bygeographic region, chronological age Inyears atlastbirthday, andsex, with selected

standard err.ars: Llnited States, 1966-1970-Con.

Standard of reference,

SOX,and chronological

ago at loft birthday

Mdo standard

BOW:

12 years .............................

13 yearn.,.,., ......................

14 years .............................

16 Ware..,,,,..,,,, .................

16 years .............................

17y0ar$ ................$.....!.....4

Girls:

12y08ra .,.,.,,..............,,,.,,,<

13 year:, <.,,,,,.,.,,,.......,..,.,,.

14 years .,.,,,...............,..,,,,,

15yean .............................

16 years ..,,,,.,,, ...................

17 yaam..)..., ..........!......!...i

Actual VdUE!l:

Boys 12.17 years ...............

Girls 12-17 years..,, ............

Expected VdUOt:

Boys 12-17 yaam ...............

Girls 12-17 years................

Famdu oqulvdent

(31rli:

12y0ars.io ..........................

13 years..,,,.., .....................

14 yaart .............................

15yaars ..........!...! ..!...........

16yoar$ .............................

17 years .............................

Male standard

60ys:

12 years .............................

17yesrs .............................

Girls:

12 yenrs.. i.,........................

17 ymrs .............................

Boy] 12.17 yam,,,,,, ...............

Girls 12-17 years .....................

M.9tacarDal 111 I Metacamal IV I Metacamal V I Pkiform

I

North- Mid- South west

North- Mid.

South West North- Mtd- North- Mideast west east west east South west west South east West west

Mean skeletal age in months

140.2

166.9

171.4

1S3.2

187,7

196.0

173.6

1s4,4

191.9

196,2

201,3

201.6

164.2

1B4,3

163.7

163.6

141.6

152.4

160.9

166,2

171.3

171.6

1.28

1.61

1.64

2.39

0,90

1.06

137.6

156.6

171.0

179.7

188.6

196.6

170.6

182.1

192.9

196.7

199.1

199.s

165.1

162.4

165.6

183.3

13S.6

150.1

161.8

166.7

168.1

169.6

1,19

0.s5

1.45

3.52

0.67

0.8S

140.6

165.3

171.6

1s1.1

166.6

191.7

173.6

1S2.6

192.6

196.6

196.3

201.4

166.0

183.9

166.1

163.6

141.6

150.6

161.6

166.6

16S.3

171.4

1.67

1.20

1.15

1.86

0.B3

0.66

139.0

158.6

172.3

183.3

1B5.4

194.5

172.2

182.6

193,0

197.2

201.2

200.0

164.9

164.0

164.6

184.0

140.2

150.6

162.0

167.2

171.2

170.0

1,62

2.36

2,65

1.93

1.01

0.96

140.2

155.8

171.5

163.6

1B6.6

195.7

173.8

1B3.8

181.4

197,2

202.0

201 .s

164.3

164.5

163.7

183.6

141.s

151.s

160.4

167,2

172.0

171.8

1126

1.76

1.56

2.17

0.96

1.11

137.5

156.6

171.1

179.6

1B7.9

195.4

170.2

162.3

192.5

197.6

19s.9

200.1

164.9

182.6

165.5

183.4

13B.2

150,3

162.o

167.6

168.9

170.1

140.0

155.6

171.7

161.5

187.0

190.0

173.0

182.4

192.5

196.2

198.4

200.9

165.8

1B3.6

166.0

183.4

141.0

160.4

162.0

166.2

169.4

170.9

139.0

156.4

172.6

162.7

186.2

193.3

171.5

182.5

193.4

197.3

200.6

200.1

164.7

164.0

164.4

164.0

139.5

150.5

163.4

167.3

170.6

170.1

140.4

156.3

171.6

164.3

180.1

199.2

174.5

185.1

193.2

199.6

203.8

203,8

165.9

166.8

165.2

185.7

142.5

153.1

161.8

168.6

174.6

174.6

138.1

156.9

171.0

160.6

1B8,3

19B.2

170.6

163.0

194.2

199.6

203.2

205.0

166.4

164.5

167.0

185.2

138.8

151.0

162.2

188.B

173.4

176.0

Standard error of the mean

1.36 1.72 1.6B

0.80 1.01 2.32

1.40 1.07 2.84

2.69 1.64 2.12

0.71 0.61 1.02

0.93 0.72 0.96

1.27 1.29

2.06 1.04

1.93 1.38

1.82 2.28

0.83 0.66

1.04 0.62

140.6

155.6

172.3

181.9

188.4

192.B

173.5

1B2.5

194.9

19B.7

201.6

207.0

167.1

186,5

167.3

185,4

141.5

150.5

162.9

166.4

171.6

179.0

1.76

1.36

0.66

1.07

0.66

0.66

139.4

156.6

173.2

162.9

18B.4

194.5

171.6

163.3

194.7

199.2

202.9

204.9

166.0

186.0

165.B

186.1

139.B

151.3

162.7

169.2

172.9

175.9

1.7a

1.62

2.43

1.71

1.01

0.92

142.4 139.9

156.2 157.3

166.5 166.5

174.B 170.5

176.2 177.7

183.4 -

168.6 166.3

175.7 173.8

162.7 181.7

1B3.7 1B7.4

192.0 160.0

192.0 192.0

157.7 157.2

174.5 171.7

167.4 157.7

173.4 172.4

136.6 135.2

142.7 140.9

150.7 149.7

151.7 155.4

160.0 148.0

160.0 160.0

1.14 1.35

4.36 -

1.40 1.11

96.00

1.13 1.04

0.74 1.04

140.7

164.9

167.4

175.7

176.9

185.4

166.5

174.6

179.0

188.6

1s9.1

182.0

15B.5

172.1

158.7

172.9

135.2

141.6

147.0

166.6

157.1

160.0

1.25

4.30

1.39

135.76

0.9B

0.77

141.8

154.B

168.8

176.6

177.0

185.7

167.2

175.2

164.4

1B5.6

184.0

192.0

156,7

173.2

158.2

172.6

135.6

142.2

162.4

153.6

152.0

160.0

2.10

41 .5Q

1.74

74.36

1.02

1.19

73
Table 10. Mean bone-specific skeletal ag+mforth.g31 individual hand.wrist bones of youth$by ~ogmphlc region, chronologiml aWlnyeam atltibltihtiy, sndmx, with wlwtd

standard errors: United States, 1966-1970-Con.

Adducmr sesamoid i Flexor sesamoid I Proximal nhalsmx 1

Standard of reference,

sex, and chronological

age at last birthday

Mfdwest

North-.

east

Mid.

South west

North- Midwest east west South west

-r4unh- M1dMst Wt South I wwt

Male standard

BOYS:

12 yearn.,,,,., ...................

13 years.,.., ......................

14 years ............................

15 years ...........................

16 yen~ ...........................

17 years ...........................

Girlx

12 years ...........................

13 yews ...........................

14 years ...........................

15 years ...........................

16 yearn. ..........................

17 years ...........................

Actual Vahl@S:

BOYS1217 yOWS.............

Girls 12-17 yaws ..............

ExPccted VahlR5:

Boys 12-17 years .............

Girls 12-17 years..............

Female equivalent

Girl*

12 Vows...............,,., ........

13 y80m ...........................

14 years ...........................

15 years ...........................

16 years .........................”

17 years ...........................

Male standard

Boys:

12 years ...........................

17 years........................,..

Girls:

12 years ...........................

17 yearn ..........................

60y5 12-17 years...................

Girls 12-17 years ...................

Meen skeletal age in months

141,3 140.4

1E8.6 166.4

172.3 173.7

1s1.5 183.7

156,6 1s4.4

190.6 196.6

139.3

158.5

170,9

1SO.5

1S7.6

197.4

159.2

165.6

170.1

175.8

177.7

lS1.B

169.6

175.7

177.7

178.9

180.7

178.8

Isa.s

173.6

16s.3

173.6

137.6

143.7

145.7

146.9

148.7

146.S

1.m

70.=

0.89

11,53

0.53

0.3B

159.9

165.3

170.4

173.6

176.7

182.0

16B.9

173.2

1s1.1

177.4

184.0

1B6.9

16S.4

173.3

16S.5

173.8

136.9

141.2

149.1

145.4

162.0

154.9

1.45

96.00

0.90

72.43

0.96

0.86

159.1

164.0

170.0

175.4

174.6

182.1

171,4

175.9

177.5

185.4

1s1.s

187.3

16S.4

175.0

169.0

173.7

139.4

143.9

145.5

153.4

149.s

155.6

0.74

2.76

1.23

59.34

0.45

0.74

160.4

163.8

170.8

175..!

179.C

164.3

169.6

173.4

179.8

130.5

176.3

165.2

169.3

173.4

168.0

173.7

137.5

141.4

147.8

14s.5

146.3

153.2

0.96

2.17

1.34

71.77

0.61

0.80

164.3

171.7

171.7

175.4

177.0

184.7

172.0

176.7

179.4

1SO.5

185.B

167,0

172.2

176.0

171.7

175.9

140.0

144.7

147.4

148.5

153.s

155.0

1,02

92.77

1.07

59.65

0.58

0.85

166.2

lL%C

171.1

174.3

176.6

192,0

170.6

175.9

1s3.0

179.5

1s6.6

186.2

171.1

175.2

171.7

175.6

136.6

143.8

151.0

147.5

153.6

154.2

1.49

135.76

0.B7

72.20

0.92

0.81

154.3

168.5

172.6

175.6

175.6

184.2

173.4

175.1

179.0

164.1

187.0

192.0

172.5

175.s

172.5

175.4

141.4

143.1

147.0

152.1

155.0

161.0

165.9

165.5

172.5

176.S

179.2

186.1

172.7

175.5

179.4

182.0

17s.9

189.6

172.7

175.6

172.4

175.8

140.7

143.5

147.4

150.0

146.9

1=.s

141.3

157.4

172.S

185.9

18S.0

188.5

176.0

186.2

194.9

203.4

207.6

208.5

165.2

1S7.2

164.5

186.3

143.0

154.2

164.9

174.4

179.6

162.5

139.1

158.5

171.8

1BO.9

1BS.S

mo.z

173.6

1S6.1

194.6

202.6

207.2

207.2

165.6

1s5.7

166.1

186.0

140.6

154.1

164.6

173.6

179.2

179.2

141.7

155.8

172.8

1S1.6

1s7.4

193.3

176.4

1s4.5

195.3

ml.7

204.2

205.3

166.1

1S5.6

166.B

185.3

143.4

152.5

165.3

172.7

176.4

177.3

2.01

1.29

1.12

1.55

0.96

Om

140.7

166,0

173.3

163.8

188.1

20Q.2

174.2

162.5

197.4

204.B

205.7

ms.5

165.9

165.1

165.3

185.6

141,2

150.5

167.4

176.6

177.7

1s1.0

141.8

1!%1

172.3

184.s

1B7.B

188.4

176.5

165.2

193,2

18B.9

2C4.O

2C4.O

164.6

1S6.6

163,9

184.5

143.6

152.4

163.1

168.9

174.0

174.0

174.2 175.7 174.3

1S3.6 184.1 182.7

191.3 193.4 104.6

188.9 196.1 200.2

200.5 201.1 2W,7

m2.6 -232.0 204.0

165,4 166,0 164.6

184.2 183.9 183.6

141.2 I 142.7 I 141.3

160.8 161.1 160,4

1W.6 163.2 163.6

168.9 16s.1 170,2

170.6 171.1 170.7

172.6 172.0 174,0

Standard error of the mean

0.78

3.22

1.54

2.s1

1.62 1.11

2.05 2.19

2.55 1.28

1.11 -

1.16 0.86

1.12 1.28

1.56 1.67 1.38

1.66 1.91 2.09

1.07

2.36

1.35

3.s3

1.23

3.13

0.88

1.04

0.69

135.76

1.35

73.W

1.72

0.82

1.11 2.IW

R 1.49 -

0,86 1.04 0.97

1.17 0,46 0,90

0.52

0.6s

1.05

0.69

0.61

1.56

74
Table 10, Mem bone.meclfic skeletal sues for the 31 Individual hand-wrist bones of vouths bv aeow.mhlc reoion, chronological age in vears at last birthdav, and sex, with selected

Standard of reference,

sex, and chronological

ago at last birthday

s

Proximal phalanx III

lard errors: Un;ted Stat&,-19%1970 -~on~

Proximal phalanx IV IProximal phalanx V I Middle phalanx II

EEEE Northeast

North- Mid- South West North- Mideast west east west South I

West

I

North- Mid- 1South east west I

West

Male standard

BOYS:

12 years.,...,, ........................

