Data from the

NATIONAL HEALTH SURVEY

Skeletal Maturity Of

Youths 12-17 Years

United States

Skeletal age (hand-wrist), onset of ossification

and bone-specific skeletal ages by chronological age and sex of boys and girls 12-17 years

of age as assessedby the Health Examination

Survey Standard based primarily on the

Greulich-Pyle Radiographic Atlas.

DHEW Publication No. (H RA) 77-1642

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

Public Health Service

Series 11

Number 160

Health ResourcesAdministration

National Center for Health Statistics

Rockville, Md. November 1976
.—

Library of Congress Cataloging in Publication Data

Roche, Alex F

Skeletal maturity of youths 12-17 years, United States.

(Vital and health statistics: Series 11, Data from the National Health Survey; no. 160)

(DHEW publication; no. (HRA) 77-1642)

Includes bibliographical references.

1. Youth–United States–Growth. 2. Bone–Growth. 3. Man-Age determination.

L 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. 160.

V. Series: United States. Dept. of Health, Education, and Welfare. DHEW publication; no.

(HRA) 77-1642. [DNLM: 1. Age determination by Skeleton–In adolescence. 2. Bone development–In adolescence. W2 A N148vk no. 160]

RA407.3.A347 no. 160 [RJ140] 312’.’973s 76-5857

ISBN 0-8406 -0070-4 [312’.6]

.—

For sale by the Superintendent of Documents, U.S. Government Printiug Office, Washington, D.C. 20402- Price $1.55
NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

ROBERT A. ISRAEL, Deputy Director

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

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

ELIJAH L. WHITE, Associate Director for Data Systems

GEORGE P, FAILLA, Associate Director for Management

PETER L, HURLEY, Associate Director for Operations

JAMES M. ROBEY, Ph.D., Associate Director for Program Development

ALICE HAYWOOD, Information Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

ARTHUR J. McDOWELL, Director

JEAN-PIERRE HABICHT, M.D., Ph.D., Special Assistant to Director

PETER V. V. HAMILL, M.D., Medical Adviser

JEAN ROBERTS, Chief Medical Statistics Branch

ROBERT S. MURPHY, Chief Survey Planning and Development Branch

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specifications established by the National Center for Health Statistics,

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 certtin P~S of

the statistical processing.

Vital and Health Statistics - Series 1l-No. 160

DHEW Publication No. (HRA) 77-1642

Library of Congress Catalog Card Number 76-5857
CONTENTS

Page

Introduction ----------------------------------------------------------

The Nature of Skeletal Maturation --------------------------- -----------

Histological Changes -----------------------------------------------

Radiographic Changes --------------------------- -------------------

Scale of Maturity ------------------- ------------------ --------------

The Usefulness of Skeletal Maturi~ Assessments -----------------------

The Health Examination Survey Standard --------------------------- -----

Method . . --------------------------- ---------------------------- ------

Field Radiography - --------------------------- --------- ------------

Training of Assessors ----------------------------------------------

Assessment Procedure --------------------- ------- -------------- ---

Findings - ---------------- -----”-” ------- -------- -------- *------ ------

Skeletal Age (H=d-Wrist) ------------------------------------------

Bone-Specific Skeletal Ages -----------------------------------------

Range of Bone-Specific Skeletal Ages --------------------------------

Onset of Ossification -----------------------------------------------

Epiphyseal Fusion --------------------------- ------------------ -----

Youths Also Examined as Children --------------------------- ----------

Discussion “—------ --------------------------- ------------------------

Mean Skeletal Age (Hand-Wrist) ------------------- ------------------ -

Variability of Means -------------------- -------------------- --------

Bone-Specific Skeletal Ages -------------------- -------------------- -

Onset of Ossification --------- --------------- -------- ----------------

Epiphyseal Fusion --------------------------------------------------

Youths Also Examined as ChiMren ---------- -------------------------

Conclusion ------- --------------- --------------- -------- ------------

Summary - ----.-------” ----- “-------- --------------------------- -----

Epiphyseal Fusion ----------.------------” ------------ --------------

Youths Also Examined as Chiltien -----------------------------------

References ---.” ---------------------- “-------- ------------.---” -------

List of Detailed Tables ---------------------- ------- -------------------

1

3

3

5

5

6

8

8

9

9

10

11

11

23

28

28

30

32

34

36

41

41

43

43

43

44

44

45

45

47

53

ill
Page

Appendix I. Statistical Notes ------------------ ----- ”--- . --- . -- .------” 85

The Survey Design --------------------- ------- . ----------- ..---”---- 85

Reliabili~--------------------------------------------------------- 86

Sampling and Measurement Error --------------------------- --------- 87

Small Numbers ----” ---------------------- --------- ---------------- 87

Appendix II. Reliability of Assessments ---------------------------- ---- 89

Area Skeletal Ages -------- ------- -------------- -------------------- 90

Bone-Specific Skeletal Ages --------------------------- -------------- 90

Factors Influencing Replicabili~------------------------------------- 90

SYMBOLS

Data not available -------------------------------------- ---

Category nonapplicable ------------------------------- . . .

Quantity zero --------------------------------------------- -

Quantity morethan Obutless than 0.05----- 0.0

Figure does not meet standards of

reliability or precision ------------------------------ *
SKELETALMATURITY OF YOUTHS

12-17YEARS

tiexF. Roche, M.D., Fek Research Insitute, Jean Roberts and Peter V. V. Hard, M.D., Division of Health Examination Statistics

INTRODUCTION

This report presents national estimates of

the levels of skeletal maturity of the hand-wrist

for noninstitutionalized United States youths age

12-17 years based on findings from the Health

Examination Survey of 1966-70. This is the first

time estimates of skeletal maturity have been

made for the youth age span in this or any other

country, but national estimates from a corresponding study of children age 6-11 years in the

United States in 1963-65 have been reported previously. 1,2 These national studies provide estimates of known reliability against which future

possible changes in skeletal maturation rates for

the country as a whole can be judged.

The Health Examination Survey is one of the

major programs of the National Center for Health

Statistics authorized under the National Health

Survey Act of 1956 by the 84th Congress as a continuing Public Health Service function to determine

the health status of the United States population.

Four types of survey programs are used to

carry out the intent of the National Health Survey.3

The Health Interview Survey, collecting information from samples of people by household interview, is focused 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

diagnostic data on the prevalence of certain medically defined illnesses. 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. It also collects demographic and socioeconomic data on 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. 4’5

For the second cycle or program, a probabilityy sample of the noninstitutionalized children 6-11

years of age in the United States was selected and

examined in 1963-65. The examination in this

cross- sectional study primarily assessed health

factors related to growth and development as described in a previous report. G

The third cycle, on which findings in this report are based, was designed as in the preceding

childrenls program to collect data on the health

status of the youth population with particular emphasis on factors and conditions related to their

growth and development. For this, a probability

sample of the noninstitutionalized youths 12-17

1
years in the United States was selected for examination. The questionnaires and examination content and procedures were similar enough to those

in the children’s program to obtain comparable information through adolescence for many variables

but were supplemented, as necessary, to obtain

data specifically related to adolescent health. Included were a physical examination given by a

pediat=ian 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. The survey plan, sample design, examination content, and operation of

this survey program have been described in a previous report.7

Field collection operations for this youths’

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

sample, 6,768 youths, or 90 percent, were ex-

~amined.. This national sample is representative,

and the examined group closely representative, of

the 22.7 million noninstitutionalized youths 12-17

years of age in the United States with respect to

age, sex, race, geographic region, population size

of place of residence, and rate of change in size of

population 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 latter study had been

examined in the children’s survey also. The time

lapse between the two examinations ranged from

28 months to 5 years with a median lapse of about

4 years.

The examinations were conducted consecutively in 40 different locations throughout the

United States. During his single visit, each youth

was given a standardized examination by the team

in the mobile units specially designed for use in

the survey. The only examinees given any additional followup procedures were girls whose urine

specimens were found m be positive for bacteriuria, who were then brought back for repeat

urine tests. Prior to the examination, demographic

and socioeconomic data on household members as

well as medical history, behavioral, and related

data on the youth to be examined were obtained

from his parents. Also an additional Health Habits

and History form was completed by the youth before he arrived for the examination and a Health

Behavior form was completed by him while in the

examination center. Ancillary data were requested

from the school attended by the youth, including

his grade placement, teacher’s ratings of his behavior and adjustment, and heaIth problems known

to his teacher. A birth certificate was obtained

for each youth for verification of his age and for

information related to his condition at birth.

As for the preceding na?ional survey among

children, some measure of skeletal age or maturation was considered essential to this study of

health factors related to the normal growth and

development of youths. In planning for the preceding study among children, the advice of clinicians and directors of long-term studies of growth

and development had been obtained about possible

uses of skeletal maturity levels and methods of

assessing skeletal age from radiographs, Drs.

William Walter Greulich and Harold C. Stuart,

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, had recommended that Dr.

S. Idell Pyle assemble a standard for the assessment of skeletal maturity from their radiographic

series, specifically for use in the National Health

Examination Survey.

At the formal request of the National Center

for Health Statistics, the 1964 manual—the preliminary edition of The Radiographic Standard of

Reference for the Growing Hand and WristE—was

prepared for this purpose by Dr. Pyle and Dr.

Greulich in collaboration with Dr. Alice Waterhouse, then Medical Advisor to the National Center for Health Statistics. This manual will be referred to in this report as the “HES Standard. ”

Bone-specific skeletal age assessments of the

hand-wrist radiographs were made by medical

students with special training in this method at

Case Western Reserve University under the

supervision of Dr. Pyle.

The same measure of skeletal maturation

used in the preceding children’s program was

used in the youths’ examination program also.

The general concept of skeletal maturity, the

methodology by which radiographs were taken and

later assessed, and the quality control measures

used were all identical to those in the children’s

study and have been described and discussed in

2
the first report on skeletal maturity of children

6-11 years.1

The present analysis concerns age and sex

differences in skeletal maturity levels for the

United States population 12-17 years. For this

purpose, satisfactory radiographs were available

for assessment for 6,736 of the 6,768 examined

youths. This represents 99.5 percent of the

examined youths or 89.6 percent of the total

probability sample selected forthenational study.

Among the youths examined, only 32 were not

radiographed or had radiographs taken attheexamination that were unsuitable for assesment.

Statistical notes on the sample design, reliability of the data, and sampling error are included in appendix 1.

THE NATURE OF

SKELETAL MATURATION

Generally, maturation of the skeleton is considered to begin when skeletal rudiments can be

recognized first in the embryo; maturation is complete when comparative stability of skeletal form

and function is attained in young adulthood. During maturation there is an increase in the number

of specialized cells and biochemical mechanisms

become more complex. The skeletal changes during senescence include a reduction in the number

of specialized cells; this can be described as a

negative phase of maturation.

Histological Changes

Maturation of a long bone commences when

some embryonic connective tissue in a limb bud

condenses to form a model.g The condensed connective tissue of the model is replaced by cartilage; this occurs first in the central part of each

model.l” The connective tissue around this cartilage becomes a well-defined layer called the

perichondrium, the inner layer of which contains

cells that can mature into chondrocytes or osteocytes. These cartilaginous models resemble in

shape the adult bones they precede,ll’12 and

they enlarge by apposition from the perichondrium, from the connective tissue related to their

ends, and by the division of chondrocytes within

the model.l”

The chondrocytes in the central parts of the

models hypertrophy and vacuolize at about the

sixth prenatal week1°’13’14(asshown in figure l-A).

The later calcification of this area15’16 constitutes

the first stage of skeletal maturation that can be

observed radiographically. The area of hypertrophic chondrocytes and calcified cartilage enlarges

more rapidly than the model. Consequently, these

areas occupy a greater proportion of the model

(figure l-B). Ossification commences when a collar of bone forms deep to the perichondrium

around the central part of the cartilaginous model

(figure 1-B). Soon afterwards, ossification begins

in the central part of the model by replacement of

calcified cartilage (figure 1-C). The early stages

k

/

F------ /

/

FiLrous

P

tissue

Cartilage

.;a;: :.,?..

:?s’;

,>>. i:.. Bone ::u#?. ?:+.; ,6...

,..4;:

... Calcified

cartilage

“\

A B c

D E F G

NOTE: From Roche, A. F.: The elongation of the

mandible. Am. J. Orthod. 53:79-94, 1967.

Figure 1. A diagram of the maturation of a long bone in which

the length of the bone has been kept constant. The approximate age scale is: A, 6 weeks prenatal; B, 7 weeks prenatal;

C, 12 weeks prenatal; D, 16 weeks prenatal to 2 years; E, 2 to

6 years; F, 6 to 16 years; and G, adulthood. The clear area in

D-G represents the marrow cavity.

3,
of endochondral and subperiosteal ossification

cannot bedistinguished radiographically.

The ossified areas extend along the cartilaginous model both centrally (endochondral) and on

its surface (subperiosteal) until they reach the

future epiphyseal zones (epiphyseo-diaphy seal

junctions) at each end of the model (figure 1-D).’

After this stage of maturation has been reached,

the ossified area is called the diaphysis or shaft

of the bone. Before this occurs, a marrow cavity

forms by resorption in the central part of the

ossified area. Marrow cavity information is not’

suitable for inclusion in a radiographic method of

skeletal age assessment. For a considerable period after the diaphysis reaches the epiphyseal

zones, the ossified area does not extend further,

relative to the total length of the bone, but radiographically visible changes occur in the shape of

the end of the diaphysis.

From the viewpoint of assessment, a most important stage of maturation occurs when epiphyseal centers of ossification form within the cartilage near the end of the diaphysis (figure l-E).

This occurs near each end of the diaphysis ot every

long bone and at one end of each short bone, e.g.,

metacarpal and phalanges. The ossified area in

each epiphyseal cartilage enlarges and, within a

few years, the cartilage is replaced completely,

except for that in contact with the end of the diaphysis and on the articular surface (figure 1-F).

At first, an epiphyseal ossification center enlarges rapidly in all directions. Later it enlarges

more rapidly in some directions than others, 11JJ7

and its shape gradually resembles that of the cartilaginous end of the bone$8 These changes in shape

are very important in assessment. The epiphyseal

ossification center enlarges by the apposition of

bone to each aspect except where the center is in

contact with the cartilage of the epiphyseal zone~g~zo

A transverse layer of cartilage remains between

the diaphysis and the ossified epiphysis after

bone has replaced most of the epiphyseal cartilage.

This transverse layer, together with the end of the

diaphysis, is important in diaphyseal elongation

and in the radiographic assessment of maturity.

The aspect of the epiphyseal ossification center in contact with the epiphyseal zone increases

in cross-sectional area more rapidly than either

the end of the diaphysis or the epiphyseal zone

cartilage. There is convincing evidence that the

increase in the cross-sectional area of the epiphy -

seal zone is due to the formation of new chondrocytes in the proliferative layer of the perichondrium and their subsequent migration into the

epiphyseal zone. 21’22’23

The increased cross-sectional area of this

zone is associated with increases in the crosssectional areas of the adjacent aspects of the

epiphysis and of the diaphysis (flaring). The relationships between these changes are used in

assessment?4’25

After an epiphyseal zone is present, the adjacent surfaces of the epiphyseal center and of the

diaphysis gradually become reciprocal in contour.

These changes are used to assess skeletal maturity. Later, the diaphyseal aspect of the epiphyseal

center is covered by a thin densely radio-opaque

layer of bone that is used as a maturity indicator.

As adult levels of maturity are approached, a thin

undulating layer of bone covers the end of the diaphysis separating it from the calcified cartilage

of the epiphyseal zone?6 This layer of bone and

the adjoining calcified cartilage together cause a

dense radio-opaque line that is used in assessment. The ridges that develop at the limits of

some muscular attachments cause radio-opaque

lines that are used in assessment, e.g., of the

distal portion of the ulnar diaphysis.27

The final phase of the maturation of a long

bone is bony fusion between the epiphysis and the

diaphysis. This is preceded by the formation of a

thick layer of calcified cartilage in the epiphyseal

zone. 28This calcified cartilage is replaced by bone

and, p’iogressively, the remaining epiphyseal zone

cartilage is calcified and replaced by bone. Ossification of the peripheral part of the epiphyseal

zone cartilage may remain incomplete for long

periods, causing a groove on the surface of a

bone that may be visible radiographically. After

bony fusion between the epiphysis and diaphysis is

complete, the articular cartilage is the sole remnant of the original cartilaginous model. The bone

has now attained adult maturity and further elon.

gation is not normally possible (figure l–G).

Many corresponding stages occur during the

maturation of the carpal bones that are in the

wrist between the forearm bones and the short

bones of the hand. A major difference is that the

carpal bones do not develop epiphyseal ossification

centers. Each carpal bone develops first as a con4
densation of embryonic connective tissue. Subsequently, cavitation occurs in this tissue in theregions of future joints between the carpal and

neighboring bones. After this occurs, the cartilaginous model, now resembling the future bone in

shape, articulates with its neighbors on some surfaces and is covered by a well-defined perichondrium on other surfaces (figures 2-A). Ossification begins in this cartilaginous model (figure 2- B,

2-C) with the same histological processes as

those described for endochondral ossification of

long bones. 29At first, the ossified area expands

rapidly in all directions;10 later growth is more

rapid in some directions than others (figure 2-D,

2-F).

Radiographic Changes

Knowledge of skeletal maturation increased

rapidly after radiographic techniques allowed serial studies of normal children. The early work of

Rotch,30 Bardeen,31 Pryor,32 and Hellman33 led to

the elaboration of the Todd34 and Greulich- Pyle

Z7135methods of assessment.

The radiologically visible changes used to

assess skeletal maturity are called “maturity

indicators;” skeletal maturity cannot be seen in

radiographs. By definition, these indicators appear in a fixed sequence for each bone, 27~36Y37

although the sequence is not fixed for an area, e.g.,

NOTE: From Roche, A. F.: The elongation of the mandible. Am. J. Orthod.

59:79-94.1967.

Figure 2. A diagram of the maturation of a carpal bone in which

total size has been kept constant. The approximate age scale

is: A, prenatal; B, 1-3 years; C, 4-5 years; D, 6 years; E, 10

years and F, adulthood.

hand-wrist that includes many bones$840 Each

indicator must appear during maturation in every

child to be useful in the assessment of skeletal

maturity. 37

The radiographic assessment of skeletal

maturity depends on the presence and relative radiodensity of areas of calcification or ossification.

These differences in radiodensity reflect the

three-dimensional shapes of radio-opaque calcified or ossified areas. Parts of the surfaces of

these areas (especially the dense cortex of bone)

that are approximately parallel to the radiographic

beam cause dense white zones on a radiograph.

The changes in contour during maturation, as

bones become more adult in shape, are important

in the radiographic assessment of maturity. These

changes reflect different rates of bone apposition

at various areas. Although the changes in shape

are associated with changes in size, the elements

of size used to assess maturity concern relative

size (shape), not absolute size. Use of absolute

size would lead to the unacceptable conclusion

that adults differ in maturity.

Scale of Maturity

The scale used in radiographic assessment is

based on the assumptions that skeletal maturity

is absent at conception, that all young adults are

completely mature, and that normally individuals

pass through the same sequence of maturity

stages. By these premises, each individual

achieves the same amount of maturation between

conception and adulthood, although the rates of

maturation differ among individuals. In practice,

the origin of the scale is the onset of ephiphyseal

or carpal ossification, as observed radiographi -

tally. Probably some radio-opaque epiphyseal or

carpal centers consist of calcified cartilage rather

than bone when assessors regard them as “ossified.” The only incontrovertible radiographic evidence that bone is present is the recognition of

trabeculae; these may not be visible for a considerable period after the center becomes radio-.

opaque. The end point of the skeletal maturity

scale is the completion of epiphyseal fusion in

bones that have epiphyses and the attainment of

final adult shape in carpal bones.

The skeletal maturity scales for individual

bones cannot be divided into units known to be

5
equivalent to each other. These ordinal scales do

not msusuw skeletal maturity but allow a maturation level to be assigned to a radiograph relative to standards. These standards represent the

central tendencies of skeletal maturity level in

healthy children and youths grouped bychronological age and sex. The levels (assessments)are

recorded in years or months ofskeletalage. Typically, girls achieve adult levels of skeletal maturity at younger chronological ages than do boys.

Consequently, girls must mature more than boys

during a “skeletal age year.” Furthermore, individual bones differ in the average chronological

ages at which they reach adult maturity levels.

Hence the percentage of adult maturity achieved

per skeletal age year must differ among bones.

It is not known whether a boy with a skeletal

age of 2 years is twice as mature as a boy with a

skeletal age of 1 year. Nevertheless, because all

boys mature until they reach the same adult level

of maturity, it follows that all boys at the same

skeletal maturity level (e.g., skeletal age, 9

years) have achieved the same percentage of

adult maturity, although the actual percentage

cannot be calculated because it is based on an

ordinal scale. By contrast, many physical characteristics of children, e.g., stature, are recorded using a cardinal scale. With such scales,

ratios between measures can be calculated, e.g.,

a boy weighing 70 kilograms is twice as heavy

as a boy weighing 35 kilograms. This advantage

of the cardinal scale is offset by the fact that

adults differ in weight and, therefore, one should

not infer that two boys each weighing 60 kilograms have achieved the same percentages of

their adult weights.

The scale used to assess the radiographs from

Cycles II and III is presented in the radiographic

standard of reference of Pyle et al.: referred to in

this report as the HES Standard. This scale was

derived principally from the Greulich-Pyle

Atlas~7 which contains reproductions of ordered

sets of radiographs for each sex. Each of these

radiographic standards is accompanied by skeletal

age equivalents in months or years for each bone

and for the whole hand-wrist area.=

aThe method by which the standard radiographs were selected is described by Greulich and Pyle 27and Pyle et al.8

THE USEFULNESS OF SKELETAL

MATURITY ASSESSMENTS

This topic will be outlined separately for

various professional groups despite the obvious

overlap between their needs and interests. National normative data are essential for each of

these groups.

Pediatricians. —There is increasing awareness of genetically determined syndromes in many

of which the rates and pattern of skeletal maturation. are abnormal. Skeletal age assessments are

necessary to define these syndromes better, to

assist tentative diagnosis, and to increase understanding of the temporal and topographic aspects

of the associated skeletal changes. They are significant also in relation to the more than 2 million

youths in the United States who are outside the 5th

to the 95th percentile range for stature. Commonly, there is concern on the part of youth and

parent about the deviant present stature of the

youth and the possibility that his mature stature

will be deviant also. This concern can be responsible for considerable adverse psychological effects, especially near the usual age of puberty,

when many short or tall youths become increasingly deviant in stature. The management of youths

with unusual statures should begin with assessments of present size and maturity and be directed

towards diagnosis.

Assessments of skeletal maturity are necessary in selecting children for therapy, more effective regulation of therapeutic agent dosage,

and more accurate estimates of therapeutic effects on potentials for growth in stature. Selection for therapy is particularly difficult when the

therapeutic agent is scarce, e.g., human growth

hormone. In this selection, not only diagnosis but

need must be considered; reliable estimates of

mature stature are necessary to identify those

children most in need from a physical viewpoint,

At many ages these estimates must be based on

the assessment of skeletal maturity$l To take

another example: an artificially induced pseudopuberty may be psychologically necessary in a

girl with Turner’s syndrome, although this treatment may reduce her potential for growth in stature. Clinical judgment is necessary in each individual case, and will remain necessary, to

decide when and whether to induce a pseudopuberty.

6
This judgment should depend, in part, on assessments of skeletal maturity to determine her present status and her potential for growth in stature.

The more reliably her mature stature could be

predicted, and if serial predictions are obtained

during therapy, the sounder would be the pediatrician’s judgment. These predictions depend upon

estimates of potentials for growth in stature and,

in turn, these estimates require assessments of

skeletal maturity. 42’43

Some short children are treated with “anabolic” steroids that have high anabolic-androgenic

ratios when the latter are measured by the current

unsatisfactory methods. The inadequacy of these

ratios to indicate therapeutic effectiveness has

been reviewed in detail.44 When such therapy is

used in attempts to increase the growth potentials

of short children, its effects on skeletal maturation

must be monitored carefully. Similar considerations apply to the regulation of dosage during

therapy with thyroxin and many other therapeutic

agents. Also skeletal maturation assessments

assist investigations of the determinants of skeletal morphology and the effects of drugs, hormones, malnutrition, and illness.

Pediatric surgeonsO--Asses sments of skeletal maturity provide significant help to orthopedists through their application to disassociations

bet!ween the rates of skeletal elongation and

skeletal maturation during pubescence, when

“catchup growth” occurs or when the blood supply

to all or part of the skeleton is abnormal, e.g.,

in congenital heart disease or in peripheral

arteriovenous anastomoses. The associations between the rates of skeletal maturation and skeletal

elongation are important in estimating the growthrelated ‘effects of cardiac surgery and in selecting

ages for this surgery. They are essential in selecting the sites and ages for surgical induction of

epiphyseal fusion in children with legs of unequal

length,

Speech thempists. —Some children who cannot achieve palatopharyngeal closure differ from

normal in cranial base flexion or in the lengths of

cranial base segments. The management of these

and other children can be improved by the intelligent use of assessments of skeletal maturity.

There is considerable evidence that growth potential in the cranial base is related to the maturity

of other parts of the skeleton. 45-50

Orthodontists and craniofacial surgeons. —

Orthodontic diagnosis and treatment depend, in

part, on the interpretation of metric data derived

from standardized cephalometric radiographs.