13 years...............................

t4 years., .............................

15yeam.,..,, .........................

16 vefl~ ..............................

17 veals ...............................

Girls:

12 Veal ...............................

13 veals ...............................

14 years...............................

15ve8r\ ...............................

16 years., .............................

17vears ...............................

Actual Vahlf!s:

BOW 12.17 veam .................

Girls 1217 vears .................

Expected values:

BOVS12.17 years .................

Girls 1247 years .................

Female equivalent

Girl$:

12 years...,.,,,,,, ...............<....

13 years., .............................

14 veals.,..,., ........................

15ymws.,,, ...........................

16 veals ...............................

17vears.,,, ...........................

Male standard

BOW:

t2 years, ..............................

17 veamr.,,.., ........................

Girls:

12 vets ...............................

17 veals.., ............................

SoVs 12.17 years ......................

Girls 12.17 veals .......................

Mean skeletal age in months

141.9

158.2

172.3

185.1

186.8

197.9

176.8

184.7

193.6

199.4

204.0

204.0

164.6

166.0

164.0

1S5.2

144.9

152,7

163.6

169.6

176.0

176.0

1.11

2.8s

1.60

0.96

1.12

139.6

156.6

171.3

181.1

167.7

197.0

174,6

183.6

192.3

199.1

201.5

202.4

165.1

183.9

165.7

1S4.6

143.6

151.6

162.3

169.1

172.5

173.4

1.61

1,41

1.05

3.10

0.s4

107

141.3

157.0

172.6

161.5

186.0

191.3

176.0

184.2

194.5

19s.9

201.0

204.0

165.6

185.0

166.2

184.5

144.5

152.2

t 84.5

168.9

172.0

176.0

1.65

1.84

1.10

0.99

0.46

140.6

166.8

t 73.4

183.6

166.1

197.4

174.3

1s3.4

194.1

200.4

203.0

204.0

165.4

183.6

164.8

184.2

143.3

151.4

164.1

171.4

174.0

176.0

141.6

158.3

172.4

185.1

167.4

197.5

177.4

185.5

193.4

199.5

204.0

203.7

164.6

186.5

163,S

185.4

145.4

153.5

163.4

170.0

176.0

t 75.4

139.3

158.6

171.2

160.9

167.5

19s.0

176.0

163.6

192.3

198.6

201.7

202.6

164.8

184.2

165.4

164.9

144.0

151 .s

162.3

168.6

172.7

173.8

1.63

2.37

1.07

1.64

0.67

0.93

141.6

156.9

172.9

161.1

166.2

180.7

176.5

184.8

194.2

198.6

201.3

201.7

165.5

1S5.2

165.0

164.6

144.s

152.S

164.2

166.s

172.3

172.7

140.4

158.3

173.9

1S4.0

167.3

195.4

174.6

183.4

194.1

200.1

203.2

204.0

165.3

1s3.s

164.7

184.4

143.5

151.4

164.1

171.1

174.4

176.0

142.0

158.2

172.4

185.3

187.5

196.5

177.5

t 65.5

193.3

196.8

204.0

204.0

164.6

186.4

163.S

1S5.4

145.5

153.5

162.3

166.6

174.0

174.0

139.6

158.7

171.3

161.2

187.5

198.6

175.1

184.6

191.6

196.9

200.9

202.7

166.0

1S4.2

165.5

184.8

143.1

162.6

160.6

168.6

171.s

173.4

141.8

157.1

172.4

180.8

186.4

190.7

176.6

184.2

194.0

201.5

201.4

m4.o

165.3

18S.3

165.9

184.S

144,6

152.2

163.0

172.5

172.4

174.0

1.71

2.03

1.04

1.01

0.53

140.6

153.2

173.4

1636

165.9

195.9

174.7

1S2.9

194.8

201.0

203.0

204.0

165.0

184.0

164.7

184.6

142.7

150.9

163.8

172.0

173.5

174.0

142.6

158.6

172.1

182.6

186.6

196.6

177.0

185.3

193.4

188.7

203.6

204.0

164.5

165.9

163.9

184.s

145.0

153.3

163.4

168.4

174.5

175.0

140.1

158.5

171.3

160.1

188.2

197.0

174.3

1S4.7

191.4

199.6

201.0

201.3

165.3

163.0

165.9

1S3.6

142,3

152.7

160.4

170.4

171.0

171.3

141.9

156.4

172.3

161.9

185.6

191.3

176.2

184.4

192.9

199.2

201.3

ml.3

165.6

164.8

186.4

184.5

144,2

152.4

162.6

170.1

171.3

171.3

142.1

.158.3

173.6

183.3

167.6

195.6

174.2

182.7

193.0

200.0

203.1

204.0

165.S

1S2.9

166.0

183.7

142.2

1EQ.7

183.0

170.5

174.1

175.0

Standard error of the mea”

1.24 1.11

2.52 2.S6

2.59 1.18

0.25

1.14 1.02

0.79 t .08

1.74 1.35

1.91 1.96

1.16 2.60

1.71 ‘-

0.94 1.16

0.47 0.93

1.40

2.08

1.26

1.S6

1.36 1.81 1.17

2.35 1.0s 1.64

1.07 1.39 2.54

2.61 1.91 .

1.17 1.01 1.06

0.73 0.55 1.37

1.20

2.95

1.14

0.92

1.2s

1.54

1.80

1.21

1.95

0.66

1.1s

2.47 1.05

1.29

1.05

0.77

1.21

75
Table 10. Mean bone-specific skeletal ages forthe31 individual handwrist bones ofyouths bygeqraphic region, chronol~ical awin yeamat Iratbirthdav,an dsex.withadaetsd

w

Middle pha[mx Ill

dard errors: United States, 1966-1970 –Con.

Middle phalanx IV I Middle ianx V

z

South West

Distal nhalmx I

Standard of reference,

sex, and chronological

age at last birthday

Male standard

Boys:

12 years............. ... ............

13 years..............................

14 years..............................

15 years., ............................

16 years..............................

17years..............................

Girls:

12 years...............................

13 years...............................

14 years...............................

15 years., .............................

16 years...............................

17 years...............................

Actual values:

Boys 12-17 year. ................

Girls 12-17 years ................

Expected values:

Boys 12.17 years .................

Girls 12-17 years ................

Female equivalent

Girls:

12 years...............................

13 years...............................

14 years...............................

15 years...............................

16 years...............................

17 years...............................

Male standard

Boys:

12 years...............................

17 years...............................

Girls:

12 years...............................

17 years...............................

Boys 12.17 yews ......................

Girls 12-17years.......................

T

Nonh- Mid.

east west 1

Mid.

Wst South

*

North

east

141.7

15s.3

172.3

163.2

187.6

I 97.8

176.S

1S6.3

193.8

18B.6

203.4

204.0

164.B

1B6.7

164.1

1S5.4

144.8

154.3

162.8

169.2

174.4

175.0

North watt

141.0

155.7

16a.4

177.6

161.4

16B.B

171.8

1El .0

183.8

1B9.2

189.4

1B9.9

169.7

179.6

159.0

178,5

139.B

149.0

151.4

156,4

158.8

158.6

Mean skeletal age in months

142.4

158.8

172.4

1B3.8

187.0

187.B

177.0

1B5.8

194.0

196.4

203.4

204.0

165.2

166.6

164.6

185.4

145.0

153.B

163.0

168.8

174.4

175.0

1.27

1.63

1.03

—

0.68

1.26

140.2

158.5

171.4

lBO.O

18B.O

197.3

174.5

184.5

191.6

198.5

199.7

201.3

165.5

1B3.3

166.2

1S4.O

141.6

152.5

160.6

170.5

170.7

172.3

141.7

156.6

172.6

162.2

186.4

182.1

176.5

1B4.B

193.8

196.9

201.3

201.6

166.3

1S5.4

166.9

164.9

144.5

152.6

162.8

169.8

172.3

172.6

142.1

158.4

173.5

184,2

167.4

185.5

174.4

183.1

194.1

199.2

202.9

204.0

166.2

1B3.3

165.4

184.0

141.4

151.1

163.1

170.2

173.9

175.0

139.7

15a.o

171.4

180.0

187.9

196.6

174.2

1B4.O

191.8

199.2

201.4

201.7

165.2

163.2

165.8

164,0

141.2

152.0

160.9

170.2

172.4

172.7

1.36

2.14

1.14

1.97

0.95

0.76

141.5

156.0

172.2

182.0

1S5.6

192.1

176.1

184.B

193.2

188.6

201.1

201.3

166.6

165.0

166.4

184.7

144.1

152.B

162.2

169.2

172.1

172.3

141.0

158.1

173.5

163.9

166.9

195.0

174.2

183.5

193.B

199.0

202.8

204.0

165.6

183.4

165.o

184.1

141.2

151.5

162.8

170.0

173.9

175.0

142.1

158.5

172.3

183.1

1S7.O

197.3

176.B

185.4

192.2

198.5

203.1

204.0

164.5

185,B

163.B

184.8

144.8

153.4

161.4

168.5

173.1

174.0

139.B

15B.O

171,2

180.1

187.5

187.0

174.0

IB4.8

190.9

199.1

201.2

201.7

165.1

182.6

165.B

183.4

142.0

152.6

158.9

169.1

171.2

171.7

141.B

155.9

172.0

181.6

185.7

180.2

175.7

1B4.5

193.2

198.1

200.7

201.3

165.6

184.5

166.4

184.2

143.7

152.5

163.2

168.1

170.7

171.3

141.4

158.3

173.3

164.3

167.9

194.9

176.0

181.7

194.2

198.8

203.2

204.0

165.6

182.7

164.9

183.2

143.0

148.7

154.2

168.8

173.2

174.0

138.4

156.6

166.8

173.8

179.2

186.6

170,5

177.5

lB1.6

191.0

188.0

1B6.O

158.8

176.1

159.6

176.6

136.5

145.5

149.5

161.0

157.0

153.0

140.7

154,2

168.5

175.7

177.6

1B4.6

171.2

178.7

1B3.4

1B6.8

187.2

1B6.O

159.3

177,1

169.6

177,1

139.2

146.7

161.2

167.8

154.6

153.0

1.66

2.49

1.29

0.77

0.6B

139.6

156.6

169.8

176.7

179.8

186.8

170.1

176.4

184.8

191.0

191.0

186.0

160.1

176.9

169.6

176,6

138.1

144,4

161.9

161.0

161.0

163.0

1.49

2.02

2,24

41,69

0.97

1,09

Standard errorof the mean

1.43

2.06

1.78

1.02

1.13 1.23

1.34 1.86

2,41 1.18

. -

1.12 0.71

1.42 1.28

1.42

1.70

1.21

1.95

1.40 1.5a

2.04 0.94

1.19 1.51

1.97 1.91

1.02 0.97

0.85 0.51

1.32 1.23 1.33

1.50 2.36 2.51

2.50 1.55 1.20

2.44 -

1.16 0.83 0.97

1.50 0.77 0.86

1.75

0.94

1.37

1.91

1.01

0.50 I

1.05 1.27

2.61 1.69

1.08 1.10

0.71 0.47,

2.47

1.19

1.44

1.21

O.BO

1.20

76
Table 10. Moan bcme-speclflc skeletal ages forthe31 individual hand++rist bcmesof youths bygeographic region, chronological age in yeamat Iastbirthday, andsex, with selwted

standard errors: United States, 1966-1970-Con.

Distal phalanx III Distal phalmx 1I

I Oistal phalanx IV I Distal% halanx V

Standard of reference,

sex, and chronological

age st last birthday

Male standard

Mi&-

West

UmtheastMid- South I

NorthWest west eastNonh- Mideast south West west

Mean skeletal age in months

Boys:

12 YearI ...............................

13 years...............................

14 years ..............................

16 years...............................

16 years...............................

17 yenrt ...............................