The relationships in normal children between

metric variables of direct concern to orthodontists and their changes across time should be

considered in relation to skeletal maturity status.

Assessments of skeletal maturity are important

also in determining whether pubertal spurts have

already occurred in the craniofacial area of an

individual and if not, the chronological ages at

which they are to be expected. The occurrence of

these spurts has been demonstrated recently. 50-53

Similar considerations apply to craniofacial surgery in individuals who are still growing.

Nutritionists.— Anthropometric data, e.g.,

stature, body weight, and subcutaneous fat thickness are used to recognize and grade malnutrition

and to assess the effectiveness of intervention

programs. Generally, it is considered that the effects of intervention are favorable if there is

c“atchup growth. 54-56 Usually these spurts (catchup growth)in anthropometric variables are considered in relation to chronological age. It would

be more meaningful to use biological age as a

time base, and the best available biological age

for this purpose is skeletal age. Alternative

clinical approaches have included the use of

multiple regression techniques to obtain a biological age from a combination of anthropometric

variables and skeletal age. 57,58 The wisdom of

this approach is doubtful, especially if an inadequate measure of skeletal maturity is employed. Catchup growth is favorable only if it is

not associated with excessive skeletal maturation and thus a reduction in the potential for

growth in stature.

Human biologists.— There is a need for

studies of associations between elongation and

maturation within and between bones. These associations are of real interest to human biologists

apart from their health- related significance. This

is clear from the abundant literature relating

separately to each, but there have been surprisingly few studies of their associations. Assessments of skeletal maturity are also of use as a

measure of biological age to classify data on biological and behavioral characteristics of children

in addition to the usual chronological age cate7
gories. Other aspects of concern to human biologists include genetic and environmental influences

on skeletal maturation rates and possible secular

changes in skeletal maturation levels. Proper

study of the latter topic requires data from

successive national probability samples. Much of

the reported data, relating to secular changes, is

difficult to interpret because of vagaries of sampling, the generally small group sizes, and differences in the methodology of assessment and

analysis.

THE HEALTH EXAMINATION

SURVEY STANDARD

As stated in the Introduction, a new radiographic standard for the assessment of skeletal

maturity of the hand-wrist was developed both for

the children’s survey and the present one of youths

by Drs. Greulich and Pyle in collaboration wi~h

Dr. Waterhouse at the request of and for specific

use in the U.S. National Health Examination Survey. This standard is based on the premises that

the process of growth implies maturation, that

there are marked individual differences in the

timing and rates of maturation but not its sequence, and that the rate of skeletal maturation

in the hand-wrist is an acceptable indicator, for

the purposes of this survey, of the overall rate

of skeletal maturation of a child or youth. The

standard further assumes that the transitional,

ossifying features and articular facets (maturity

indicators), identifiable on radiographs, are generally the same for both sexes and all races but

that the age intervals between which these features

develop are not uniform. It is well known that

maturation occurs more slowly in males than in

females who are on the same developmental

schedule relative to norms for their own sex.

The HES Standard for the hand-wrist has

been based on and in part abstracted from the

1959 GreuIich and Pyle Radiographic Atlas.z7 The

Atlas was in turn based principally on the research

radiographs and other data from the Brush

Foundation Study of Human Growth and Development of Cleveland, Ohio, which was organized in

1929 and directed for the first 10 years by Dr. T.

Wingate Todd. The Greulich and Pyle Atlas was

designed for direct skeletal age readings between

the ages of 3 months and 18 years. It includes

radiographic standards at intervals of 3 to approximately 12 months. Their spacing depends

upon the modal rate of maturation in the period.

The Atlas contains a series of standards (modal

radiographs) and skeletal ages for males and

another series for females.

Most of the radiographic plates used in preparing the HES Standard were selected from the

male hand-wrist series, pages 80-123, in the

Greulich-Pyle Atlas. 27With appropriate modification and supplementation, they provided a series

of typically occurring discernible features of

developing hand- wrist bones— a series spaced at

irregular age intervals from 3.8 months to 228

months of skeletal age. These features were related, as accurately as possible, to the chronological age levels at which they appeared in the

modal position for the Cleveland boys and girls

enrolled in the Brush study. To assign female

skeletal age equivalents to these male standards,

three sets of hand-wrist radiographs of girIs were

assessed using the HES Standard for the male

hand-wrist.

Although each plate in the published HES

Standard shows the skeletal age equivalents for

both males and females, those wh~ assessed the

national survey radiographs were not told the sex

or chronological age of the children or youths

whose radiographs were being assessed. The

skeletal ages assigned were based on the male

equivalents accompanying each standard plate. In

this report, the skeletal age data for girls are

shown both as assessed on the basis of the male

standards and after conversion by computer to the

corresponding skeletal ages for girls based on

equivalents in the manual. It was intended throughout this survey among youths, as in the previous

one among children, to obtain national estimates of

the comparative levels of skeletal maturation between the two sexes.

METHOD

At each of the 40 preselected locations

throughout the United States used consecutively in

this study, the youths were brought to the centrally

located mobile examination center for a standardize~ examination that lasted about 3%hours. Six

yojkhs were examined in the morning and six in

8
the afternoon. When each youth entered the examination center, his oral temperature was taken and

a screening for acute illness was made. If such

illness were detected, the youth was sent home and

reexamined later. Each examinee changed into

gymnasium-type shorts, cotton sweat socks, and a

robe; for girls only, also a light sleeveless topper.

Then all six proceeded to designated different

stations for the start of the examination. The examination was divided into six 35-minute time periods, each consisting of one or more detailed

examinations at a designated location, except for

the psychological component, which consisted of

two consecutive time periods (70 minutes). At the

end of each period the youths rotated to another

station so that during the 3Mhours each youth had

essentially the same examinations by the same

examiners but in a different sequence. Four of the

examination time periods were allocated to examinations by a pediatrician, a dentist, and a psychologist, and the other two were allocated to a group

of tests and examinations performed by highly

trained technicians. This last group of examinations consisted of radiographs of the. chest and

hand-wrist, hearing tests, measures of respiratory function, a 12-lead electrocardiogram, a submaximal exercise tolerance test on a treadmill

with chest leads to a continuous electrocardiogram, a battery of body measurements, determination of grip strength, examination of blood, and

a privately administered health behavior and attitude questionnaire, and on girls only urine cultures

for bacteria.

The time of each part of the examination was

recorded} but as in the children’s examination,

there is no reason to believe that diurnal or

sequence effects would be present in the composition or quality of the radiographic data.

Field Radiography

The methods used in field radiography were

identical to those in the preceding children’s program of examinations. Each youth was scheduled

to have a 10” X 12” radiograph of the right hand

and wrist, at a tube-film distance of 36 inches, for

which the positioning was otherwise in accordance

with specifications in the Greulich and Pyle

Atlas .27The tact that some radiographs were

made using other film sizes when the LO”X 12”

size was scarce would not have influenced the

findings. 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 entire hand-wrist with its full complement of ossifying parts at his examination age.

The decision to radiograph the right handwrist 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 selected

Greulich- Pyle Atlas standards 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 reported research by Roche59 on lateral

differences in the skeletal maturity of the handwrist, either for the area as a whole or bone by

bone, has shown that these are too small to be of

practical importance.

Training of Assessors

The assessment of skeletal age from the

hand-wrist radiographs of youths 12-17 years of

age in the Health Examination Survey of 1966-70

was made by nine medical students at Case Western Reserve University. These included five of the

six medical students who had done the assessments

in the 1963-65 national survey among children age

6-11 years.1 This work was also done under contract, with Dr. P. Wesley Dupertius as Project

Director, for the National Center for Health Statistics. Prior to their training under the meticulous supervision of Dr. Pyle, each assessor was

required to demonstrate his familiarity with the

series of maturity indicators of individual bones

in the hand-wrist, as described on pages 185-228

in the Greulich -Pyle Atlas .27

The practice procedures used in training

were based on 30 contact-size prints of handwrist radiographs used with the 1959_edition of the

Greulich-Pyle Atlas and a validating test based on

another set of prints of hand-wrist radiographs

with which the preliminary version of the HES

Standard (showing only the male standard skeletal

ages for each plate and each bone) was used.

9
During practice, each assessor first arranged

the 30 prints into what he considered the ascending skeletal maturity order. The bone-specific

skeletal ages for each print were assessed according to the male standards in the GreulichPyle Atlas and the corresponding skeletal age of

the hand-wrist for each print was determined by

averaging these skeletal ages. Next, the 30 prints

were rearranged according to these hand-wrist

skeletal ages and the new array was assessed according to the femule standards in the GreulichPyle Atlas. Then the first set of bone-specific

skeletal ages, based on the male standards, was

covered and a second set of bone-specific skeletal

age assessments was obtained using the male

standards for the second time. The first and

second sets of assessments were compared and

the assessor decided which he considered the

better final rating for each print. These ratings

were reviewed to determine whether the assessor

needed additional practice and training before

proceeding to the next phase. When the project

director considered the assessments sufficiently

reliable, the assessor was given the validating

test in which his assessments, and the extent of

variability in his independent reassessments,

were compared with those of Dr. Pyle. When the

ratings and reliability for the new assessor were

in good agreement with those of Dr. Pyle—the

majority of differences were within 4 months—the

new assessor began his assessrnnent of the survey

radiographs. Reported evidence suggests that, at

the end of this training procedure, the interobserver and the intraobserver differences in skeletal maturity ratings should have been similar to

those for experienced assessors.

Assessment Procedure

The radiographs from the survey examination

were assessed by comparison with prints of the

series of standards for the male hand-wrist selected from those in the Greulich- Pyle Atlas27 and

other sources which have been reversed so they

appear to be of the right hand-wrist as shown in

the Radioqaphic Standavd of Reference of Pyle

et al.s This standard contains the male skeletal age

equivalents that were used during the assessment

of radiographs for children and youths in Cycle H

(6-11 years) and Cycle III (12-17 years), with some

very siight modification to smooth the skeletal age

trend for a few bones.

In making the assessments the readers did

not have access to the chronological age, sex, or

any other information about the youth. ‘Theassessor rated each bone separately and interpolated

between the standards to monthly intervals when

this appeared appropriate.

As a quality control measure and to permit

determination of the level of reliability of the

assessments throughout this study, independent

replicates were obtained on approximately one 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. The time lapse between

the first and the reassessment was sufficiently

long that there was little likelihood of recall,

Furthermore, there was no indication to the assessor that he was making a reassessment. Information on the degree of reliability of these

assessments is contained in appendix II.

In skeletal age assessments using reference

standards, there are limits to the range of skeletal

ages that can be applied to each bone. The limits

that were applied in the survey are in table A. For

example, a trapezoid is not visible until Plate 12

of the HES Standard, where the hand-wrist skeletal age (male) is equivalent to 72 months and the

trapezoid shadow measures about 4.5 x 4.0 mm.;

the trapezoid would be smaller than this when

first radio-opaque. Thus it is reasonable to assign

an age slightly less than 72 months to some radiographs. However, the assigned skeletal age must

exceed 60 months because at that level (Plate 11)

the trapezoid is not radio-opaque. Lower limits for

these assessments were arbitrarily set for each

bone that was midway in skeletal age between the

last standard in which the particular bone was not

radio-opaque and the first in which it was radioopaque. Three exceptions were made: the minimum ages for the pisiform and the adductor and

flexor sesamoids were placed 2 months above the

levels of last plates in which these bones were not

radio-opaque. These exceptions were made because the limits were set CZJ%Wthe assessments

had been made and, for many radiographs, the

10
Table A. Minimum and maximum acceptable skeletal ages in months “ the HES male

standards: Health Exam?~~~on Survey, 1966-

70

Hand-wrist bone

Radius ----------------------

Ulna ------------------------

Cavitate --------------------

Hamate ----------------------

TrLquetral ------------------

Lunate ----------------------

Scaphoid --------------------

Trapezium-------------------

Trapezoid -------------------

Metacarpal I----------------

Metacarpal II----------------

Metacarpal III--------------

Metacarpal IV---------------

Metacarpal V----------------

Proximal Phalanx I----------

Prox~mal Phalanx II-v -------

Middle Phalanx II-IV --------

Middle Phalanx V------------

Distal Phalanx I------------

D3-stal Phalanx II, V--------

Distal Phalanx III----------

Distal Phalanx IV-----------

Pi.siform --------------------

Adductor sesarnoid -----------

Flexor sesamoid -------------

Skeletal age

in months

15

70

---

---

17

35

;!

68

H

:;

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

lMhti.mum age (according to standard) of

radio-opacity of epiphysis or carpal.

‘1 month below “adult” age.

assigned ages for these three bones were slightly

lower than the’ ‘midway’’ limits.