138.6

156.8

167.1

173.5

178.3

184.3

169.9

175.5

160.4

185.7

186.0

165.7

159.0

174.3

159.8

174.9

137.9

142.6

146.4

153.7

154.0

153.7

1.33

1.41

1.18

0.45

0.74

0.s3

140.8

155.0

169.7

174.3

176.9

180.8

171.0

176.8

179.8

185.S

186.0

186.0

159.8

175.5

159.9

175.4

139.0

143.8

147.6

153.8

t 54.0

154.0

140.0

166.6

169.2

176.1

179.0

183.4

169.2

176.3

162.0

1S5.8

186.0

186.0

159.6

174.2

159.2

174.8

137.2

143.3

150.0

153.8

154.0

154.0

140.4

154.8

169.1

175.3

177.3

184.5

171.5

179.2

183.7

18s.6

187.5

186.0

159.9

177.4

160.3

177.2

139.5

146.4

151.7

156.6

155.5

154.C

140.1

156.7

169.5

176.8

179.8

787.2

170.0

176.8

185.2

190,9

191.0

166.0

160.4

176.0

159.6

176.8

136.0

144.6

153.2

160.7

161.0

164.0

141.2

156.4

168.9

177.6

181.1

165.7

172.3

181.3

1S4.2

189.3

169.E

190.C

160.2

179.6

159.:

178.1

140.?

149.2

152.1

158.:

158.!

159.(

136.4

156.1

167.1

173.6

178.6

186.0

169.8

176.7

181.5

191.0

188.5

166.0

156.9

175.6

159.9

176.6

137.6

144.7

149.5

161.0

157.0

153.0

1.28

2.36

1.07

0.73

0.99

140.4

154.9

169.2

175.0

176.4

184.3

171.3

179.0

183.5

188.7

187.5

186.0

159.7

177.2

160.0

176.9

139.3

147.0

151.5

157.4

155.5

153.0

140.0

156.7

169.2

176.4

178.S

187.0

169.6

176.8

185.1

190.9

191.0

186.0

160.1

175.8

159.6

176.6

137.6

144.8

152.6

150.8

161.0

153.0

141.6

156.0

169.0

176.2

178.7

163.9

172.0

177.6

181.7

185.7

186.0

186.0

159.3

177.1

158.7

176.0

140.0

145.6

149.7

152.8

152.0

153.0

138.8

156.8

167.6

173.8

178.1

184.3

169.9

175.5

160.1

185.&

166.C

165,E

159.2

174.2

159.s

174.5

137.:

143.!

146.1

152.<

153.(

152.$

140.7

155.1

169.7

174.2

176.9

181.1

170.9

176.9

179.6

185.8

186.0

186.0

159.7

175.4

159.9

175.2

138.9

144.9

147.6

152.9

153.0

153.0

1.46

0.91

1.36

—

0.66

0.69

140.2

156.6

169.0

176.3

177.8

184.1

169.3

176.2

161.9

185.8

166.0

186.0

158.4

174.1

159.0

174.6

137.3

144.2

149.9

152.9

153.0

153.0

1.38

1.02

1.73

—

1.10

1.27

141.6

156.1

158.6

176.4

178.5

183.7

172.2

176.2

181.8

185.6

166.0

166.0

159.4

177.3

158.7

176.0

139.6

145.2

149.6

153.6

154.0

15+?.0

1.03

1.43

1.62

—

0.98

0.79

141.1

156.6

166.9

177.9

181.2

165.8

172.4

181.6

184.4

189.3

169.3

190.2

160.2

179.8

159.3

176.4

140.4

149.6

152.4

157.3

157.3

158.6

138.5

158.8

167.6

173.6

178.4

186.2

170.3

177.6

161,8

191,0

188.2

166.0

159.0

176.1

169.9

176.9

138.3

145.3

149.6

161.0

166.2

154.0

Girls:

12 years..............................

13 years. ..............................

14 yeer5,.............................

16 years..............................

16 years..............................

17 yearn ..............................

Actual Vdlle$:

BOYS12-17 Wars. . ..............

Girls 12.17 years ................

Expacted VOhlES:

80Y$ 12.17 veals ................

Girls 12.17 years ................

Femaln equivalent

Glrk:

12 year: ..............................

13 years..............................

14 yem’s..............................

16 yam. .............................

16 years .............................

17 years..............................

Male ttendard Standard error of the mean

1

1.00 1.38

1.32 1.60

1.49 1.18

— 0.60

0.96 0.83

0.78 0.90

80VS:

12 years...............................

17years ...............................

1

.1.47 1.10

1.62 3.53

2.01 1.83

2.46

1.11 1.01

0.96 0.73 1- 1.49 1.45

1.04 1.13

1.29 1.70

0.62 1.18

0.66 1.28

1.09.1.26 1.46

2.85 2.28 1.45

1.82 1.08 1.32

2.60 – -

1.42

1.66

1.44

1.63

1.20

0.62

0.72

—

Girls:

12 years...............................

17vears ...............................

1.65

1.04 &lE-k 0.91

80Y1 12.17 years ......................

Glrh 12.17 years.......................

77
Table 11. Mean bOne-specific skeletal ages forselected hand.wristb0nesof youths byannual family income, chronological ageatlast titihday, andsex, with selected standard

errors: United States, 1966-1970

I

Metacarpal III IMetacarpal V I F’roxirnalphalanx lll

Standard of reference,

sex, and chronological

age at last birthday

Male standard’

Boys:

12 years .....~...........................~ .......

13 years ..........................................

14 years ..........................................

15years ..........................................

16 years ..........................................

17 years ..........................................

Girls

12years ...........................................

13 years ...........................................

14 years ...........................................

15 years ...........................................

16 years ...........................................

17 years ...........................................

Actual values:

BOYS 12-17 years .............................

Girls 12-17 years .............................

Expected values:

Boys 12-17 years .............................

Girls 12-17 years .............................

Female equivalent

Girls:

12 years..., .......................................

13 ye.9rs,,.........................................

14 years,., ........................................

16 years ...........................................

16 years.,, ........................................

17 years ...... .....................................

Male standard

Boys 12-17 years ..................................

Girls 12-17 years ...................................

Less

than

$5,00(

140.0

153.1

167.8

172.7

176.2

185.2

165.7

174.6

1S0.6

190.0

171.0

156.7

171.4

157.7

172.6

134.8

141.6

14S.6

160.0

13s.0

$5,000-

$9,999

138.1

158.7

188.6

174.5

175.6

186.3

166.3

174.2

180.0

189.2

185.0

192.0

158.3

171.8

156.5

172.7

135.3

141.2

148.0

157.6

153.0

162.0

$10,000

or

more

4

142.0

154.2

167.4

176.1

1s0.2

188.1

170.0

175.6

185.8

182.8

189.6

191.1

157.6

174.8

157.1

172.6

137.0

142.6

153.8

150.8

158.8

161.1

I

Less

than

$5,00[

138.4

154.8

171.8

180.0

185.B

193.0

172.8

1s2.2

192.9

19s.0

200.8

199.3

165.1

183.5

166.1

183.4

140.9

150.2

161.9

16S.0

170.8

169.3

$5000- $10,000 Less $10,000 Less

$9;999 ‘r ~:h:~ Y9;Y9: ~:re

more , $?%0 ~~

Mean skeletal age in months

137.2

157.5

171.9

161.7

187.2

194.5

171.4

183.0

190.6

186.6

200.1

202.2

164.6

183.2

164.6

183.8

139.4

151.0

159.6

166.6

170.1

172,2

140.8

155.4

171.3

182.8

189.0

187.1

173.0

182.4

184.6

188.2

199.0

198.4

165.1

183.8

164.5

183.4

141.0

150.4

163.6

166.2

169.1

168.4

138.5

165.2

172.6

1S0.6

187.4

193.B

173.5

1S2.5

194.7

200.9

204.5

203.0

166.2

185.3

167.2

1B5.O

141.5

150.5

163.4

170.9

175.5

173.0

137.7

158.0

171.8

181.8

189.2

196.7

171.4

183.8

192.3

198.4

202.6

208.1

166.0

185.1

166.1

185.8

139.4

151.8

161.2

167.8

172.6

177.1

Standard error of the mean .

141.2

155.6

171.6

1B3.7

180.4

197.4

172.7

183.1

196.1

199.8

202.4

203.6

156.1

186.1

165.6

185.7

140.7

151.1

165.1

168.8

172.4

173.6

0.82

0.73

138.1

158.9

172.6

180.7

1S6.1

193.5

176.1

183.3

193.4

201.0

202.6

284.0

164.9

164.6

166.1

184.6

144.6

151.3

163.4

172.0

173.6

176.0

139.8

159.5

172.1

181.9

187.5

195.8

174.4

184.0

190.9

188,3

203.6

204.0

164,8

183.9

164.7

184.7

143.4

152.0

180.8

169.6

175.2

176.0

1.21

II

0.53

0.68 0.57

$10,000

or

more

142.0

157.9

172.5

184.5

188.1

200.3

175.9

164.0

195.8

198.9

201.8

202.1

165.5

165.5

164,S

165.0

144.4

152.0

165.8

168.9

172.8

173.1

0.62

0.73

78
Tabla 11, Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last birthday, and sex, with selected standard

Standard of reference,

sex, and chronological

age at last birthday

Male stendard

Boyc

12v0ars.,.., ......................................

13 yaars ....l...,,,, ...............................

14 years, .....................................

15years ...........................................

16 year . .....................................

17yeers ...........................................

Girls:

12yeers,..i..,o,, ............o....................

13 year,...,,.,..,... !,..,., .................

14 years ........i ..................................

16ynars ..................................... ......

16 yaers ...........................................

17years ...........................................

Actual values:

BOYS 12.17 years .............................

Girls 12.17 years .............................

Expectad VdURS:

Boys 12.17 years .............................

Girls 12.17 yeers .............................

Female equivalent

Girls:

12y0ars ...........................................

13 yeers,,.o,.,.., .............l ...................

14 yaars .......................o...................

16 years ...........................................

16 veals,., ...................................

17 years,..,,, .....................................

Male stenderd

Boys 12-17 years ,,,,,.,,,,.,,.,...,.,..,..,.,,,..,

Girls 12-17 years.,,.,, .............................

errors: United States, 1966-1 970-Con.

Proximal phalanx IV 1Middle phalanx V I

Radius I

Ulna

139.2

156.8

172.5

180.9

1s5.3

193.1

176.6

1S4.O

193.2

201.0

202.6

201.5

164.6

185.1

165.6

1S4.8

144.8

152.0

163.2

172.0

173.6

172.5

1.22

0.68

139.5

159.4

172.4

1S2.O

168.5

195.2

174.5

1s4.2

191.0

198.8

203.6

204.0

184.8

184.1

164.6

184.8

143.5

152.2

161.0

168.8

175.2

176.0

141.8

157.4

173.0

1s4.2

167.3

200.0

176.6

1SS.6

194.8

198.7

201.8

202.5

165.2

185.6

164.5

185.3

144.8

151.6

164.S

168.7

172.8

173.5

140.6

156.8

172.1

179.9

186.5

191.9

175.9

183.4

192.1

198.2

201.6

202.5

164.S

183.8

166.1

183.9

143.9

151.4

161.2

168.2

171.6

172.5

$5000- $10,000 Less $10,000 Less $10,000

$J,999 0’

$17ano ~&&~ or

more , more

~:;;. ~@j or

more

140.0

159.2

172.2

162,2

187.4

185.9

174.2

183.8

192.1

199.4

202.6

204.0

166.2

183.7

165.0

184.2

142.2

151.8

161.2

169.4

172.6

174.0

Mean skeletal age in months

142.3

157.4

171.7

182.7

187.6

198.4

176.1

184.0

192.9

t98.1

202.0

202.7

164.9

180.4

164.5

184.0

144.1

152.0

162.6

168.1

172.0

172.7

138.9

156.0

173.8

186.0

196.1

204.9

175.4

1S4.4

197.2

208.6

214.7

216.3

174.6

196.6

175.7

196.6

143.4

152.4

167.2

182.2

191.4

193.3

138.8

158.6

174.1

1S6.1

196.2

207.2

173.0

1S6.2

196.9

208.7

214.1

218.2

174.8

197.0

174.8

197.1

141.0

154.2

166.9

182.4

190.2

195.2

Standard error of the mean

0.53

0.57 I :21 :::1 :::

140.5

155.9

172.2

1SS.2

200.2

20S.7

173.2

185.7

199.6

208.0

214.8

215.9

175.6

199.2

175.0

199.2

143.2

153.7

169.6

181.0

191.6

192.9

. . .

. . .

139.5

166.0

173.5

183.7

194.0

200.5

174.8

184.5

195.5

203.5

206.9

205.8

172.5

190.4

173.2

190.6

142.8

152.5

165.5

174.0

179.9

178.6

. .

138.5

158.0

173.8

185.7

193.4

202.5

172.4

185.6

195.0

204.2

205.3

209.4

172.0

190.7

171.9

191.1

140.4

153.6

165.0

175.4

177.6

1S2.4

. . .

. . .

140.7

155.3

171.7

187.7

196.6

202.9

172.9

185.1

199.1

203.1

206.7

208.5

172.3

193.0

172.0

192.6

140.9

153.1

170.1

173.2

179.7

181.5

. . .

. . .

79
Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths by annual family incom

errors: United States, 1966-1 970–Ccm

Capitate

!

Hamate

Standard of reference. t , 1 r

sex, and chronological Less $10,000 Less $10,000

age at last birthday

~j’~o %:9: more ‘r &hym %,:E ‘r

, more

chronological age at last birthday, and sax, with seloctod standard

Lunate

!

Smphoid

1 I 1

Less $10,000 Lass $10,000

~;:m %%- ~;re &o %% 0’ more

Male standard Mean skeletal age in months

Boy%

12years ...........................................

13 veals ......................................

14 iears ...........................................

15years ...........................................

16yeam ...........................................

17 years ...........................................

Girls:

12years ...........................................

13 years..., .......................................

14years ...........................................

15years ...........................................

16 years ...........................................

17vears ...........................................

Actual VdUeS:

BOYS 12-17 years .............................

Girls 12-17 yeara .............................

Expectad val uex

Boys 12-17 years .............................

Girls 12-17 years .............................

Female equivalent

Male standard

Boys 12-17 yeara ..................................

Girls 12-17 years ...................................

139.9

153.7

16B.2

173.0

176.3

1B3.B

166.8

175.7

180.7

190.0

179.0

192.0

157.1

172.7

158.2

173.5

135.4

143.7

14B.7

159.0

147.0

162.0

. . .

. . .

139.1

157.5

156.8

174.9

176.1

185.9

167.1

175.2

180.2

188.4

184.0

192.0

156.7

172.5

156.9

173.4

135.2

143.2

14B.2

157.4

152.0

162.0

...

... I

142.7

155.1

168.1

176.1

179.6

1B7.6

169.9

176.3

1S6.0

164.3

190.3

191.3

15B,3

175.1

157.6

173.4

137.9

144.3

154.0

152.3

159.6

161.3

141.4

154.6

168.7

173.5

177.7

164.7

168.0

175.8

181.4

190.0

171.0

192.0

157,8

173.1

158,B

173.9

136.0

143.8

149.4

159.0

139.0

162.0

... ...

... ...

140.7

15B.4

167.9

175,6

177.1

186.2

167.6

175.9

180.2

189.7

184.0

192.0

157.7

172.9

157.6

174.0

135.6

143.9

146.2

158.7

152.0

162.0

143.1

155.5

167.9

176.B

180.4

187.9

171.5

177.2

183.0

183.8

190.3

131.3

158.3

176,1

158.1

174.2

139.5

145.2

151.0

151.8

159.6

161.3

139.9

154.1

167.4

172.3

176.0

1B5.1

166,0

175.0

179.8

190.0

192.0

158.8

171.6

157.7

172.3

135.0

142.0

147.6

159.0

161.0

13B.7

156.2

167.0

173.9

175.6

185.5

166.0

174.0

179.4

189.1

164.0

192.0

155.9

171.4

156,3

172.6

135.0

141.0

147.4

15B.1

152.0

161.0

142.1

154.7

187.6

176.1

179.7

186.2

169.6

175.6

185.7

163.1

188.7

190.2

157.8

174.8

157.1

172.9

137.6

142.6

153.7

151.1

157.7

159.2

Standard errm of the mean

138,4

153.1

187.2

172.7

176.6

182.7

165.7

174.7

179.3

190.0

190.6

166.0

171.6

157.0

172.1

733.8

142.7

147.3

159.0

159.6

137.6

155.4

166,6

174.7

175,6

1B6.3

165.1

173.8

179.6

168.6

184,0

192.0

155.4

171.0

155.6

172,2

133.6

141.B

147.6

157.6

152.0

161.0

:::1 :::1

140.2

154,0

167,3

176.9

179.4

190.5

169.4

175.6

186.3

182.1

1BB,9

169.9

167.1

174.9

166.6

172.7

137.B

143.6

163.3

160.1

157.9

166.8

. . .

. . .

80
Table 11. Mean bona-specific skeletal ages for selected hand-wrist bones of youths by annual family income, chronological age at last birthday, and sex, with aalacted standard

errors: United States, 1966-1 970 —COn.

Standard of referenca,

sax, and chronological

age at last birthday

Male standard

BOYS:

12years ....................................i ......

13 years ...........................................

14 years ......................................

16 year . .....................................

16 YellrS..., .......................................

17years ...........................................

Girl&

12 years ...........................................

13 years, ........i .................................

14 years ...........................................

16 years.., ........................................

16 years ...........................................

17 years ......................................

Actual values:

Boys 12.17 years .............................

Girls 12-17 years .............................

Expgcted values:

BOYS 12.17 years .............................

Girls 12-17 years .............................

Female equivalent

Girls:

12years.. i........................................

13 ymrs ........i ..................................

14 years<..........................................

16 years ...........................................

16 years.., ........................................

17 years ...........................................

Male standard

Boys 12.17 years ..................................

Girls 12-17 years., .................................

137.7

152.2

167.5

172.4

176.4

183.5

165.5

174.4

1s0.1

191.0

191.3

155.7

171.5

158.8

172.3

134.2

141.2

148.1

159.0

159.6

...

...

$5,000.

$9,999

TraDezium I Trapezoid

!

Metacarpal I

Less

than

$5,000

136.6

155.7

166.2

174.5

175.8

186.1

164.8

174.7

179.2

189.1

185.0

192.0

155.0

171.2

155.3

172.4

133.9

141.4

147.2

157.1

153.0

161.0

,,,

. . .

I

$10,000 Less

or than

more $5,000

139.7

154.2

167.5

175.9

179.8

189.2

169.3

175,5

185.8

164.0

189.1

192.0

156.9

174.8

156.1

172.7

137.3

141.8

153.8

152.0

157.1

161.0

138.0

152.4

167.7

172,2

176.6

183.4

165.4

174.9

181.3

191.0

191.3

155.7

171.9

157.0

172.5

134.2

141.9

149.3

160.0

160.3

:::1 :::

$5,000- $10,000 Less $10,000

$9,999 ‘r more

$$:;O :~9-

more

or

I

Mean skeletal aga in months

137.2

155.6

166.5

174.7

175.5

187.0

165.2

174.4

179.1

189.1

185.0

192.0

155.4

171.2

155.6

172.4

134.1

141.4

146.2

157.1

153.0

161.0

140.2

154.3

167.7

176.0

176.9

166.4

169.7

175.5

185.6

162.8

189.2

192.0

157.0

174.8

156.4

172.6

136.6

142.5

153.6

150.8

167.2

161.0

13B.O

153.9

169.4

174.7

178.8

183.0

170.2

177.5

179.9

186.0

186.0

186.0

160.0

175.5

160.8

175,5

138.2

145.5

147.8

155.0

155.0

155.0

137.0

156.7

169.1

176.8

177.9

183.5

169.5

177.1

180.3

185.2

186.0

186.0

159.4

175.2

159.5

175,7

137.5

145.1

14s.3

154.2

165.0

155,0

140.0

154.8

169.4

177.3

180.7

185.7

171.4

177.3

183.1

184.6

184.3

186,7

160.2

175.9

159.8

175.2

139.4

145.3

152.1

153.6

153.3

154.7

Metacarpal II

137.6

154.2

171.3

180.1

187.4

193.2

171.9

182.4

195.5

200.3

205.6

200.9

165.2

1S4,6

186,2

184.4

139.9

150.4

165.5

170.3

176.8

170.9

136.7

157.0

171.9

181.6

187.1

196.5

170.9

183.8

191.3

197.8

202.5

206.7

164.5

184.1

164.6

184.7

138.9

151.8

160.3

167.8

173.0

178.7

Standard error of the mean

. . .

Ill ... ...

... ... ... :::1 :::1 :::1 :::1

140.0

164.6

171.0

164.2

189.6

200.0

172.4

182.7

186.0

189.1

202.8

199.6

165.6

184.7

164.9

184.4

140.4

150.7

168.0

169.1

173.6

169.6

. . .

. . .

81
Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of Youths bv annual family income. chronological age at last birthday. and sex, with sekted standard

errors: United States, 1966.1 970 —Ctm.

I , m

Standard of reference,

sex, and chronological

age at last birthday

Male standard

soys:

12 years ...........................................

13 years ...........................................

14 years ...........................................

15 years ...........................................

16 year...,.., ...............................

17 years ..........................................

Girls

12 years ...........................................

13 years ...........................................

14 years..,.,..,, ..................................

15years ...........................................

16 years ......................................

17 years ...........................................

Actual values:

Soys 12-17 years .............................

Girls 12-17 years .............................

Expected valuas:

BOYS 12-17 years .............................

Girls 12.17 years .............................

Female equivalent

Girls:

12years ...........................................

13 years ...........................................

14 years ...........................................

15 years ...........................................

16 years ...........................................

17 years ...........................................

Male standard

BOYS 12-17 years ..................................

Girls 12-17 years ...................................

Metacarpal IV I Pisiform I Adductor sesamoid I Flexor sesamold

Leas

than

$5,000

138.4

154.7

172.2

179.6

185.7

191.8

172.4

181.7

192.7

198.6

201.2

200.1

164.8

183.6

166.7

183.5

140.4

149.7

162.4

168.6

171.2

170.1

,..

,,.

$5,000- $10,000 Less

$9,999 0’

than

more $5,000

137.2

157.6

171.s

181.7

187.4

193.3

171.0

1s2.s

190.8

196,3

200.0

202.7

164.7

1s3.1

164.6

183.7

139.0

150.8

159.8

166.3

170.0

173.4

140.7

155.3

171.3

182.3

188.5

196,6

172.5

1S2.6

194.3

197.3

199.2

189.3

164.8

1B4.O

164.3

1B3.5

140.5

150.6

164.3

167.3

169.2

169.3

,.. I

.,.

... ...

140.5

153.5

167.8

173.1

178.3

187.2

166.0

174.8

181.2

180.0

192.0

192.0

158,5

172.2

159.3

172.9

135.0

141.s

149.2

148.0

160.0

160.0

$5000- $10,000 I

Less $10,000 Less

W;999 0’ ~:h:o fiT9t ~:re

than

more , $5,000

Mean skeletal age in months

140.5

157.5

167.0

173.7

173.2

1S3,8

166.0

173.9

180.4

189.3

188,4

192.0

157.3

172.3

157.3

173.1

135.0

140.9

148.4

157.3

156.4

160.0

141.0

154,8

167.4

174.7

181.0

190.4

169.3

175.6

184.8

181.9

189.9

192.0

157.4

174.4

157.5

172.6

137.3

142.6

152.8

149.9

157.9

160.0

15s.4

153.9

170.2

173.4

176.1

181.3

170.5

175.2

177.4

181.4

184.3

162.7

16B.2

174.0

169.3

173.6

138.5

143.2

145.4

149.4

152.3

132.7

160.6

165.6

170.5

175.6

178.3

183.9

169.7

173.8

177.5

184.5

184.6

187.0

168.8

173.8

168.5

173.8

137.7

141.8

145.5

152.5

152.6

155.0

159.3

184.B

170.1

174.4

180.8

187.0

169.3

173.5

1B3.2

176.7

175.6

186.9

168.7

173.6

168.6

173.9

137.3

141.5

151.2

144.7

143.6

154.9

162.9

167.9

171.6

174.0

177,3

183.2

174.1

175.6

179.0

183.4

191.4

186.0

171.7

176.4

172.6

175.6

142.1

143.6

147.0

151.4

180.4

154.0

I

$5,00c- $10,000

$9,989 0’ more

165.2

170.0

171.9

175,B

175.8

184.9

172.1

176.3

179,1

1S4.6

184,4

1S8,2

172.1

175.7

171,8

175.9

140.1

143.3

147.1

152.6

152.4

157.2

Standard error of the mean

II ... ...