There prelimits also at the upper end of the

range,when bones becomeadult. Onlythedesignation ’’adult,” andnota skeletal ageinmonths, can

be assigned to aboneinwhichmaturation is complete. The median ages from thefIES Standardat

which this occurs in boys were used to calculate

the skeletal ages in months for each bone beyond

which only the designation “adult” canbe applied.

Because the assessments were made to l-month

intervals, the maximum value for eachbonewasl

month below its adult value. The maximum values

1 month below these “adult” skeletal ages are

shown in tableA.

It should be noted that the limits in tableA

refer to male skeletal ages only, because these

were assigned to all the survey radiographs, irrespective of sex. The assessors didnotknowthe

sexoftheyouths. As expected, withinchronological age groups, the skeletal ages assigned to the

girls were more advanced than those assignedto

the boys. This occurs because, although boysand

girls pass through essentially the same skeletal

maturitystages ,girlstend to mature more rapidly than boys. The female equivalent skeletalages,

bone by bone, corresponding to the male skeletal

ages were determined during the preparationof

the HESStandard butwere notused inassessment

of the survey radiographs. Tbemethod by which

these female equivalent skeletal ages were obtained is described indetail in Pyle etal.8These

ages were estimated using three sets of serial

radiographs of normal United States girls. The

modal radiograph (in maturity)foreachchronological age group in each set was assessed against

the female standards inthe Greulich-Pyle Atlas27

and against the HES Standard (male). These sequential female equivalent skeletal ageswerethen

smoothed.

The skeletal age data for girls in this report

are presented both in terms of the male age

equivalents as assigned andalso in terms offemale equivalent skeletalages. Theconversionwas

done by computer, bone by bone, using theequivalency data in the HES Standard with interpolation

between the published valuestomonthly intervals.

The skeletal ages for the hand-wrist area asa

whole, for boys and girls, were determined by

averaging the ages assigned to each ossifying

hand-wrist bone for each youth.

FINDINGS

Skeletal Age (Hand-Wrist)

The trend and extent ofvariationinthe timing

and velocity of skeletal maturation among United

States boys and girls age 6-11 years, as measured

11
by the J3ES Standard for the hand-wrist using the

Greulich-P yle method, have been described and

analyzed.1 Those national estimates are based on

findings from the Health Examination Survey in

1963-65 among a national probability sample representative of noninstitutionalized children in

this country. The scale used, both in that report

and the present one, is based on the assumption

that skeletal maturity is absent at conception and

that all individuals reach the same level of complete maturity in young adulthood. Those bones

that have reached complete maturity or the “adult”

stage—epiphyseal fusion completed in bones that

have epiphyses or final adult shape in the carpals—

are excluded in determining skeletal age. Among

those of 6-11 years, none of the boys and less than

1 percent of the girls had any “adult f‘ hand-wrist

bones.

National estimates for skeletal age (handwrist) of youths 12-17 years, based on findings

from the Health Examination Survey of 1966-70

among the national probability sample representative of civilian noninstitutionalized youths, are

limited to those who have at least 1 of the 31 handwrist bones still maturing ( i.e., not yet “adult”).

The proportion of boys consequently excluded in

this determination because all 31 bones had reached adult maturity increases from zero at ages

12-14 years to 10 percent at age 17 years. Among

girls, the proportion excluded increases from zero

at age 12 years to 22 percent at age 17 years. As

a result, at age 17 the skeletal age comparisons in

this report are based on ,almost all the boys (90

percent) but only about three-fourths (78 percent)

of the girls—the less rapidly maturing.

Due to the difficulty of accurately assessing

skeletal age within the 6 months preceding the

final adult stage, the readers arbitrarily assigned

values of “A-6” to those bones that were considered to be within 6 months of the adult stage. In

boys it can be assumed that such a bone would

have become adult within the next 6 calendar

months; in girls the corresponding changes would

have required no more than 5 calendar months because girls mature more rapidly than boys. This

sex-associated difference in maturation rates was

taken into account when transforming the male

values assigned to the girls to female equivalent

values. However, the use of the designation

for the entire last 6-month interval results

12

A-6

in a

+’30

r

.,o~ 6789 10 11 12 13 14 16 18

cHRONOLOGICAL AGE IN YEARS

Fiaure 3. Mean difference in months between skeletal aqe

~hand-wrist) and chronological ages of boys and girls agair&

the male standard and female equivalent values for girls, by

chronological age in years for ages6-17 years: United States,

1963-70.

slight but increasing underestimate in the skeletal

ages for older youths as they approach skeletal

maturity. The extent of underestimation will

necessarily be slightly greater among girls when

assessed against the male standard than among

boys hut will be less than 2 months, on the average,

even at 17 years of age for girls, where the effect

will be at a maximum.

The mean skeletal age (hand-wrist) of boys

in the United States increases 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 150months)

to 17.1 years (205.4 months) at chronological age

17 years (mean chronological age 17.5 years or

210 months) (table 1 and figure 3). The yearly increment in skeletal age is greatest among the

younger boys age 12-13 years, when it reaches a

maximum of 17 months, or just slightly greater

than at 11-12 years and 13-14 years (where the increments were 16 months), then decreases to 10

and 9 months at ages 16 and 17 years or to about
the same level of increment as that found in the

1963-65 national survey among boys 6-11 years

old.

The lag of mean skeletal age (hand-wrist) behind chronological age for boys which had increased from 2.5 months at age 6 years to 13.8

months at age 11 years (from the 1963-65 national survey) drops from that peak to 9.8 months at

age 12 years and continues decreasing to become

less than 1 month behind at 14 years and 0.5

month in advance of chronological age at 15 years.

At 16 and 17 years the mean skeletal age of boys

again lags behind their chronological age by 1.6

and 4.6 months, respectively (figure 3). The

apparent lag in skeletal age among older boys may,

at least in part, be an artifact of the method used

for this determination. By excluding bones that

are mature (adult), a smaller base remains for

the determination of skeletal age (hand-wrist).

Furthermore, as mentioned earlier, boys were excluded if all the hand-wrist bones were adult.

Among boys, the mean number of bones that are

still maturing (not yet adult) decreases consistently from 29 at ages 12 and 13 years to 6 at age 17

years (table 5 and figures 4 and 5).

Among girls, when assessment is made

against the HES Standard for males by readers

not knowing the sex of the youth, the mean skeletal

age (hand-wrist) increases from 14.6 years (174.9

months) at chronological age 12 years (mean 12.5

years or 150 months) to 17.6 years (211.3 and

30 –

. . . ...”

Girls . .. ...

/

...””

,.+”

20 /.’”

/

...

/

;.””

10 ;:

~.

...

~.”

o I I \ I

678910 11 12 13 14 15 16 17 16

CHRONOLOGICAL AGE IN YEARS

Figure 4. Mean number of adult bones in the hand-wrist of

children end youths eqes 6-17 Years by chronological age in

years and sex:”United States, 1963-70.

30

n

. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . ...

%.

%+

...

...

..+

20 ...

...

%

... Boys

%.

Girls ..

10 ~.+

...

%.

%...

%.

.. . . . . . .

o~

67691011 12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Figure 5. Mean number of ossifying (not yet adult) bones in the

hand-wrist of children and youths ages6-17 years by chronological age in years and sex: United States, 1963-70.

211.5 months) at ages 16 and 17 years (wlien the

means for chronological ages were 16.5 years or

198 months and 17.5 years or 210 months, respe~tively). The yearly increment in skeletal age

for girls in the age span 12-17 years is consistently less than that for boys, in contrast to findings among children 8-12 years. For girls it is

maximal between 10 and 11 years (18.8 months)

from the 1963-65 national survey and then steadily

decreases to less than 1 month between 16 and 17

years. This decrease in yearly increments is

largely artifactual due to the exclusion of handwrist bones that had become adult in the older

girls. The skeletal age ratings against the male

standard consistently exceed the chronological age

of U.S. girls by mean values ranging from less than

2 months at age 17 to 24-25 months at 12-14 years.

After transformation to female equivalent

skeletal ages as described in the Methods section, the mean skeletal age (hand-wrist) of U.S.

girls increases with chronological age from 11.9

years (142.9 months) at age 12 years (mean 12.5

years or 150 months) to 15.5 years (185.6 and

186.0 months) at chronological ages 16 and 17

years, respectively. The lag of skeletal age (female equivalent values) behind chronological age

for girls of age 12 years is slightly less than the

maximum value for the female children which

occurred at age 11 years in the 1963-65 national

survey (7. 1 months at age 12 years compared with

9.8 months at age 11 years) and decreases slightly

13
to a minimum of 6.0 months at age 14 years.

From age 15 years on, the lag ofskeletalage behind chronologicalage becomes progressively

greater, reaching a maximum value of 24 months at

chronological age .17 years, in sharp contrast to

the findings for boys.

These deviant findings among older girls reflect the substantial exclusion of the bones in

which skeletal maturation was more rapid. The

mean number of bones on which skeletal age determinations were made for U.S. girls decreased

from 26 bones at age 12 years to 5.9, 3.6, and 3.4

bones at ages 15, 16, and 17 years, respectively.

As a result, the estimates for the hand-wrist

skeletal age for the older girls would be less reliable than for younger girls and are based on

bones last to become adult. In addition, nearly 22

percent of the 17-year-old girls were excluded

from the group for whom skeletal age (hand-wrist)

was determined because all 31 hand-wrist bones

in these girls were rated as adult.

The extent to which the mean hand-wrist

skeletal ages for youths 12-17 years of age have

been affected by the exclusion of youths in whom

all the hand- wrist bones have reached adult levels

of maturity can be estimated if it is.assumed that

the maximum adult skeletal age is equivalent to

about 19.1years or 229 months (male adultvalue

for the radius,which isthelasthand-wristbone

to become adult). This valuewas chosenarbitrarily to maximize the skeletal age of the hand-wrist

in each excluded youth. The effects of these adjustments (table B) would be to increase the mean

skeletal age (hand- wrist) for all 17- year-old boys

by 2.5 months and to reduce the lag behind their

mean chronological age from 4.6to 2.1months.

For girls the adjustment would be negligible until

age 17 years, when skeletal age (hand-wrist), as

determined from the male standard, would be increased by 3.8 months and the female equivalent

values would be increased by 2.7 months. At age

17 this would leave the mean skeletal age (handwrist) for girls on the male standard nearly half

a year (5.3 months), on the average, in advance of

their chronological age (rather than 1.5 months)

and would reduce the mean lag of the female

equivalent value behind the chronological age

from 24.0 months to 21.3 months. lt is stressed

that these adjustments were not actually made for

any of the datu in this vepo?’t. The data in table B

illustrate, however, the maximum effect that could

have resulted from the exclusion of youths in whom

all the hand-wrist bones were adult.

An alternative procedure was considered but

was not adopted. The median of all bone-specific

skeletal ages could have been used instead of the

mean—this value would have been less affected

than the mean by the exclusion of values for bones

Table B. Mean skeletal age (hand-wrist) of youths age 12-17 years as determined from

those youths with some bones still maturing and also as determined from the “total

sample“ of youths : United States, 1966-70

Chronological age

at last birthday

12 years --------------

13 years --------------

14 years --------------

15 years --------------

16 years --------------

17 years --------------

Girls (male

standard)

Girls (female

equivalent)

So~i:~nes ‘rotal

maturing samplel

Mean skeletal age (hand-wrist) in months

140.2 140.2 174.9 174.9 142.9 142.9

157.4 157.4 186.6 186.7 155.2 155,3

173,6 173.6 198.0 198.1 168.0 168.1

186.5 186.6 205.6 205.9 177.6 177.8

196.4 196.7 211.3 211.9 185.6 186.1

205.4 207.9 211.5 215.3 186.0 188.7

lThe “total sample“ includes youths with all 31 h,and-wrist bones rated as adult. For

these youths, a skeletal age of 229 months on the male standard and of 207 for the female equivalent has been assigned.

14
that had become adult. This procedure was not

used because it implies that all “adult” bones are

at the upper end of the scale in skeletal age months

(which is not true for some bones, e.g., distal

phalanges) and it would have introduced inconsistencies between the present method of analysis

and that applied earlier to the data from children.1

In contrast to the findings among 6-11 year

old children, the lag of skeletal age behind chronological age diminishes with chronological age from

12-14 years, markedly for boys and very slightly

for girls (female equivalent values for the latter).

When the data for the girls assessed against the

male standards are considered, there is scarcely

any change in the extent of their advancement of

skeletal age over chronological age during the

12-14 year age span (i.e., points plotted at 12.5-

14.5 years in figure 3). After age 14, the mean

skeletal- chronological age differences for the

boys decrease slightly until 15 years and then increase so that at 17 years the mean skeletal age

is about 5 months less than the chronological age.

When the girls are assessed against the male

standards, the mean skeletal ages exceed the

chronological ages but by an amount that decreases

sharply after 14 years to a difference of only about

1 month at 17 years. However, when the female

equivalent values are considered, there is a sharp

increase in the mean amounts by which the skeletal

ages are less than the corresponding chronological

ages. This occurs, in part, because the malefemale differences that were used to transform the

data for girls to female equivalent values are

essentially constant across age after 15 years.

Put another way, among these older girls, the

mean hand- wrist skeletal ages (female equivalent

values) become increasingly lower than chronological age as chronological age increases. For

girIs 15-17 years old, the rate of change in the

difference between skeletal and chronological age,

with chronological age, is substantially greater

than during childhood (6- 11 years).

The sex-associated differences in skeletal

maturity are shown more clearly by the mean differences between the skeletaI ages assigned to the

boys and to the girls when all are assessed against

the same set of male standards. These differences (in months of skeletal age, male) are about

32 months at 11 years and 35 months at 12 years.

As later ages are considered, these mean differences decrease progressively until 17 years, when

the difference is about 6 months.

The mean hand- wrist skeletal ages of girls,

after transformation to female equivalent values,

are about 3 months more advanced than those of

boys at age 12 years, continuing the trend present

among children 10 and 11 years old.1 However,

from age 13 years on the mean values for boys

become increasingly greater than those for girls

by values ranging from 2 months at 13 years to

over 19 months at age 17 years.

To illustrate these sex differences better figure 6 is presented as a transformation of figure 3.

In figure 6 the male skeletal age values have been

placed at the zero line by making the mean skeletal ages for the maIes equal to their mean chronological ages. Consequently, both sets of female

values in this figure (those read on the male

scale and those based on female equivalent values)

represent, at any age, the mean difference from

+40 ~

..............

....

...

0 -

. ............. .. ...

.,.

...

%.

%,.

...

....

....

-10 _ — Both Sexes-Male Standard %...

. . . . . Boy,. Male Standard,

...

Girls. Female Equivalent ..

%.

%..

%.

-20- I I I I I I I I I I I .

I

6789 10 11 12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Figure 6. Mean differences in skeletal age (hand-wrist) between

boys and girls based on (1) determinations against the male

standard for both sexes and (2) after conversion to female

equivalent values for the girls at chronological ages 6-17

years: United States, 1963-70.

15
themale values. Asaresult ofthistransformation,

the pubertal spurt of skeletal maturation in the

girls is shown moreclearly. The female equivalent

values are close, to zero from 6 to 13 years,

showing that the transformation from the values

obtained by assessments against the male standards was appropriate. It can be seen also that the

female equivalent values fall below zero at about

13 years, indicating that at later ages the “standards” are set too high or the sex differences that

were applied were too large. Gf course, the national survey data would allow a more exact transformation to make the female equivalent values

equal to zero in figure 6 (mean chronological age

equal to mean skeletal age). This has not been

done.

When the rate of skeletal maturation of youths

is considered over 6-monthly rather than yearly

chronological age intervals, the trend is similar

but slightly less consistent (table 1 and figure 7).

Mean half-year increments range from a maxi-

+30 r

t

-..

— Boys-Male Standard

-20 ‘-- Gkls-Male Standard

.. . . . . Girls-Female Equivalent :

...

...

.,, ~

6769 10 11 12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEAR3

Figure 7. Mean difference in months between skeletal age

(hand-wrist) and chronological age of boys and girls against

the male standard and female equivalent values for girls at 6

months of chronological age for ages 6-17 years: United

Statesr 1963-70.

mum of 11 months (skeletal age) for boys during

their 13th year (12 to 13) to a minimum of 2

months during their 18th year (17 to 18) of chronological age. The 6-month increments for girls,

either on the male standards or using female

equivalent values, are similar to the findings at

yearly age intervals. Generally, they are less

than those for boys and are slightly greater

among younger (12 and 13 years) than older (16

and 17 years) girls (5-7 months compared with 2

months or less).

The mean skeletal ages for both boys and

girls show a similar but less consistent decreasing trend when considered in single-month intervals of chronological age (table 2). This would be

expected because the sample is too small to provide reliable estimates within these brief age intervals.

Variability in skeletal age (hand-wrist) has

been compared using the standard deviations.

These are substantially greater among boys 12-16

years of age than among those 6-11 years of age

from the 1963-65 national survey. When calculated for annual intervals, the standard deviations

range from a maximum of. 18 months at age 13

years to a minimum of 11 months at 17 years. An

increase in variability in boys became evident at

age 11 years in the earlier study of children, when

the standard deviation increased from nearly 10

months at age 10 years to more than 12 months at

age 11. By age 12 and 13 years the standard deviation increases to 17 and 18 months, respectively,

but later decreases gradually to a level similar to

that -found among children (11 months).

Among girls the maximum variability during

the entire age span 6-17 years, as measured by

the standard deviation, is reached at age 10 years,

both for skeletal age recorded on the male standard and for the transformed female equivalent

values. The level of variability at age 12 years

(nearly 15 months on the male standard values)

is similar to that at 11 years but then decreases

to a minimum (for the entire age range 6-17 years)

of about 9 months at 15 years and remains just

slightly above this level at 16 and 17 years (table 1).

The relative variability in relation to the mean

was measured by the coefficient of variation (100

times the standard deviation divided by the mean),

which was calculated for each annual interval. In

16
I

Girls

o~6789 10 11 12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Ficmre 8. Relative variability in skeletal aae (hand-wrist) bv

chronological age in years ‘for boys and g;rls ages 6-17 yea&

United States, 1963-70.

boys, after reaching a minimum value (less than 9)

at age 10 years, these coefficients increase to a

maximum of 12 at 12 years of age and then steadily decrease to the minimum value of 5 at age 17

years., For girls, when assessed against the same

male standards, these coefficients decrease

steadily from nearly 12 at 10 years of age to

about 5 at 15-17 years (figure 8). Boys are consistently more variable than girls throughout the

age range 12-17 years. Considering the combined

age ranges (6- 17 years) of the previous survey of

children and the present one of youth, the findings

show that boys are more variable in skeletal age

than girls at all ages except at 9 and 10 years.

The patterns of change are essentially the same

in each sex, but the alterations occur about 2

years earlier in the girls. This would indicate

that the relative variability is the same for each

sex at the same actual stage of maturation.

The distribution of skeletal ages within each

chronological year of age tends to be fairly

symmetrical and close to normal among younger

boys and girls 12-14 years of age (tables 3 and 4

and figure 9). At no point, over the 12-17 year age

range, do the mean and median values in the distributions of skeletal ages for boys or girls differ

by more than 3 months, which is similar to the

findings among children 6-11 years in the 1963-65

national survey. Among the older girls, particu -

larly, and to a lesser extent among the older boys,

the distributions become progressively more

skewed to the right (toward the maximum values)

as more of the youths approach skeletal maturity.

The greater effect in the girls reflects the fact

that their skeletons are maturing more rapidly

than those of boys.

Previous ~epovted data for youths in the United

Stutes.--Comparison with findings from previous

investigations has been restricted to those studies

that included at least 25 boys or 25 girls at each

annual age interval. Many of these studies have

been described earlier in the report concerning

children;l in this account there are some changes

in sample size and birth dates because of the different age range to which reference is made. In

some of these investigations radiographs were

taken of the right hand-wrist but the possible

small lateral differences in skeletal maturity

have been disregarded in this review.

Mean level,— To facilitate comparisons, the

data reported by various investigators have been

adjusted to a common Greulich-Pyle baseline (figures 10- 13). To achieve this adjustment, the

standard plates of Flory61 and Todd34 have been

assessed using the Greulich-Pyle Atlas27 to assign

bone- specific ages, interpolating when this appeared desirable. This is a rather unsatisfactory

procedure towards 17 years (chronological age)

when many bones have become adult and the reliability of assessments is necessarily reduced. In

addition, some plates in the Flory Atlas are reproduced so indistinctly that the carpals cannot be

assessed. The maturity levels assigned to the

Flory and Todd plates, in common with the Greulich and Pyle standards, are modal values rather

than means. Most investigators have reported

means and standard deviations for skeletal age

within chronological age groups, 27$2-64 but Maresh65 reported medians.

The Greulich and Pyle skeletal maturity

standards were selected from radiographs of

white youths of upper socioeconomic status living

in Cleveland. These youths were born between

1917 and 1942 and were radiographed close to

their birtl,: ’17s and half birthdays. The method by

which the stanaard plates were selected, from the

100 radiographs available for each sex at each

age, is described in detail in the Atlas of Greulich

and Pyle .27

17
+30 r

BOYS

,/ /“””\\

+20

/

\

\

Percentile

.--,

,/’

\

g \

\

\ /

\

g

\ .....

\ 95th ..

0

+1 o

\\

~

/ ,.. . .

\

/

.. . . . . . .... ●.,

w

w

●..

< .. . . . . . . . . . . . .

XJ /+’ $.

A

%,

~

..4 /’

...

%, #“ 75th

G o —

... ~“

Cj .- .-~

. -+

... ~’

0

./ \.

“---.+

%.

z t

..”” ,/ \ Lj~

~ %..........” I

~

‘\* ~’

i “~ +

‘\ /~

25th

‘\v/.

.

‘.. ,,f -----

Y

,,,, Z 5th

.

k..z-- ,,*’ -. ‘

8

~ --

.30 —

~’

c

. . . . . . . . .

u! “.=

{’

k

%=

,

E

-.

-. ;$’

-.

-..1+

.40

t

.. ,~

13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

+30

r

GIRLS

.506~

10 11 12 13 14 15 16 17 18

CHRONOLOGICAL AGE IN YEARS

Figure 9. Selected percentiles in the distribution of differences between skeletal (hand-wrist) and chronological age 6-17 years for

boys and girls (female equivalent values for the latter) by chronological age in years: United States, 1963-70.

The system of assessing skeletal maturity by

comparing radiographs with standards was introduced soon after the development of radiography.

Early workers to publish sets of standards

included Wilms66 and Woodrow.67 Howard68 published standards selected from radiographs of

Atlanta public school youths born between 1912

and 1916. These standards were chosen from

samples of 50 radiographs for each annual interval in each sex. The maturity levels of these standards, for the age range 12-14 years, are about 2

years below those of the Greulich- Pyle standards.

The data have not been included in figures 10 and 12

because neither the ethnic origin nor socioeconomic status of the sample was reported. Furthermore, the sample was too small for a reliable

selection of standards, particularly considering

that these radiographs were taken at random

chronological ages.

A mixed longitudinal study of white Chicago

youths of above average socioeconomic status born

between 1904 and 1917 was reported by Flory. 61

Radiographs taken within 2 weeks of a birthday

were available for 100 youths of each sex at each

age. The plates selected by Flory as best representing the central tendencies in his groups are

about one skeletal age year below the corresponding Greulich- Pyle standards for each sex. This

difference tends to fluctuate with chronological

age in both boys and girls without showing a regular trend (figures 10 and 12).

Dearborn and Rothney69 reported mean handwrist skeletal ages of 233 boys and 371 girls who

had been examined annually. These youths were

.

18
+0.5—

0,0 –

.0.5–

.1.0–

---- ,~”

+1.0 r

GIRLs

g

<

g +0.5

i3

<

:J

.......

......

/.

: ...

....

E

~

o

0

z

0

K

g

% .0.5

Y

w

-- FIoIY (1936)61

2

-...simmons (1944)62

—Todd (1937]34

~

w -1.0

iii g /

‘\ \\ ,/’ \/

-1.5 1 I I I I i

12 13 14 15 16 17 18

Figure 10. Differences between skeletel and chronological ages

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

(1944), and Todd (1937).

Figure 12. Differences between skeletal and chronological ages

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

(1944), and Todd (1937).

BOYS

+1.0

1

-- FIY(1966)6~

.. . .. . Maresh(1970)65

. . . . Johnston(1962]6~

..- Greulichand Pyle (1959)’27

— UnitedStates, 1966-70

----

+0.6 ----

----

< ----

‘N.

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

~.-.-

\

. . . . . . . . . . . 0. .-.

,1.0 ~

14 15 16 17 18

Figure 11. Differences between skeletal and chronological ages

of boys 12-17 years in studies of Fry (1966), Maresh (1971),

Johnston (1962), Greulich-Pvle (1959) and United States

youths (1 966-70):

slightly above average in socioeconomic status

and were living in or near Boston. They were

mainly of North European or Italian ethnic origin

and had been born about 1917. The skeletal age

assessments were made using unpublished Todd

CHRONOLOGICAL AGE IN YEARS

,,,.............................

.--74=---

.,,.- \,

N. ?...

\ ““...

j ‘\ ““”...

‘\ ““...

-.. 4

‘\ ‘%.

-- __+”..: : ‘\ “..

/....., + .. .. ; ....