... ... :::1 :::1 :::1 :::1 :::1 :11

165.6

167.1

172.0

174.9

1BO.6

189,8

170.8

176,0

184,0

177,9

179.2

189.6

172.0

176.3

172.0

175.7

138,8

144.0

152.0

146.9

147.2

158.5

. . .

,..

82
.

Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones (

Standard of reference,

sex and chronological

age at last birthday

Male standard

Boys:

12 years ...........................................

13 years.,,,,.,,.,,.,,.,,.,..,..,..,.,,,.,..,,,...,

14 years,,., .......................................

15 years ...........................................

16 years., .........................................

17 years ...........................................

Girls:

l2years,,,,,.,,,.,.,...,.,..,.....,.,..,..,.....,,

13 year,,.,,..., .............................

14 years,,...,,..., ................................

16years ...........................................

16 yearn ..........................................

17 years ...........................................

Actual values:

Boys 12-17 years .............................

Girls 12-17 vears .............................

Expected values:

60vs 12-17 veals .............................

Girls 1217 years .............................

Female equivalent

Girls:

12 years,,,.,..,,,,,..,,.., ........................

13 years ................i ..........................

14 years ...........................................

l6years,.,,..,.,,,,,,,,,.,...,,.,..,.........,....

16 year.,,.,, ................................

17 years ...........................................

Male standard

Boys 12-17 veara ..................................

Girls 12-17 veara ...................................

errors

Proximal phalanx I

Less

than

$5,000

139.5

155.9

172.4

I 80.4

188.5

195.7

175.7

163.7

194.2

203.1

207.5

204.5

165.7

185.0

166.8

165.5

142.7

151.7

164.2

174.1

179.5

176.0

. . .

. . .

$5,000-

$9,999

139.1

156.6

173.2

162.7

188.1

200.2

173.6

184.7

193.8

203.4

207.0

208.7

165.4

185.5

165.2

166.2

140.6

152.7

163.8

174.4

179.0

181.4

. . .

. . .

$10,000

or

more

142.1

157.1

172.0

164.4

166.2

201.8

175.7

18.5.7

197.B

204.0

204,9

207.6

165.5

187.1

165.0

166.2

142.7

153.7

167.8

175.0

176.8

179.6

. . .

. . .

fouttts bv annual tam!ly income, cnronologlcal age at last mrtrmay, ana sex, wlrn semxed standard

htited States, 1966-1 970–Con.

Proximal phalanx II I

Proximal phalanx V

I

Middle phalanx II

Less

than

$5,000

138.6

156.5

172.4

180.4

186.2

193.3

175.3

162.8

192.6

200.8

202.6

201.8

164.6

183.9

165.9

184.1

142.3

150.4

162.2

170.8

172.6

171.8

. . .

. . .

$5,000- $10,000 Less $5000- $10,0+30 Less

$9,999 ~:re $&o $Q’~” :,.

than

$5,000

I 1 I 1 1

Mean skeletal age in months

139.6

159.3

172.1

182.1

187.9

195.8

174.3

183.7

190.4

198.8

202.4

204.0

164.7

183.4

164.6

164.1

141.3

150.6

158.4

168.6

172.4

174.0

142.0

157.5

172.3

184.2

187.4

200.4

175.9

163.9

195.2

196.5

201.4

202.2

165.2

185.1

164.5

164.5

142.9

150.9

164.2

168.5

171.4

172.2

139.5

158.7

172.8

160.6

165.6

194,1

176.4

183.0

193.1

202.3

202.7

204.0

164.8

184.6

165.9

184.8

144.4

151.0

162.1

173.2

173.4

174.0

139.6

159.5

172.5

181.6

187.9

184.6

174.6

184.3

190.7

199.3

203.6

204.0

164.5

184.3

164.5

184.9

142.8

152.3

158.7

169.3

173.8

174.0

Standard error of the mean

...

... I

:::, .... .

... ...

142.4

157.4

172.1

184.2

186.6

199.9

176.6

184.0

194.4

199.7

202.3

202.7

165.0

185.9

164.4

185.4

144.8

152.0

163.4

169.7

173.2

173.4

140.6

155.8

172.4

178.6

186.3

193.0

176.3

183.8

191.7

199.7

202.6

202.1

165.0

184.2

166.2

184.2

144.3

151.8

160.7

170.4

173.2

173.0

I

$5 ~o. $10,000

$9’,988 ~:re

140.5

159.4

172.1

161.6

167.7

196.2

174.3

183.8

191,6

199.5

203.2

204.0

165.2

183.6

165.1

184.2

142.3

151.8

160.6

170,2

174.2

175.0

:::] :::1 :::

143.0

157.7

172.1

183.4

188.1

198.2

176.1

184.0

193,9

199.6

201.8

202.7

165.3

184.6

164.6

184.3

144.1

152.0

163.9

170.3

171.6

173.4

. . .

. . .

83
Table 11. Mean bone-specific skeletal ages for selected hand-wrist bones of youths bv annual familv income. chronological age at last birthday, and sex, with selscted standard

Standard of reference,

sex, and chronological

8SS at last birthday

Male standard

soys:

12 years ......................................

13 years ...........................................

14 years..., .......................................

15 ye.9rs,., ........................................

16 years ...........................................

17 years ...........................................

Girls:

12 years ..........i ................................

13 years..., .......................................

14 years ...........................................

15 years ...........................................

16 year.s...........................................

17 years... c.........c...c.....c...................

Actual values:

BOYS 12-17 years .............................

Girls 12.17 years .............................

Expected values:

SOYS 12-17 Y13w5.............................

Girls 12-17 years .............................

Female equivalent

Girls:

12 years ...........................................

13 years ...........................................

14 years ...........................................

15 years ...........................................

16 years ...........................................

17 years ...........................................

Male standard

BOYS 12.17 years ..................................

Girls 12-17 years ...................................

errors: United States, 1966-1970-Con.

Middle phalanx Ill

=

140.9

156.0

172.5

1s0.1

1S6.6

193,5

176.5

1S4.O

193.2

199.4

202.1

2U1.9

165.6

1s5.0

166.7

1s4.s

144.5

152.0

162.2

170.4

173.1

172.9

...

.,.

140.5

159.3

172.3

1S2.9

1s7.3

196.S

174.3

183.9

192,0

199,1

201.6

204.0

165.7

1s4.0

165.5

184.s

141.3

151.9

161.0

170.1

172.@

175.0

. .

. . .

142.6

15s.0

172.3

1S2.7

1S8.3

19S.2

176.3

1s4.7

194.2

199.3

201,5

202.7

165.3

165.2

164.9

1S4.5

144,3

152.7

163.2

170.3

172,5

173.7

Middle phalanx IV

Lass

than

$5,00Q

140.1

155.4

172.6

1s0.0

1s6.6

194.0

176.4

184.0

193.1

19s.7

201.9

202,5

165.2

184.s

166.3

1s4.7

144.4

152.0

162.1

169.4

172.9

173.5

Distal ❑halanx [ I Distal c!halanx II

140.0

158.8

172.3

1S2.2

1S6.9

196.1

174.0

1S3.6

190.6

199.1

203.3

204.0

165.2

1S3.8

165.1

1S4.6

141.0

151.B

159.2

170.1

174.3

175,0

Mean skeletal age in months

141.9

157.6

171.s

183.1

188,2

197,6

176.0

1S5.2

191.6

199.1

202.0

202.7

165.0

1s5.4

164.6

1S4.6

144.0

153,2

160.6

170.1

173.0

173.7

139.4

152.9

168.s

173.3

178.4

165.5

170,6

17s.4

1s1.2

191.0

1S6.0

1s9.0

158.6

176.6

159.9

176.9

136.6

146.4

149.2

161.0

153.0

158.0

136.5

157.4

16s.0

175.3

179.8

1S5.2

168.0

177.7

1s2.1

1s9.5

189.8

1S7.6

15s.9

176.4

159.0

177.5

137.0

145.7

l!W.1

159.0

159.6

155.s

140.9

156.1

167.9

177.5

180.7

190.6

173.4

179.1

1s6.6

1%X9

190.9

180.0

159.s

179.2

159.2

177.3

141.4

147.1

153.6

160.9

160.9

148.0

139.0

153.6

168.3

173.5

178.0

165.4

170.2

178.9

1s1.s

191.0

1ss.0

190,2

158.6

176.6

160.1

177.0

136.2

145.9

149.8

161.0

154,0

15S.6

Standard error of the mean

138.7

168.0

168.5

175.6

17s.s

1s5.3

168.2

178.0

1S2.S

1S9,6

1S7.6

187.6

15s,5

176,6

169.5

177.7

137.2

145.6

150.s

167.5

155.6

155.6

...

...

141,3

166.1

166.s

176.9

161.7

190.5

173.6

179.3

186.3

180.9

191.0

1S6.0

160.3

178.3

169,6

177.4

141.6

146.6

164,3

160,7

161.0

154.0

...

...

84
Table ll. Mean bone.speclflc skeletal ages forselected hand.wrlst boneso

wrors:

Standerd of reference,

sex, and chronological

age at last birthday

Mele stenderd

Boys:

12years ...............................................................................................

13 years ...............................................................................................

14 yeers ...............................................................................................

15yeers ..............................c..c...c.o.............................4.........i ...............

16 years ...............................................................................................

17 yeers ...............................................................................................

Girls:

12 yaars ...............................................................................................

13 yeers ..............................c...............................c................................

14 vOers...............................................................................................

16yeers ...........................)...................................................................

16 years ............................................................. .................................

17years ...............................................................................................

Actual When:

BOYS 12-17 yeers .................................................................................

Girls 12-17 yeers .................................................................................

Expacted velues:

60YS 12-17 vears .................................................................................

Girls 12-17 years .................................................................................

Female equivalent

Girls:

12 years ...............................................................................................

13 years ..............................................d................................................

14 years ,..,,.,,..,.. !....... ..........................................................................

15 yeers...l ....i ......................................................................................

16 yeers ...............................................................................................

17yeer: ...............................................................................................

Male stsmderd

BOYS 12.17 years ......................................................................................

Girls 12-17 years .......................................................................................

~ouths by annual family income, chronologiml ageatlest tifih*y, andsex, with sel~ted standard

Inited States, 1966-1970-Con.

Distal III

139.0

153.6

lEa.3

173.4

177.7

165.8

169.7

17S.6

181.8

191.0

1S6.0

190.2

158.5

176.4

159.s

176.S

137.7

146.6

149.8

161.0

153.0

159.4

138.8

157.9

168.4

175,3

178.0

185.0

16s.9

177.6

182.4

189.5

187.6

187.5

159.3

176.2

158.2

177.4

136.9

145.6

150.4

158.5

155.8

155,5

141.2

155.5

168.6

176.4

181.3

190.7

173.4

179,0

186.2

190.8

191.0

186.0

160.2

179.0

159.6

177.0

141.4

147.0

153.4

160.6

161.0

153.0

Distal IV I

Distal V

Less Less ~5mo. $lo,ooa

&:&’. $8’,s99 0’ more

Mean skeletal age in months

139.1

153.6

15s.3

173.2

177.9

161.8

169,2

177.0

179.9

186.0

186.0

166.0

158.5

174.6

159.8

175.1

137.2

145.0

147.9

153.0

153.0

153.0

139.0

158.8

166.6

175.3

176.3

184.4

169.2

175.3

179,8

185.S

186,0

186.0

159.0

174.6

159.0

175.5

137.2

143.3

147.6

162,9

153.0

153.0

141.6

156.0

158.9

176,1

1s1.1

185.8

173.2

177.0

183,2

185.7

166.0

185.6

159.8

176,8

159.1

175.0

141.2

145.0

151.2

152,6

163.0

152.8

139,2

153,3

15s,3

173;0

177.8

181.6

170.0

177.3

179.8

186.0

186.0

186.0

15s.3

174.9

169.8

175.2

136.0

144.3

147.6

154.0

154.0

154.0

138.9

16s.0

16s.5

175.3

177.2

184.5

lm.o

175.3

180.0

185.7

186.0

186.0

159,3

174.5

159.1

175.5

137.0

142.6

14s.0

153.7

154.0

154.0

Standard error of the mean

... ... ... ... ... ... ... ...