..O ~: :

...”” %<

.. .. j

..:t

---FrY (1968)64

. . . . .. Mar=h (,g,o)65

.---. Johnston{1982)63

--- GreulichandPyle (1959)27

— United States,1966-70

CHRONOLOGICAL AGE IN YEARS

Figure 13. Differences between skeletel and chronological ages

of girls 12-17 years in studies of Fry (1966), Maresh (1971),

Johnston (1962), Greulich-Pyle (1959) and United States

youths (1966-70).

19
standards. Consequently, it is impossible to transform, with reasonable reliability, the reported data

to the common Greulich-P yle base line that is

being used to compare the findings from different

studies. For this reason, these reported data

have not been included in figures 10-13.

Simmonsb2 reported mixed longitudinal data

from Cleveland youths of above average socioeconomic status who were born between 1917 and

1940 and examined on or near their birthdays.

The number of radiographs assessed for each

year of age varied from 68 to 198 in each sex except for girls aged 15 years or more. Radiographs

of older girls were not assessed if they had

“surpassed the upper limits for the standards.”

Consequently, the data of Simmons are highly

selected for older girls and they have been omitted

from figure 12 for chronological ages after 14

years. After adjustment to compensate for the use

of the Todd Atlas, all the mean skeletal ages reported by Simmons are within 0.5 year (skeletal

age) of the Greulich- Pyle standards except at 14

and 15 years in boys, when the differences are

slightly larger. This close correspondence is not

surprising because the radiographs used by Simmons formed part of the group used by Greulich

and Pyle. The means of Simmons are lower than

those of Greulich and Pyle except at 17 years in

boys and 12-14 years in girls.

Todd’s Atlas34 was based on radiographs of

Cleveland youths, “from all grades of society,

except the destitute,” who were born between 1915

and 1936 and examined serially near each birthday or half birthday. The standard plates were

selected from groups of 42 to 161 youths of each

sex, for each 6 months of age. The “median”

levels of the Todd Atlas are about 0.5 year (skeletal age) lower than the Greulich-P yle standards

at most ages in both boys and girls, (figure 10 and

12) except towards the end of the 12-17 year range,

when they are slightly higher than the GreulichPyle standards. Expectedly, the maturity levels of

Todd34 are lower than those of Simmons$2 but the

means from the two studies are remarkably

parallel across age in each sex. Although there

was some overlap between the groups of radiographs used by these two investigators, Simmons

used only those of youths of high socioeconomic

status and Todd used radiographs of youths from

almost all socioeconomic levels.

Mixed longitudinal data from the Harvard

Growth Study were reported by Greulich and

Pyle?7 These radiographs were of white middle

class Boston youths who were born between 1930

and 1939 and examined near each birthday. The

size of the group varied from 60 to 65 at each age

in each sex. Data for girls were not included after 15 years because, in a majority of the girls

at these ages, most of the hand-wrist bones were

adult in maturity. All the mean skeletal ages were

within 0.4 year of the corresponding GreulichPyle standards, with a slight tendency to advancement that was more marked in the girls than the

boys.

Johnstonb3 reported mixed longitudinal data

from middle and upper middle class Philadelphia

white youths who were ban between 1931 and 1950.

The size of the group varied from 23 to 50 for

each amual interval in each sex. The only exception was at 17 years, when the group was

much smaller in each sex (10 boys, 13 girls).

Consequently, the means reported for youths age

17 years have been omitted from figures 11 and

13. The radiographic examinations were made at

random chronological ages; the data relating to,

for example, “9 years chronological age,” were

derived from youths ranging in age from 8.5 to

9.49 years. The mean skeletal ages for each sex

were advanced, relative to the Greulich- Pyle

standards, by 0.3 to 0.6 year within chronological

age groups.

Skeletal age data from middle class white

youths, in Nebraska, born between 1952 and 1954

and examined cross- sectionally at random ages

between 12 and 14 years, have been reported by

Fry’4* The group for each annual interval included

25 boys and 25 girls. Many of these youths (65 percent) were twins so more than half of these would

have been like-sexed. The mean skeletal ages for

the boys were below the Greulich- Pyle standards

by amounts that varied between 0.2 and 0.6 skeletal

age year. The mean skeletal ages for the girls

were above the Greulich-Pyle standards by 0.1 to

0.2 years (figures 11 and 13). The mean levels for

the two sexes tended to diverge with advancing

age—presumably variability among the various

age groups were largely responsible for this.

Maresh reported mixed longitudinal data

from middle class white youths living in Denver.

These data were obtained from radiographs taken

20
close to birthdays and half birthdays. Although

these youths were born between 1915 and 1955,

most of the radiographs were taken after 1947.

The size of the groups varied from 21t043 for

each 6-month age interval from 12 to 17 years in

each sex, with the exception of 15.5 and 16.5 years

in the girls when the group was smaller$5 The

median skeletal ages for the boys were 0.3 to 1.1

years below the Greulich-P yle standards during

the age range 12-17 years. During this same age

range the medians for the girls were generally below the Greulich-Pyle standards but differed from

them by no more than 0.6 year.

Figures 10 and 11 show differences between

modal skeletal ages and chronological ages for

these several groups of boys and for boys included

in the national survey. When converted to a common Greulich- Pyle baseline, the atlas standards

of Flory and Todd are retarded by more than 0.5

year at 12-15 years but the differences are less

for the Todd Atlas at all ages. Figure 10 contains

the modal ages reported by Simmons, after these

have been adjusted to compensate for her use of

the Todd Atlas. The skeletal retardation in the

Simmons group paralleled that of the Todd Atlas,

but it was less at all ages. As noted earlier, this

reflects differences in subject selection.

The data in figure 11 differ markedly. The

mean skeletal ages exceeded the chronological

ages by about 0.5 years in the boys studied by

Johnston, 63 but the mean skeletal ages were

very close to the mean chronological ages in the

Boston youths for whom data were reported by

Greulich and Pyle. 27 There was a definite tendency to retardation of skeletal maturation for

the boys in the group of Fry and Maresh, with

a trend to increasing retardation at older chronological ages. The marked irregularities in

the data of Maresh, at ages after 15 years,

probably reflect fluctuations in group composition, The trends of the mean levels for U.S.

boys obtained from the national survey do not

correspond with any of those reported previously,

but the present national estimates are somewhat

closer from 14 years on to the data from the

later (figure 11) rather than the earlier studies

(figure 10). Corresponding figures illustrate the

reported data for girls (figures 12 and 13). The

levels of the Todd standards are somewhat

closer to those of the corresponding GreulichPyle standards for girls than for boys, but

the Todd standards for girls particularly tend

to increase in relative level with chronological

age. The data of Simmons show a similar trend

and, as for boys, these are in advance of the Todd

standards. The levels of the Flory plates, for

girls aged 12-14 years, are more than a year

behind the Greulich-Pyle standards.

The data for girls in figure 13 are generally

similar to those for boys in figure 11. The modal

skeletal ages for the group of Johnston were

about (.).5 year in advance of the GreulichPyle standards, but the modal ages reported by

Maresh, 65 Fry, * and Greulich and Pyle27 were,

with few exceptions, within 0.5 year of the

Greulich-Pyle standards. As for the boys, these

previous mean values for groups of girls do

not match the National Health Examination Survey data closely either in levels or trends.

It is of interest to consider these reported

means in relation to possible secular changes in

skeletal maturity levels. As far as can be determined, all the groups in studies considered

in this review. were similar in ethnic origin, but

those of Flory61 and Simmons62 alone were of

upper class youths. The median birth dates for

the Flory group are 18 years earlier than those

for the group of Simmons. The skeletal maturity

levels reported by Flory were considerably lower

than those reported by Simmons, indicating a

possible secular trend. Equally, the apparent trend

could reflect differences between these investigators in their criteria for selecting youths as

upper class. The approximate median birth dates

for the group of middle class youths were: Greulich and Pyle (Harvard data), 1935; Johnston, 1940;

Fry, 1953; and Maresh, 1955.27’63-65 These

median birth dates are not the same as those

given in an earlier report 1 because the age

range considered is different. Generalizing across

age and sex, the mean levels reported by Greulich

and Pyle and by Johnston tend to be higher

while those reported by Maresh and Fry tend

to be lower. This could suggest a negative

secular- trend, but the data are difficult to

interpret because the level of comparability

between assessors is unknown, there are severe

sampling deficiencies, and it is reasonable to

assume that there were variations among investigators in what was considered “middle class.”

21
Table C. Relative variability a in skeletal ages (hand-wrist) among youths within selected chronological age groups, by age and sex, from selected studies

Chronological age

BOYS

12

13

14

15

:!

12

13

14

15

16

17

years-----------------

years-----------------

years-----------------

years-----------------

years-----------------

years-----------------

Girls

years-----------------

years-----------------

years-----------------

years-----------------

years-----------------

years-----------------

Flory,

193661

;.;

8:6

8.1

;:;

10.3

9.8

6.7

---

---

---

Simmons,

194462

7.3

6.9

6.7

6.5

W

~:;

.

---

---

---

Greulich and

Pyle, 195927

J;&;t;n,

United

&’ ~4 States,

1966-70

Coefficient of variation

7.2

7.1

;.;

7:9

7.4

9.0

9.1

7.3

6.0

---

---

8.8

8.2

6.6

---

---

---

11.9

9.2

8.8

---

---

---

12.1

11.5

8.7

7.7

;:!

8.5

z:!

4.6

4.7

4.7

‘Coefficient of variation = 100 standard deviation/mean.

Variu b;lity. — Means and standard deviations The relativevariabilityin the sk~~etal ages

of skeletal ages, within chronological agegroups,

have been reported for most of the earlier

investigations considered. Hence it.is possible,

as was done in the previous report on these

findings among children, to compare the relative

variability in skeletal age in relation to the

size of the mean values for youths in these

studies. Greater variability might have been

expected for youths in the present national survey since radiographs were taken throughout

the year rather than close to birthdays orhalfbirthdays as was done in most of the previous

available studies. However, this greater relative variability in skeletal maturity of youths

in the national survey is evident only among

younger boys 12-14 years of age while the girls

tend tobe less variable than those in the smaller

groups studied previously (table C). This same

factor of taking the radiographs throughout the

year could be responsible for the relatively

greater variability at some ages reported by

Fry,a but variability reported by Johnston,63

who also assessed youths at random ages, is not

large. The variability in the group reported

by Fry would be expected to have been somewhat reduced because

Iarge numberof twins.

22

of the inclusion of a

reported by Simmonswz and Johnstonb5 tends to

be the smallest of those reported and among

boys, but not girls, is smaller than for those in

the present national survey when the latter are

grouped into annual age intervals. Presumably,

the lesser relative variability in skeletal maturityin the Cleveland and Philadelphia groups

reflects a combination of factors: greater socioeconomic and ethnic homogeniety in these

groups than in the national survey youths, the

use of fewer assessors in these previous studies

than in the national survey, and differences between these studies in the timing of radiographic

examinations in relation to chronological age.

The effect of the latter can be estimated using

the means and standard deviations calculated for

l-month intervals of chronological age from the

national survey data (table 2). These standard

deviations are about 6 percent lower than those

calculated for annual intervals, while theaverage

of mean values approximates the mean for the

annual age interval. All these same factors also

differ between the sample of Greulich and Pylev

and that of the national survey, but the relative

variability reported by Greulich and Pyle is

generally as$was that reported bySimmons62

and Johnston.
When data are available for each sex in

the group, the relative variability in skeletal

maturity levels from previous studies shows a

tendency to be less for boys than girls except

among Simmon~s group, where the differences

are reversed but negligible (table C). These

previous reports of greater variability in girIs

are in complete contrast with the findings of the

present national survey where boys are the more

variable in skeletal maturity across the age span

6-17 years except at ages 9 and 10 years. When

comparisons are made between girls and boys,

with girls 2 years younger than boys, boys at

8-11 years are slightly less variable while those

from 12-15 years are slightly more variable than

girls 2 years younger, reflecting the fact that

the actual appearance of the skeleton (and thus

the assigned skeletal ages using the same male

standard) tend to be similar in each sex, with

about that degree of retarda&n in boys.

Nicholson and Hanley reported the distributions of chronological ages at which boys

reached the skeletal ages of 12.75 and 16.25

years and girls reached the skeletal ages of

11.25, 14.75, and 17.25 years. These distributions

were close to normal. The youths (n = 61 to

9S in ~:ach group) studied by Nicholson and

Hanley were enrolled in the Guidance Study

(Berkeley, California); the skeletal ages of the

hand-wrist had ~:~ ~zssessed using the Todd

Atlas. M Others, $9 with much smaller groups

than that used in the national survey have reported positive skewness of hand-wrist skeletal

ages within chronological age groups. In the

national survey data the distributions were essentially normal except in older youths in whom

an increasing number of bones had reached the

maximum on the skeletal maturity scale.

The apparent conflicj between the findings of

Nicholson and Hanley 70 and those reported by

some others results from differences in methodology. Nicholson and Hanley reported distributions

of chronological ages at which particular skeletal

ages were reached. This approach avoids problems of truncation due to the end of the skeletal

age scale being reached; there is no effective

limit to the chronological age scale. Also it

avoids problems associated with the ordinal

nature of the skeletal age scale.

Bone-Specific Skeletal Ages

In the Greulich-Pyle method of assessment,

as used in the U.S. national surveys among

children and youths, skeletal ages are assigned

each radio-opaque bone. The skeletal age (handwrist) is determined as the mean of these

bone-specific ages. In the survey among children,

at least 21 of the 31 bones had become radioopaque at 11 years in 99 percent of both boys and

girls. Consequently, skeletal ages could be determined for each of these bones. By age 12

years all but three of the later forming bones

(pisiform, adductor, and flexor sesamoids) were

available for assessment in more than 80 percent of the boys and almost all of the girls. As

in the determination of a single skeletal age for

each hand -wrist, the bones that have become adult

are excluded in the analyses of skeletal age for

individual bones. As a result of these analyses,

national reference data have become available for

levels, variability, distributions, and ranges of

bone-specific skeletal ages.

The means and standard deviations of the

bone-specific skeletal ages for each of the 31

hand- wrist bones of boys and girls 12-17 years

of age in the United States as determined from

the survey male standard, and for girls also

in terms of the female equivalent values, are

shown in table 6 at 1-year chronological age

intervals and in table 7 for selected bones at

6-month chronological age intervals.

Selected percentiles in the distributions for

all of the 31 bone-specific skeletal ages within

single years of chronological age are given in

table 8. In interpreting these tables it must be

recalled that bones that were “adult” did not

have skeletal ages assigned to them and that

such bones are common towardi the end of the

age range considered, particularity in girls.

While there is a consistent increase in mean

skeletal age of youths, with increasing chronological age, for each of the 31 bones in the

hand-wrist, the annual rate of increase generally

diminishes with increasing age from 12-17 years

for both boys and girls (figure 14 and table 6).

Among boys the maximum annual increase

is reached between ages 12 and 13 years (24

bones) or between 11 and 12 years (5 bones). The

23
_ Bo~s-Male Standard

.. . . . . @[s-M~l~ s~~n~~~(j

--- Girls- Fem!le E@Valmt

HAMATE

+60 r

RADIUS +60

[

ULNA

+40

+60

r

CAP[TATE

+40

t

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.

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. :L68 10 12 14 16 16

.s0 LuLu_uu

68 10 12 14 16 16

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r

8CAPHOI0

+0 ~

6 6 10 12 14 t6 t8

*O

r

LUNATE

.60 ~

6810 12 14 16 18

+60

r

Ho TRAPEZIUM

r

TRIQUETRAL

+40

t

+40

+20L40

.200‘“-- --+ ...-. \.\‘“... .

-60

66 10 12 14 16 18

+60

r

TRAPEZOID

+40

t

+40

t

+20

I

. . . . . . .. . . .. . . ...

:+

-\

40 \

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.“”” ....=....” ..+

-:-. 40 ‘x\ .80 6810 12 14 16 18

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68 10 12 14 16 18

*oLuLuuuJ

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+60 METACARPAL III

+40

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METACARPAL I

... >.. /. .,

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[

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8 10 12 14 16

.Gr) ~

6610 12 14 16 6810 12 14 16 16

ffio METACARPAL IV

r

18 18

..

66101214 16 18

+60 r

METACARPAL V +60

r

PISIFORM +60 rADDUCTOR

L

+40 %. ...

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+20 ‘\ “.”....

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68 10 12 14 16 16

CHRONOLOGICAL

AGE IN YEARS

:k6810 12 14 16 18

CHRONOLOGICAL

AGE IN YEARS

CHRONOLOGICAL

AGE IN YEARS

CHRONOLOGICAL

AGE IN YEARS

Figure 14. Mean difference in months between bone-specific skeletal ages and chronological age for the 31 hand-wrist bones

on the male standard for boys and girls and female equivalent values for girls by chronological ages 6-17 years: United States,

1963-70.

24
+60

[

PROXIMAL PHALANX I

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r

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tf)o r

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68 10 12 14 16 16

.ljo6~6

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DISTAL PHALANX I ffio r

DISTAL PHALANX II

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.,0 ~

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r

OISTAL PHALANX V CHRONOLOGICAL

AGE IN YEARS

+40 [

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68 10 12 14 16 18

_ Boys-Male Standmd

.. . . . . . Girls-Male Standard

--- Girls-Female Equivalent

CHRONOLOGICAL

AGE IN YEARS

CHRONOLOGICAL

AGE IN YEARS —

CHRONOLOGICAL

AGE IN YEARS

igure 14, Mean difference in months between bone-specific skeletal ages and chronological age for the 31 hand-wrist bones

on the male standard for boys and girls and female equivalent values for girls by chronological ages 6-17 years: United States,

1963-70.-Con.

25
latter can be seen by comparing the data from

the present survey of youths with those from the

earlier survey of children,l as shown in figure

14. Only the later ossifying adductor and flexor

sesamoids in boys do not show this pattern of

diminishing rate of maturation. Generally the

annual increment between 15-16 and 16-17 years

is about half or less than that between 12-13

years of chronological age.

For girls, when assessed against the male

standards, the maximum annual increase in skeletal age is generally reached 2 years earlier

than for the boys—between ages 10 and 11 years 1

for 27 of the bones and between ages 11 and 12

years for the remaining 4 bones.

The differences between the bone-specific

mean values for boys and girls (female equivalent

values), which had been small at all ages over the

age range 6-11 years in the 1963-65 national

survey, remains small at age 12 years in the

present national study (differences of 4 or 5 months

or less) for all but the later ossifying adductor

and flexor sesamoids. Because these three bones

are relatively late to ossify, they Could be

assessed in only the skeletally advanced boys,

thus explaining why the values for these three

bones in boys are so markedly in advance of

the female equivalent values at age 12 years.

For about half of the bones (15) at age 12

years, the mean skeletal age for boys is less

than for girls (female equivalent values) continuing the pattern found among the children

(6-1 1 years) for all the hand-wrist bones except

the lunate and adductor and flexor sesamoids.

However, from age 13 years onwards for these

15 bones and from 12 years onwards for the

remainder, the mean bone- specific skeletal ages

for boys become increasingly greater than those

for girls, By age 17 years the bone-specific

skeletal ages for boys are about 18-32 months

in advance of the female equivalent means for

girls. The only exception is the radius, where

the mean difference is only about 13 months. Much

of these differences among bones are artifactual.

At older ages, there are some youths in whom the

radius (typically the last hand- wrist bone to

become adult) is the only bone that can be assesed.

Consequently, the exclusion of bones that had

become adult would be less common for the

radius than for other hand-wrist bones. The

necessity to exclude bones that are adult chooses

the slowest maturing girls. In addition, the scale

for boys extends further (in skeletal age months)

than does the scale for girls. The maximum

skeletal ages assigned are greater in boys than

in girls because boys take longer to reach adult

levels.

The differences between the mean bonespecific skeletal ages for boys and those for

girls (when both are assessed as boys) continue

to increase through age 12 years for about half

of the hand-wrist bones (15), as had been

found for almost all the bones among children

6-11 years old (1963-65 national study). From

ages 11 or 12 years on, the mean differences

in skeletal age between boys and girls become

progressively less, decreasing from about 32

months on the skeletal age scale for boys at

age 12 years to 10 months or less at age 17 years

(figures 3 and 14). Some of this decrease is artifactual due to selective exclusion of rapidly

maturing girls. However, much of the decrease

is real, as will be discussed later.

Vavia bility. —The variability of these bonespecific skeletal ages, as measured by the

standard deviations and the interquartile range

U’75 - P25 ), is generally greater among boys than

girls (the latter assessed against male standards)

but tends to decrease in both sexes between ages

12 and 17 years (tables 6-8). Among the youngest

boys (12 years of age), the variability in skeletal

ages for the adductor and flexor sesamoids

(standard deviation of 6-7 months) is less than

half that for the other 29 bones (standard deviations of 16-18 months). This relative lack of

variability occurs because it is only in skeletally

advanced boys at 12 years that those bones can be

assessed. By age 17 years there was slightly

greater variability shown for the radius, metacarpal II, and proximal phalanx I (standard deviation of about 11 months) and substantially less

variability in skeletal ages for metacarpal I

and distal phalanges IV and V (standard deviation

of 4 months) than for the remainder (standard

deviations of 7-10 months).

The standard deviations of bone-specific

skeletal ages for the girls at 12 years, assessed

against the male standards, range from 12-15

months for all the bones except the adductor. and

flexor sesamoids (8-9 months). At 17 years the

26
range of standard deviations is from O-1 month

(capitate, hamate, triquetral, trapezium, trapezoid, metacarpal I, pisiform, and distal phalanges

IV-V) to 7 months (metacarpal II and V and

the flexor and adductor sesamoids). The marked

differences between metacarpal I and metacarpal

H-V in the variability of skeletal age at 17

years reflects differences in the mean ages at

which these bones reach adult levels of maturity (table D).

For girls at age 12 years (female equivalent values), the skeletal ages for the adductor

and flexor sesamoids were also substantially

less variable (standard deviations of 7-8 months)

than for the other 29 bones (standard deviations

of 10-13 months), similar to their findings

from the male standard values. This occurs

because the adductor and flexor sesamoids were

ossified and could be assessed only in the most

rapidly maturing girls in whom little variance

of the ages assigned to these bones would be

expected. By age 17 years variability was negligible (standard deviations of less than 1

month) for nine of the bones— capitate, hamate,

triquetral, trapezium, trapezoid, pisiform, metacarpal I, and distal phalanges IV and V. This

reflects the fact that these bones had become

adult in almost all these older girls and the

few remaining bones that could be assessed

were almost adult. For these remaining bones

the variability in skeletal age, as measured

by the standard deviation, ranged from 1-6 months.

The distributions of the bone-specific skeletal ages (both sexes assessed against male

standards and also female equivalent values for

girls) are described in table 8 by the use of

selected percentiles. The distributions of skeletal age tend to be skewed for many of the

bones but the direction of the skewness differs

‘both among bones within a sex at one age and

also from one age to another for particular

bones. For example, metacarpal V in boys is

skewed slightly to the left at 13 years, to the

right at 14 years, and to the left at 15 years.

No previous studies even of small groups

provide comparable information on bone- speTable D. Modal ages for epiphyseal fusion in the hand-wrist from various studies

Bone Boys Girls

I I

17.2;

16.8

15.018

15.018

15.018

15.018

15.518

15.518

15.518

15.518

15.518

15.518

15.518

15.518

:.;18

14:7::

15.0

15.0;;

15.0

Modal ages from previous studies

18.093 18,318

17.8; l&~,9,

i;:;74 16:491 16.593

15.4;; 16.49~’93

15.4 16.5’”93

16.217’93,16.391

16.3~: 16.4;;93

16”39; %gl 16.5

16.291,93

16.4;;s93

16.491’9316.593

16.493’

& ;91 16.4;;

15.917

15:018 15.893 16.091

16.0~1,9315 ‘7

Rataue ---------

------- ----

Met. X---------

MeC. T.I-III----

Met. W--------

Met. V---------

PP I-----------

PP II----------

PP IU---------

PP Iv----------

PP v-----------

MP II----------

MP III---------

MP Iv----------

MP v-----------

DP I-----------

DP II----------

DP HI---------

DP IV----------

DP V-----------

*Es timetes of median age not possible or not sufficiently reliable for publication. The radius had reached

the “adult ‘tstage for only 26 percent of boys and 53 percent of girls and the ulna in only 51 percent of boys

by 17.9 years.

15.874’93

;;.$

13:574

13.574

13.574

14.Z~j,~3

14.293

::”; 91,93

“ 91,93

;::.:91,93

14.493

14.393

14.293

13.518’91

12.571

13.518

18.5;

15.99193

;:”;93’

14:4~

14.4

14.317

14.518

14.3;J

14.5

14.518

15.018

14.53;

14.591

14”393 13.6

13.518

13.691’93

13.5;: 91,93

13.5 :%93

18.518

14.6;

14.6

:;.:::

.

14.51s’91

14.518

15.0;:

15.0

15.018

13,6’1”3 13.717

United

States

Boys

*

15.;

16.6

16.5

16.6

16.3

15.9

16.1

16.1

15.9

16.2

16.4

16.4

16.3

15.7

15.7

15.8

15.6

15.7

Girls

16.;

13.8

14.8

14.8

14.9

14.0

14.0

14.1

14.1

14.0

14.0

14.1

14.1

14.0

13.4

13.4

13.4

13.4

13.4

NOTES: Met. - metacarpal; PP = proximal phalanx; MP = middle phalanx; and DP = distal phalanx.