... ... .,. ... ..! ,.. . . . . . .

141.4

15s.1

18s.7

176.3

161.0

185.2

173.2

177.4

183.2

1s5.5

186.0

1S5.6

159,8

177.0

159.2

175.1

140.4

144.4

151.2

153.5

154.0

153.6

. . .

.!.

85
Table 12, Selected percentiles in the distribution of the individual youth's range in bone-specific skeletal ages fortheradio-opaque (not

adult) bones in the handwrist for white and Negro youths by chronological age in years at last birthday and sax: Unitad Statas,

1966-1970

Chronological age in years and sex

Boys

12 years ........................................................................................................................

13 years ... . ...................................................................................................................

14 years ........................................................................................................................

15 years ........................................................................................................................

16 years ........................................................................................................................

17 years ........................................................................................................................

Girls —

12 years ........................................................................................................................

13 years ........................................................................................................................

14 years ........................................................................................................................

15 years ........................................................................................................................

16 years ........................................................................................................................

17 years ........................................................................................................................

Percentile points

White I Nearo

P75 I

P5o ’25 ’75 Ps o ’25

Bone-specific skeletal age range in monthsmale sta;dard

20.4

18.8

16.8

16.0

14.9

11.5

19.0

18.9

18,5

17.0

10.1

14.5

15.9

14.6

12.3

11.0

8.7

4.9

14.4

12.8

10.8

6.8

2.1

1.7

12.3

10.9

8.9

6.7

3.7

0.9

11.0

8.7

5.0

1.6

0.5

0.5

20.5

18.1

18.2

13,4

15.3

16.2

17.9

18.7

18.5

12,9

13.9

13.8

15.0

13.3

13,8

10.0

9.2

8.4

11.6

12.5

10.0

4,6

3.2

2.7

12.1

10.6

8.9

6.5

4.2

2.1

7.8

9.1

4,0

0.8

0.7

0.6

Table 13. Selectad percentiles in the distribution of the individual youth 'srange in bone-specific skeletal ages fortheradio-opaque (not

adult) bonas in the hand-wrist for youths bv geographic region, chronological a!sein years atlast~rthday.a ndsex: United States, ,..

1966-1970

Chronological age in years and sex

Bovs

12 years .................................................

13 years ..................o..............................

14 yaars .................................................

15 years .................................................

16 years .................................................

17 years .................................................

Girls —

12 years .................................................

13 years .................................................

14 years .................................................

15 years .........l .......................................

16 yaars ..................................... ............

17 years .................................................

Percentile points

Northeast Midwest South West

J’75 P5 o ’25 P75 P5 o ’25 P75 P50 ’25 f’75 P50 ’25

20.4

18,8

16.9

16.7

14.7

13.0

18.4

21.0

20.4

18.9

13.8

19.4

16.0

14.2

12.1

10.6

8.8

3.9

14.2

12.8

10.8

6.5

4.6

4.2

Bone-specific skelatal age range in months–male standard

12.1

10.6

8.8

6.1

5.0

0.7

10.6

8.3

6.2

1.4

0.7

0.6

20.4

18.6

16.2

15.6

16.0

13.7

18.9

18.9

18.1

18.7

8.7

16.9

15.7 12.3

14.4 12.0

12.4 8.6

11.3 7.5

8.6 4.1

6.5 2.2

14.7 11.9

12.8 8.8

10.5 4.1

6.7 2.3

1.0 0.5

3.0 0.6

20.3

17.7

18.2

14.1

13.2

9.7

18.7

18.1

18.5

13.7

8.2

6.9

15.0

14.2

12.6

10.1

8.5

5.2

13.0

12.4

10.7

4.6

0.9

0.9

12.3

10.1

8.8

6.5

2.7

0.9

8.9

8.2

5.0

0.8

0.5

0.5

20.3

19,1

16.7

16.4

16.4

12.9

20.0

20.1

18.4

16.0

10.9

12.1

16,1

15,5

12.5

12.0

10.3

5.1

13,7

12.9

10.6

9.5

2.6

0.9

12.3

12,1

9.4

6.4

3.9

0.9

10.4

9.8

5.3

2,4

0.6

0.4

86
Table 14. Selected percentiles in the distribution of theindividual youth's rengein bone-specitic skeletal agesfortheradio-opaque {not

adult) bones in the hand-wrist forvouths bv annual familv income, chronological age in years at last birthday, and sex: United

States, 1966-1970

Chronological age in years and sex

Boys

12 years ......................................................................................

13 years ,..,..,,,.,...!.,.. ...................................................................

14 years ......................................................................................

15 years ......................................................................................

16 years ......................................................................................

17 years ......................................................................................

Girls

12 years ......................................................................................

13 years ......................................................................................

14 years ......................................................................................

15 years ......................................................................................

16 years ,,..,..,., ,.,$...,....................................................................

17 years ......................................................................................

-.

Percentile points

Lessthan $5,000 I $5,000-$9,999 I $10,000 or more

I I

P75 P50 ’25 P75 P50 ’25 P75 P50 ’25

20.0

18.6

18.3

15.6

14.1

13.1

18.4

18.3

18.5

16.1

12.9

8.3

8one-specific skeletal age range in months–male standal

15.3

14.6

12.8

11.3

8.6

6.7

13.6

12.6

10.4

6.8

2.3

0.8

12.2

11.0

9.0

6.8

3.8

1.6

10.0

9.6

6.0

1.0

0.5

0.4

20.7

19.9

16.0

15.4

16.8

12.6

19.3

20.8

18.6

18.6

10.9

16.9

16.1

14.8

12.3

11.0

10.1

4.5

13.0

13.7

12.5

6.9

2.5

5.3

12.4

10.9

9.0

6.5

4.6

0.7

10.3

9.0

5.3

2.3

0.5

0.6

20.4

18.0

17.7

15.1

13.7

11.1

19.1

18.5

18.3

19.9

8.9

12.6

16.0

14.0

12.2

10.6

7.3

5.1

15.0

12.4

9.8

6.5

2.3

1.3

12.3

10.6

8.7

6.7

2.6

1.0

12.2

7.9

4.8

1.0

0.5

0.5

Table 15. Median (chronological) -- aqe of onset of ossification in selected hand-wrist bones for youths 12-17 vears by race, region, annual

family income, and sex: United States, 1966-1970 -

Race, region and annual family income

Race

White ..............................................................................................................................................

Negro ..............................................................................................................................................

Region

Northeast ........................................................................................................................................

Midwest ..........................................................................................................................................

South ..............................................................................................................................................

West .......m......m................................................................................................................................

Annual family income

Less than $5.000 ............................................................................................................................

$5,000-$9,999 ................................................................................................................................

$10,000 or more .............................................................................................................................

Boys I

Girls

Adductor I

Flexor I

Flexor

sesamoid sasamoid sesamoid

Chronological age in years

12.4

12.7

12.5

12.5

12.5

12.5

12.5

12.4

12.5

14.2

14.5

14.0

13.3

14.4

14.4

14.4

13.1

13.0

13.0

13.1

13.1

13.0

13.0

13.0

13.1

13.0

12.9

87
Table 16. Median age in months at epiphyseal fusion for selected hand-wrist bones of white and Negro boys and girls 12-17 years of

chronological age at last birthday: United States, 1966-1970

Hand-wrist bone

Radius .............................................................................................................................. ......................

Ulna ........................................................................................................................................................

Metacarpal I ............................................................................................................................................

Metacarpal II ..........................................................................................................................................

Metacarpal Ill .................................................. ................................................. ......................................

Metacarpal IV .............................................................................................................................. ...........

Metacarpal V .............................................................................................................................. ............

Proximal phalanx I ............ .....................................................................................................................

Proximal phalanx II ............................................ ...................................................................................

Proximal phalanx 111...............................................................................................................................

Proximal phalanx lV ...............................................................................................................................

Proximal phalanx V ................................................................................................................................

Middle phalanx II ...................................................................................................................................

Middle phalanx Ill ..................................................................................................................................

Middle phalanx IV ..................................................................................................................................

Middle phalanx V .............................................................................................................................. .....

Distal phalanx I ........................................................................................................................ ..............

Distal phalanx II .....................................................................................................................................

Distal phalanx 111....................................................................................................................................

Distal phalanx lV ....................................................................................................................................

Distal phalanx V ................................................................................................................................ .....

*

Median age in months

●

☛

190

198

199

199

199

195

191

193

193

190

193

196

196

195

188

189

189

187

188

●

194

165

178

178

179

180

168

168

169

169

168

167

169

! 69

168

162

162

162

161

161

*

●

194

199

198

198

199

198

194

196

196

196

197

199

198

198

188

188

188

187

188

●

192

167

176

175

174

175

170

171

171

171

171

171

171

172

171

160

160

161

159

161

*Estimates of median age not possible or not sufficiently reliable forpublication. Theradius had reached the “adult’’s tagef oronly

26percent of boys and53 percent ofgirls andtheulna in only 51 percent of boys by 17.9 years.

88
APPENDIXES

CONTENTS

I. Statistical Notes ................................................................................................................................. TO

The Suxvey Design........................................................................................................................

Reliability ..................................................................................................................................... 91

SampKng and Measurement Emor ................................................................................................. 92

Expected Values ........................................................................................................................... 93

Small Numbers ............................................................................................................................. 93

II. Demographic and Socioeconomic Terms ............................................................................................ 95

111. Reliability of Assessments .................................................................................................................. 97

Area Skeletal Ages ........................................................................................................................ 98

Bone-Specific Skeletal Ages .......................................................................................................... 98

Factors Influencing Replicabifity .................................................................................................. 98

LIST OF APPENDIX TABLES

I. The number of youths whose radiographs were assessed; the number not assessed refers to youth

who were examined but whose radiographs were missing or of poor quahty: Health Examination

Survey, 1966.1970 .......................................................................................................................... 92

II. Number of boys and girls for whom skelctaf age assessments were made on each of the 31 handwnst bones: Health Examination Survey, 1966.1970 ...................................................................... 93

111. Mean difference in cross- and self-replicate assessments of bone-specific skeletaf ages from handwrist radiographs of examinees 12-17 years old at last birthday, by reader: Health Examination

Survey, 1966.1970 .......................................................................................................................... 97

89
APPENDIX 1

STATISTICAL NOTES

The Survey Design

The sample design for the first three programs of Cycles I-III of the Health Examination

Survey has been essentially similar in that each

has been a multistage, stratified probability sample of clusters of households in land-based segments. The successive elements for this sample

design are primary sampling units, census enumeration district, segment (a cluster of households), eligible persons, and finally, the sample

person.

The 40 sample areas and the seagnents utilized in the design of Cycle III were the same as

those in Cycle II. Previous reports describe in

detail the sample design used for Cycle II and, in

addition, discuss the problems and considerations given to other types of sampling frames,

cluster versus random sampling, and whether or

not to control the selection of siblings.7 Y8

Requirements and limitations placed on the

design for Cycle III, similar to those for children

in Cycle II, were that:

1.

2.

The target population be defined as the

civilian noninstitutionalized population

of the United States, including A1aska

and Hawaii, between the ages of 12 and

17 years for Cycle III, with the special

exclusion of children residing on reservation lands of the American Indians. The

latter exclusion was due to operational

problems encountered on these lands in

Cycle I.

The time period of data collection be

limited to “about 3 years for each cycle

and the length of the individual examinaNOTE: A list of references follows the text.

90

3.

4.

5.

tion within the specially constructed

mobile examination center be between

2 and 3 hours.

Ancillary data be collected on specially

desi~ed household, medical history and

school questionnaires, and from birth

certificate copies.

Examination objectives be primarily related to factors of physical and intellectual growth and development.

The sample be sufficiently large to yield

reliable ~indings within b;oad ~eographic

re~ons and population density groups as

well as age, sex, and limited socioeconomic groups for the total sample.

The sample was drawn jointly with the U.S.

Bureau of the Census starting with the 1960

decennial census list of addresses and the nearly

1,900 primary sampling units (PSU’S) into which

the entire United States was divided. Each PSU

is either a standard metropolitan statistical area

(SMSA), a county, or a group of two or three

contiguous counties. These PSU’S were grouped

into 40 strata, each stratum having an average

size of about 4.5 million persons, in such a manner as to maximize the degree of homogeneity

within strata with regard to the population size

of the PSU’S, degree of urbanization, geographic

proximity, and degree of industrialization. The

40 strata were then classified into 4 broad geographic regions of 10 strata each and then within

each region, cross-classified by four population

density classes and classes of rate of population

change from 1950 to 1960. Using a modified

Goodman-Kish controlled-selection technique,

one PSU was drawn from each of the 40 strata.
Further stages of sampling within PSU’S

required first the selection of census enumeration districts (ED’s). The ED’s me small welldefined areas of about 250 housing units into

which the entire Nation was divided for the

1960 population census. Each ED was assigned a

“measure of size” equal to the rounded whole

number resulting from a “division by nine” of

the number of children, age 5-9, in the ED at the

time of the 1960 census. A sample of 20 ED’s in

the sample PSU was selected by systematic sampling with each ED having a probability of selection proportional to the population of children

5-9 years at the time of the 1960 census date. A

further random selection by size of segments

(smaller clusters of housing units) within each

ED was then made.

Because of the 3-year time interval between

Cycle II and Cycle III, the Cycle III frame had

to be supplemented for new construction and to

compensate for segments where housing was partiaIly or totally demolished to make room for

highway construction or urban redevelopment.

Advanced planning for the examinations at

the various locations or stands provided for

about 17 days of examinations which limited

the number of examinees per location to approximately 200. When the number of eligible

youths in the sample drawn for a particular location exceeded this number, sub sampling was

done by deleting from the master list of eligible

youths (ordered by segment, household order

within segment, and age within household) every

nth name on the list starting with the yth name,

y being a number between 1 and n selected randomly and n being the extent of oversampling in

the original draw.

In Cycle III, as in Cycle II, twins who were

deleted in the sample selection were also scheduled for examination, time permitting, as were

youths deleted from the Cycle III sample who

had been examined in Cycle II. The sample was

selected in Cycle III, as it had been for the children in Cycle II, so as to contain the correct

proportion of youths from families having only

one eligible youth, two eligible youths, and so

on to be representative of the total target population. However, since households were one of

the elements in the sample frame, the number of

related youths in the resultant sample is greater

than would come from a design which sampled

youths 12-17 years without regard to household.

The resultant estimated mean measurements or

rates should be unbiased but their sampling variability will be somewhat greater than those from

more costly, time-consuming systematic sample

design in which every kth youth would be

selected.

The total probability sample for Cycle III

included 7,514 youths representative of the

approximately 22.7 million noninstitutionalized

U.S. youths of 12-17 years. The sample contained youths from 25 different States and

approximately 1,000 in each single year of age.

The response rate in Cycle III was 90 percent, with 6,768 youths examined out of the

total sample. These examinees were closely

representative of those in the samples as well as

the population from which the samples were

drawn with respect to age, sex, race, region, population density, and population growth in area

of residence. Hence it appears unlikely that nonresponse could bias the findings appreciably.

Measures used to control the quality of

the data from these surveys have been

cited ;T~s~194~195 these additional measures

specifically related to skeletal age are outlined

earlier in this report.

Reliability

Although measurement processes in the surveys were carefully standardized and closely

controlled, the correspondence between the real

world and survey results cannot be expected to

be exact. Survey data are imperfect for three

major reasons: (1) results are subject to sampling

error, (2) the actual conduct of a survey never

agrees perfectly with the design, and (3) the

measurement processes themselves are inexact

even though standardized and controlled.

The first report on Cycle 1118 describes in

detail the faithfulness with which the sampling

design was carried out.

Data recorded for each sample youth are

inflated in the estimation process to characterize

the larger universe of which the sample youth is

representative. The weights used in this inflation

process are a product of the reciprocal of the

probability of selecting the youth, an adjustment for nonresponse cases, and a poststratified

ratio adjustment which increases precision by

bringing survey results into closer alignment

91
with known U.S. population figures by color

and sex within single years of age 12 through 17

for the youths’ survey.

Ln the third cycle of the Health Examination

Survey (as for the children in Cycle II) the samples were the result of three principal stages of

selection—the single PSU from each stratum, the

20 segments from each sample PSU, and the

sample youth from the eligible persons.1 96 Y197

The probability of selecting an individual youth

is the product of the probability of selection at

each stage.

Since the strata are roughly equal in population size and a nearly equal number of sample

youths were examined in each of the sample

PSU’S, the sample design is essentially selfweighting with respect to the target population;

that is, each youth 12 through 17 years had

about the same probability of being drawn into

the respective samples.

The adjustment upward for nonresponse is

intended to minimize the impact of nonresponse

on final estimates by imputing to nonresp ondents the characteristics of “similar” respondents.

Here “similar” respondents were judged to be

examined youths in a sample PSU having the

same age (in years) and sex as youths not examined in that sample PSU.

The poststratified ratio adjustment used in

the third cycle achieved most of the gains in

precision that would have been attained if the

sample had been drawn from a population stratified by age, color, and sex and makes the final

sample estimates of population agree exactly

with independent controls prepared by the Bureau of the Census for the U.S. noninstitutionalized population as of March 9, 1968

(approximate midsurvey point for Cycle III) by

color and sex for each single year of age 12-17.

The weights of every responding sample youth

in each of the 24 age, color, and sex classes is

adjusted upward or downward so that the

weighted total within the class equals the independent population control for each survey.

In addition to youths not examined at all,

there were 32 for whom there was no radiograph

or else the radiograph could not be assessed. The

age and sex distribution for these 32 youths as

well as for the 6,736 for whom assessments were

made is shown in table I. The skeletal ages for

these youths without usable radiographs were

Table 1, The number of youths whose radiographs were assessed;

the number not assessed refers to youths who were examined but whose radiographs were missing or of poor

quality: Health Examination Survey, 1966-1970

Age

Total .........................

12 years ...............................

13 years ...............................

14 years ...............................

15 years ...............................

16 years ...............................

17 years ...............................

3,534

840

625

617

610

555

487

Number of youths

3,202

543

582

584

503

528

462

11

3

1

1

3

1

2

21

4

2

8

7

not estimated. It is assumed that the distribution

of their skeletal ages is similar to that for the

remaining 6,736. In other words, they were

treated as nonresponders.

Sampling and Measurement Error

In the present report, reference has been

made to efforts to minimize bias and variability

of measurement techniques.

The probability design of the survey makes

possible the calculation of sampling errors. The

sampling error is used here to determine how

imprecise the survey test results may be because

they come from a sample rather than from the

measurements of all elements in the universe.

The estimation of sampling errors for a

study of the type of the Health Examination

Survey is difficult for at least three reasons: (1)

measurement error and “pure” sampling error

are confounded in the data—it is not easy to find

a procedure which will either completely include

both or treat one or the other separately, (2) the

survey design and estimation procedure are complex and accordingly require computationally

involved techniques for the calculation of variances, and (3) from the survey are coming thousands of statistics, many for subclasses of the

population for which there are a small number

of cases. Estimates of sampling error are obtained from the sample data and are themselves

subject to sampling error which may be large

when the number of cases in a cell is small or

92
evsm occasionally when the number of cases is

substantial.

Estimates of approximate sarnplingvariability for selected statistics used in this report are

included in the detailed tables. These estimates

have been prepared by a replication technique

that yields overall variability through observation of variability among random subsarnples of

the total sample. The method reflects both

“pure” sampling variance and a part of the measurement variance.

In accordance with usual practice, the interval estimate for any statistic may be considered

the range within 1 standard error of the tabulated statistic, with 68-percent confidence; or

the range within 2 standard errors of the tabulated statistic, with 95-percent confidence. The

latter is used as the level of significance in this

report.

An approximation of the standard error of a

difference d = x - y of two statistics x and y is

,giwm by the formula

Sd = (s%2+ s;)%

where SX and SY are the sampIing errors, respectively, of x and y. Of course, where the two

groups of measures are positively or negatively

correlated, this will give an overestimate or

underestimate, respectively, of the actual

standard error.

Expected Values

In the detailed tables both the actual and

cxpcctcd mean skeletal ages are shown for children in the various demographic groups. The

expected mean values are obtained by assuming

that the national age-specific mean values apply

within the appropriate age subgroup for which

the value is derived.

For example, if in an area (e.g., the Northeast ), estimates from the Health Examination

Survey show ni boys in the ith age group

(i=l,2,..., 6; ~ ni = n) and the estimates of

mean skeletal age for all U.S. boys in the ith age

group to be <Yi>then the expected mean skeletal

age for boys in that area is:

The specific area may have higher values for

younger boys and lower values for older boys

than in the other areas. In that case, the expected average may obliterate one or both of

these differentials. These types of limitations

need to be kept in mind in interpreting these

data. The standard error of the difference between an actual and an expected mean value

may be approximated by the standard error of

the actual value.

Table II. Number of boys and girls for whom skeletal age assessments were made on each of the 31 hand-wrist bones:

Health Examination Survey, 1966-1970

Bone

Radius ................................

Ulna ...................................

Cavitate ..............................

Hamate ...............................

Triquetral ...........................

Lunate ................................

Scaphoid ............................

Trapezium ..........................

Trapezoid ...........................

Metacarpal 1 .......................

Metacarpal II ......................

Metacarpal [[l .....................

Matacarpai IV .....................

Metacarpal V ......................

Proximal phalanx 1.............

Proximal phalanx I 1............

Proximal phalanx Ill ..........

Proximal phalanx IV ..........

Proximal phalanx V ............

Middle phalanx II ...............

Middle phalanx Ill ..............

Middle phalanx IV ..............

Middle phalanx V ...............

Distal phalanx 1..................

Distal phalanx I l .................

Distal phalanx Ill ...............

Distal phalanx IV ...............

Distal phalanx V .................

Pisiform ..............................

Adductor sesamoid .............

Flexor sesamoid .................

Number

3,445

3,286

2,011

1,986

2,007

2,000

2,017

2,007

1,995

2,448

2,759

2,738

2,729

2,799

2,638

2,588

2,591

2,584

2,576

2,618

2,651

2,648

2,625

2,296

2,339

2,335

2,298

2,307

1,773

1,511

1,095

2,977

2,407

759

741

752

756

776

780

768

1,128

1,590

1,560

1,577

1,701

1,398

1,319

1,346

1,350

1,327

1,316

1,372

1,377

1,292

968

982

974

893

893

744

908

746

11

11

1

1

2

3

1

2

2

1

1

1

1

2

2

1

1

1

1

1

1

1

1

1

2

2

1

2

166

574

1,052

6

4

1

1

1

1

1

1

1

1

1

1

1

1

3

1

1

1

1

1

1

1

2

3

1

2

1

1

10

25

264

93
Small Numbers

In some tables, magnitudes are shown for

cells for which the sample size is so small that

the sampling error may be several times as great

as the statistic itself. Obviously, in such instances the statistic has no meaning in itself

except to indicate that the true quantity is

small. Such numbers, if shown, have been included in the belief that they may help to convey an impression of the overall story of the

table.

Among the 6,736 children with usable radiographs, there were a few of inadequate quality

to permit assessment of all bones. In general,

these would have been bones that became radioopaque recently or bones near the margin of the

radiographic field. The number of youths for

whom bone-specific skeletal ages were assigned

and the numbers in which particular bones were

adult are shown in table II.

000

94
APPENDIX II

DEMOGRAPHIC AND SOCIOECONOMIC TERMS

Age. –The age recorded for each youth was

the age at last birthday on the date of examination. The age criterion for inclusion in the sample used in this survey was defined in terms of

age at time of interview. Since the examination

usually took place 2-4 weeks after the interview,

some of those who were 17 years old at the time

of interview became 18 years old by the time of

examination. There were 23 such cases. In the

adjustment and weighting procedures used to

produce national estimates these 23 were included in the 17-year-old group.

Race. –Race was recorded as “white,”

“Negro,” or “other. “ “Other” included American Indians, Chinese, Japanese, and all races

other than white or Negro. Mexican persons

were included with “white” unless definitely

known to be American Indian or of other nonwhite race. Negroes and persons of mixed Negro

and other parentage were recorded as “Negro. ”

Geographic region. –For purposes of stratification, the United States was divided into four

broad geographic regions of approximately equal

population. These regions, which correspond

closely to those used by the Bureau of the

Census, were as follows:

Rc@”on

Northeast . . . . .

Midwest. . . . . . .

States included

Maine, Vermont, New Hampshire, Massachusettss, Connecticut, Rhode Island, New

York, New Jersey, and Pennsylvania

Ohio, Illinois, Indiana, Michigan, Wisconsin, Minnesota,

Iowa, and Missouri

South . . . . . . . . Delaware, Maryland, District

of Columbia, West Virginia,

Virginia, Kentucky, Tennessee, North Carolina, South

Carolina, Georgia, Florida,

Alabama, Mississippi, Louisiana, and Arkansas

West: . . . . . . . . Washington, Oregon, California, Nevada, New Mexico,

Arizona, Texas, Oklahoma,

Kansas, Nebraska, North Dakota, South Dakota, Idaho,

Utah, Colorado, Montana,

Wyoming, Alaska, and Hawaii

Urban-rural. –The definition of urban-rural

areas was the same as that used in the 1960

Census. According to this definition, the urban

population was comprised of all persons living in

(a) places of 2,500 inhabitants or more incorporated as cities, boroughs, villages, and towns

(except towns in New England, New York, and

Wisconsin); (b) the densely settled urban fringe,

whether incorporated or unincorporated of

urbanized areas; (c) towns in New England and

townships in New Jersey and Pennsylvania that

contained no incorporated municipalities as subdivisions and had either 2,500 inhabitants or

more, or a population of 2,500 to 25,000 and a

density of 1,500 persons or more per square

mile; (d) counties in States other than the New

England States, New Jersey, and Pennsylvania

that had no incorporated municipalities within

their boundaries and had a density of 1,500 persons or more per square mile; and (e) unincorporated places of 2,500 inhabitants or more not

included in any urban fringe. The remaining

population was classified as rural.

95
Urban areas are further classified by population size for places within urbanized areas and

other urban places outside urbanized areas.

Grade in school. –The grade that the youth

attended at the time of interview was used here

and later verified against school records. The

grade of those youths on summer vacation was

considered to be the grade that they would enter

when school resumed.

Education of parent or guardian. –This was

recorded as the highest grade completed in

school. The only grades counted were those

attended in a regular school where persons were

given formal education in graded public or private schools, whether day or night school, and

whether attendance was full or part time. A

“regular” school is one that advances a person

toward an elementary or high school diploma, or

a college, university, or professional school

degree. Education in vocational, trade, or business schools outside the regular school system

was not counted in determining the highest

grade of school completed.

Family income. –The income recorded was

the total income of the past 12 months received

by the head of the household and all other

o

household members related

blood, marriage, or adoption.

to the head by

This income was

the gross cas~ income (excluding pay in kind)

except in the case of a family with their own

farm or business, in which case net income was

recorded.

Parent. –A parent was the natural parent or,

in the case of adoption, the legal parent of the

youth.

Guardian. –A guardian was responsible for

the care and supervision of the youth. He (or

she) did not have to be the legal guardian to bc

considered the guardian for this survey. A guardianship could only exist when the parent(s) of

the youth did not reside within the sample

household.

Head of household. –OnIy one person in

each household was designated as the “head.”

He (or she) was the person who was regarded as

the “head” by the members of the household. In

most cases the head was the chief breadwinner

of the family, although this was not always true.

In some cases the head was the parent of the

chief earner, or

household.

00

the only adult member of the

96
APPENDIX Ill

RELIABILITY OF ASSESSMENTS

T(J provide the basis for determining the

h.wl of reliability of the bone-specified skeletal

:i,~c’ assessments made by the nine medical students at Case Western Reserve University from

hand-wrist radiographs of the 12-1 7-year-old

youths examined in the Health Examination

Survey of 1966-1970, a randomly selected ‘sample of 1 in 23 radiographs was reassessed by the

same reuder and approximately 1 in 20 indepcmdcntly randomly selected radiographs were

reassessed by another reader, as described previ(msly. All nine readers, before starting these

find assessments, had been trained by Dr. Pyle

in the Greulich-Pyle method using the “HES

Standard” to the point that their assessments

were in close agreement with hers. In all, 351

SC*1f-n.’plicate assessments and 301 cross-replicate

assessments were made. Each reader made

:Ipproximately the same number of self-replicate

:tnd cross-replicate assessments.

All nine readers maintained a high level of

consistency in their own assessments throughout

all 40 examination stands of the survey. The

mean difference in self-replicate assessments for

all nine readers was 0.1 month for all 31 bones

as well as for the 28 bones from which those

that were late to ossify (the pisiform, adductor

sesamoid and flexor sesamoid) were excluded.

Considering data for all 31 bones, the mean difference per reader between original and selfreplicate assessments ranged from 0.2 to 1.7

months combining data from both sexes. For

the 28 bones that ossify relatively early, the

mean differences range from 0.2 to 1.6 months

among the nine readers (table III).

A consistently high level of agreement in

bone-specific skeletal age assessments was maintained among the nine readers but the level was,

as expected, somewhat lower than that for the

individual readers with themselves. The mean

Table I I 1. Mean difference in cross- and self-replicate assessments of bone-specif ic skeletal ages f rom hand-wrists radiographs of examinees

12-17 years old at last birthday, by reader: Health Examination Survey, 1966-1970

Reader

All readers .................................................................................................

Reader 21 ..................................................................................................................

Reader 22 ..................................................................................................................

Reader 24 ..................................................................................................................

Reader 25 ..................................................................................................................

Fk?ader 26 ..................................................................................................................

Reader 27 ..................................................................................................................

Reader 28 ..................................................................................................................

Reader 29 ..................................................................................................................

Reader 30 ..................................................................................................................

Self- CrossNumber

of films

replicates replicates replicated

31 28 31 28

oones bones bones bones Self Cross

Mean difference

-0.1

1.6

-1.2

-1.7

0.5

-0.2

-0.3

0.3

0.2

-1.0

-0.1

1.6

-1.4

-1.6

0.4

-0.2

-0.3

0.2

0.3

-1.0

===+== 1=351

L

0.7 0.8

-2.3 -2.1

-1.7 -1.6

2.6 2.4

-0.8 -0.5

-1.5 -1.7

1.0 1.3

-1.0 -0.8

-1.3 -1.0

36

36

21

66

44

44

44

30

30

301

32

30

20

56

32

43

33

27

28

97
cross-replicate

bones was 0.2

difference for all 31 hand-wrist

month. It ranged between 0.7 and

2.6 months for the readers: When only the 28

centers that are relatively early to ossify were

considered, the overall mean difference was

slightly less–O. 1 month–and ranged from 0.8 to

2.4 months among the individual readers.

The aspects considered include consistency

wit hi n observers (intraobserver differences),

comparability between observers (interobserver

differences), and differences resulting from variations in the way the Greulich-Pyle Atlas has

been used. This review is restricted to reports

based on samples of at least 10 radiographs and

to the chronological age range 12-17 years.

Although it is impossible at present to determine the true maturity level of the bones visualized in a radiograph, it is necessary to define the

reliability of assessments both within and between observers. As stated by Greulich and

Pyle: 10 “Though the ability to duplicate assessments with a good degree of consistency must

be possessed by a competent assessor, it alone is

not enough. It is even more important that the

assessments be made correctly, that is, that they

be made according to the method recommended

by the particular radiographic atlas on which

they purport to be based. ” Unfortunately, the

suggestion by Moorel 9 G that sets of duplicate

radiographs that have been assessed by recognized experts be available to those who wish to

measure their level of comparability has not

been implemented.

Area Skeletal Age

It is not easy to compare reported findings

because workers have analyzed their data in different ways. For intraobserver differences,

95-percent confidence limits of 7.2 monthsl97

and mean differences ranging from 1.2 to 6.6

months have been reported,z 8~19 S‘z OI in addition to variable errors to 1,4 to 4.2

months.z0z~z03 The median intraobserver differences range from zero to 4 months.z OA~zOs A

report of zero median differences seems surprising but it is possible because Moed and his coworkers made overall assessments to the nearest

atlas standard.

Todd’sl 8 claim that interobserver differences less than 6 months could be achieved readily appears justified. Reported mean interobserver differences range from 1.3 to 4.2

months.zOO~zOG~zO T In addition, a root mean

square of 6.2 months and confidence limits of

7.4 months have been reported.1 g T~z01 Reported incidence of particular interobserver differences indicate that the medians were less than

3 months for the study by Hansman and

MareshG G and less than 6 months for the study

by Moed et al.zOA

Bone-Specific Skeletal Ages

Moorel96 reported interobserver differences

that were Iess than 12 months in 94 percent of

bones.

Factors Influencing Replicability

There is no indication that the level of replicability is related to the differences between

chronological and skeletal ages. 199 ~z02 However, the range of maturity between the bones of

a hand-wrist influences the replicabilit y of overall but not bone-specific assessments.19 9‘2 00

The quality of the radiographs (exposure, positioning) has no effect on replicability within the

range that is common in research studiesz00 but

unusually poor radiographic quality does reduce

replicability.z 0z The method by which the

Greulich-Pyle Atlas is used has an effect.

Maresh22 reported a technical error of 3.0

months between overall assessments and those

obtained as the means of bone-specific skeletal

ages.

NOTE: A list of references follows the text.

98
Series 1.

Series 2.

Series 3.

Series 4.

VITAL AND HEALTH STATISTICS Series

Programs and Collection Procedures. –Reports which describe the general programs of the National

Center for Health Statistics and its offices and divisions and data collection methods used and include

definitions and other material necessa~ for understanding the data.

Data Evaluation and Methods Research. –Studies of new statistical methodology including experimental tests of new survey methods, studies of vital statistics collection methods, new analytical

techniques, objective evaluations of reliability of coIlected data, and contributions to statistical theory.

Analytical Studies. –Reports presenting analytical or interpretive studies based on vital and health

statistics, carrying the analysis further than the expository types of reports in the other series.

Documents and Committee Reborts. –Final reports of maior committees concerned with vital and

/

health statistics and documents- such as recommended moc&l vital registration laws and revised birth

and death certificates.

Series 20. Data From ~the Health Interview Sumey. –Statistics on illness, accidental injuries, disability, use of

hospital, medical, dental, and other services, and other health-related topics, all based on data collected

in a continuing national household interview survey.

Series 11. Data From the Health Examination Survey and the Health and Nutrition Examination Survey. –Data

from direct examination, testing, and measurement of national samples of the civilian noninstitutionalized population provide the basis for two types of reports: (1) estimates of the medically defined

prevalence ,of specific diseases in the United States and the distributions of the population with respect

to physical; physiological, and psychological characteristics and (2) analysis of relationships among the

various measurements witbout reference to an explicit finite universe of persons.

Series 12. Data From the Institutionalized Population Surveys. –Discontinued effective 1975. Future reports from

these surveys will be in Series 13.

Series 13. Data on Health Resources Utilization. –Statistics on the utilization of health manpower and facilities

providing long-term case, ambulatory care, hospital care, and family planning services.

Series 14. Data on Health Resources: Manpower and Facilities. –Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health

occupations, hospitals, nursing homes, and outpatient facilities.

Series 20. Data on Mortality. –Various statistics on mortality other than as included in regular annual or monthly

reports. Special analyses by cause of death, age, and other demographic variables; geographic and time

series analyses; and statistics on characteristics of deaths not available from the vitaI records based on

sample surveys of those records.

Series 21. Data on Natality, Marriage, and Divorce. –Various statistics on natality, marriage, and divorce other

than as included in regular annual or monthly reports. Special analyses by demographic variables;

geographic and time series analyses; studies of fertility; and statistics on characteristics of births not

available from the vital records based on sample surveys of those records.

Sm”es 22. Data From the National Mortality and Natality Surveys.–Discontinued effective 1975. Future reports

from these sample surveys based on vital records will be included in Series 20 and 21, respectively.

Sm”es 23. Data From the National Survey of Family Growth. –Statistics on fertility, family formation and dissolution, family planning, and related maternal and infant health topics derived from a biennial survey

of a nationwide probabtiity sample of ever-married women 15-44 years of age.

For a list of titles of reports published in these series, write to: Scientific and Technical Information Branch

National Center for Health Statistics

Public Health Service

Hyattsville, Md. 20782

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