Modal ages for studies of Greulich and Pyle27and Pyle et al ?7 have been increased by 0,5 to be more

nearly comparable with assessment methods used in the other studies (see pages 17 and 20).

27
cific skeletal ages of youths in the United States

or other countries.

Range of Bone-Specific Skeletal Ages

As stated earlier, the present assessments

were made bone by bone. In almost every youth

there were variations among the skeletal ages

assigned to the hand-wrist bones. The data for

girls in table 9 are for skeletal ages assessed

against male standards. At each age in each sex,

there is skewness to the left in the distributions

of the ranges with the means being greater than

the medians. Within each hand-wrist the median

ranges tend to be larger in boys than in girls

(table 9). This sex difference is rather small

at 12-14 years (mean differences less than 2

months) but at later ages the difference is

greater (exceeding 3 months), It is maximal

at 16 years where the ranges are 8.8 months

in the boys and 2.3 months in the girls. The

median ranges tend to decrease with age in each

sex; this occurs more rapidly in girls than

boys (table 9). Presumably this greater reduction

in the range for the girls reflects the effects

of several factors. In older girls fewer bones

could be assessed because many had become

adult and the remaining bones differed little in

maturity because all were close to the end of the

scale of maturity. There are corresponding decreases with age in the other percentiles of these

ranges except for some irregularity in the 95th

Table E. Modal ages in years for onset of

percentile level for the girls. This would reflect

the uncertainty of these estimates at the edge

of the distributions. The variability, as measured

by the standard deviation, of these ranges is

greater in the girls than in the boys at all corresponding ages. The differences between the

sexes in variability are relatively small at

younger ages (at 12 years it is minimal; boys

6.83 months, girls 7.42) but become larger as

progressively older ages are considered. At

16 years the difference is maximal with standard

deviations 8.94 months for the boys and 12.25

for the girls. The variability was marked. When

variability is considered as the coefficient of

variation in relation to the magnitude of the mean

(lOO.X/Y) it exceeded 100, i.e., standard deviation greater than the mean, in older youths of

both sexes (boys 17 years, girls 15-17 years).

No previous studies provide information

about the ranges of bone-specific skeletal ages

in the youths of the United States or any other

country.

Onset of Ossification

From the skeletal age assessments among

youths in the present national study, it is possible

to obtain reliable estimates of the ages of onset

of ossification for the two bones in the hand-wrist

that generally are the last to become radioopaque— the adductor and flexor sesamoids (table

E). Data on the age of onset of ossification for the

ossification in selected late appearing

bones from various studies

. .

Bone and sex

Boys

Adductor sesarnoid ------------

Flexor sesamoid --------------

Girls

Adductor sesamoid ------------

Flexor sesarnoid --------------

United

Modal ages from Previous studies States.

12.171

13.527

10.572

11.027

12.617

10.773

12.772

10.827

12.873

11.017

13.227

11.293

12.5

14.2

10.7

13.0

NOTE: Modal aszes for studies of Greulich and Pvle 27 and Pvle et al. 17 have been increased by 0.5 t; be more nearly comparable with a assessment- methods used in the other

studies (see pages 17 and 20).

28
adductor sesamoid among girls, which could be

reliably estimated from the preceding national

study among children age 6-11 years, are included

in this table for comparative purposes.

While all of the later-forming bones that

normally ossify during the age period 6-17 years

tend to ossify earlier in girls than in boys, these

median ages of onset for the flexor sesamoid

show the least acceleration of girls over boys.

Previous studies of onset of ossification have

included three types of modal ages: (1) median

ages at onset, (2) mean ages at onset, and (3)

the percentage incidence of ossified centers within

age intervals. The latter data allow the calculation

of modal ages after plotting on probability paper.

To facilitate comparison, it has been assumed

that any systematic differences between corresponding mean and median ages and ages when

the center is present in 50 percent of youths,

that are due to the method of analysis, can be

disregarded. The only bones with modal ages

at onset of ossification in the age range 12-17

years are the adductor sesamoid and the flexor

sesamoid in boys.

The data of Greulich and Pyle 27were obtained

from the Brush Foundation Study of Cleveland

youths; these were of high socioeconomic status.

These investigators had available mixed longitudinal data from more than 200 boys at each

age. A subgroup of these youths (30 boys) was

used by Buehl and Pyle71 to obtain the mean age

of os~;fication of the adductor sesamoid. Pyle

et al. reported data from the group of Boston

boys described earlier in reference to the skeletal age data of Greulich and Pyle. n Many of

the boys in this group~zwere included among those

studied by Harding. The mixed longitudinal

data of Garn et al.73 were derived from middle

socioeconomic class white youths in Southwestern

Ohio born between 1929 and 1966. The group

included about 180 boys who were radiographed

near birthdays and half - birthdays.

Lurie et al.74 reported cross-sectional data

from 1,129 Cincinnati white youths born between

1920 and 1940. These youths were examined at

the Child Guidance Home of the Jewish Hospital.

While not necessarily Jewish, they were referred

because of emotional disturbances. Although data

from youths with endocrine disturbances or

marked nutritional deficiencies were excluded, the

normality of the remainder of the group is questionable. Consequently, these data have been excluded from the present review. Similarly, the

data of Howard ~ have not been included because

the ethnic nature of this group was not reported.

It should be noted, however, that his data show

a modal age for onset of ossification of the

adductor sesamoid in boys of 13.25 years.

Considerable variation would be expected

between findings from these reports because the

studies differ in many respects, particularly

selection of subjects and the methodology of

radiography and data analysis. Furthermore,

while Garn et al. 73 and Harding72 reported data

relating to the age at which a center was seen

to be ossified, Greulich and Pyle n and Pyle

et al. 17 recorded an age for onset of ossification

in each youth that was interpolated between the

last radiograph in which the center was not ossif ied and the first radiograph in which it was

ossified. For this reason, the means reported

by Greulich and Pyle 27 and by Pyle et al. 17

are systematically about 0.5 year in advance

of those that would have been reported had the

alternative procedure been followed. The report

by Buehl and Pyle 71 does not state whether an

interpolated age was used.

The modal ages based on reported data that

are included in table E should be interpreted with

care because of these methodological differences.

In compiling this table, 0.5 year was added to

the ages reported by Greulich and Pyle a and

Pyle et al. 17 After this adjustment, the various

reports concerning the adductor sesamoid are in

reasonably close agreement except for the earliest and the latest ages, which are from the

Brush Foundation n and the Harvard Growth

Study,17 This unexpected difference is not likely

to be associated with the observer because Pyle

was intimately involved with each study. It could

reflect a possible lack of interpolation by Buehl

and Pyle or that the subsample used by these

authors was unrepresentative of the total Brush

study group. It is noteworthy that only one previous

report has been made of the ag~ at onset of

ossification in the flexor sesamoid.

The modal age at onset of ossification of the

adductor sesamoid in the boys included in the

national survey is within the range of ages reported previously for smaller nonrepresentative

29
groups of United States youths. However, the ages

for the onset of ossification in the flexor sesamoid,

both in the boys and girls, are considerably later

.

in the HES data than in the data reported previously by others. The onset of ossification in

the adductor sesamoid can be recognized easily.

Consequently, observer reliability is high and the

radiographic quality can vary within wide limits

without markedly affecting the data. The recognition of early ossification in the flexor sesamoid

is more difficult because, commonly, its radiographic image is superimposed on that of the

head of the first metacarpal. Review of some

of the national survey radiographs indicated that

they were of unusually good quality and that even

very small areas of ossification in the cartilaginous models of the hand-wrist bones had

been recognized by the assessors.

Epiphyseal Fusion

Each bone of the hand-wrist, except the carpals, reaches adult levels of maturity when fusion

is completed between the epiphysis and the diaphysis. This stage of maturation was not recorded

as such in the national survey, but, as was done

for onset of ossification, it can be calculated

from the skeletal ages that were assigned. Making

the obvious assumption that fusion had been

completed in any of these bones that were assessed as adult, and using the percentage incidence

of such bones across age, estimates were made

of the ages at which epiphyseal fusion was complete

in 50 percent of the youths for each bone (table 10).

In interpreting these estimates, it should be

recalled that they refer to the total noninstitutionalized U.S. population of youths 12-17 years.

As expected, the data show that fusion tended to

occur earlier in girls than in boys. The median

ages at fusion for boys ranged from 15.6 years

for distal phalanx IV to 16.6 years for metacarpal II, III, and V among the 19 hand-wrist

bones for which such values could be determined.

Among girls, the median age at fusion for these

same 19 bones ranged from 13,4 years for the

distal phalanges I-V to 14.9 years for metacarpal

V and to 16.2 years for the ulna, The number

of boys and girls in whom fusion had occurred

in the radius, and the number of boys in whom

fusion had occurred in the ulna by age 17 years

is insufficient to provide a reliable base for

determining the median ages at fusion for these

later maturing bones.

Girls tend to reach the adult level of maturity for these 19 hand-wrist bones about 2

years earlier than boys. The greatest spread

between boys and girls—26 months or more—

is for the proximal phalanx I, middle phalanges

II-V, and distal phalanges I-V; the least difference is observed for the metacarpal IV and

V—20 months.

These findings can be considered together

with those for the mean skeletal maturity of the

total hand-wrist. The mean of the separate median

ages when fusion was complete for the individual

bones for which estimates were possible within

this age range in the national survey of youths

was about 16.2 years for the boys and 14 years

for the girls (table D). At these chronological

ages, the mean skeletal ages are, by interpolation from table 1, about 193.4 months for the

boys and 192.3 months for the girls. The close

correspondence between these two values attests

to the internal consistency of the present data.

Since both sexes were assessed against the same

set of male standards, the means of the assigned

skeletal ages should have been similar, but not

necessarily identical, in the two sexes at the

ages when fusion had occurred in 50 percent of

the boys and girls. A similar picture emerges

if a corresponding analysis is made for the ages

when half of all hand-wrist bones have become

adult (table 5).

Previously reported ages at epiphyseal fusion

for childwn in the United States. –Considering

the importance of epiphyseal fusion as the last

sequential maturational change in a long or short

bone, and its significance in relation to the

cessation of elongation, the paucity of previous

data is surprising. In part this reflects the tendency for selection or “sampling” in growth

studies to be based on readily available subjects,

for example, kindergarten groups or children of

cooperative parents. In general epiphyseal fusion

occurs during the latter years of enrollment at

high school; it is more difficult to obtain the

cooperation of these youths.

Despite the relative lack of reported data,

the importance of this stage of maturation has

been realized. Schemes for grading the progressive stages of fusion within a bone have

30
been developed. 18’33’75s0 In essence, all these

were Ixised on the early work of Hasselwander. 81

But why were these schemes not applied

more widely? Apart from the problems of obtaining subjects, it is difficult to interpret radiographs, in respect of epiphyseal fusion, towards

the end of the maturation of a bone. As has

been pointed out, even minor variations in radiographic positioning can cause appearances on a

radiograph that are interpreted as fusion when,

in fact, fusion has not occurred. 82J83 There is

truth in the claim of Sahay M that it is quite

easy to give an ununited epiphysis the appearance

of union by directing the cone of X-rays obliquely. However, the difficulties can be exaggerated. 18*34Y*S!*6 For example, it is surprising to find a colleague of Todd claiming

that one cannot rely too confidently upon the

apparent condition of union or of nonunion in

a radiograph because it is merely a confusing

medley of shadows.75 To some extent the uncertain y of classification can be overcome? 5

Other difficulties result from the fact that

workers have differed in the criteria they have

applied for the recognition of epiphyseal fusion.

When fusion occurs, there is no longer a radiolucent zone at the level of the junction between

the epiphysis and diaphysis. Instead a thick

radio-opaque line forms at this level. Some have

interpreted the presence of this line as indicating

that fusion occurred, recently; n others have considered that fusion is incomplete while this

line is present.n These views are unreasonable because the line can remain for very

long periods. 78’84*88-91 In most studies, the

persistence of a radio-opaque line at the level

of fusion has not precluded classification as

“fusion completed. I!89? 90~ 92 However, it has been

fairly standard practice not to regard fusion

as complete if a notch remains in the cortex

of the bone between the epiphysis and diaphy -

sis 89, 90

,

The modal ages reported for epiphyseal

fusion in the hand-wrist from selected studies of groups of United States children have

been included in table D. Although many ages

are given in the table, the lack of satisfactory data cannot be overemphasized. The data

of Lurie et al.74 have been included despite

doubts as to the clinical normality of the children in the groups, as stated earlier. These

authors did not report their radiographic criteria

for the recognition of fusion. Pryor32reported data

from 145 youths examined cross-sectionally. He

concluded that epiphyseal fusion occurred 3-4

years earlier in girls than in boys but did

not report ages for individual bones except

the radius and ulna, which he considered fused

at 17.25 years in girls.

The group studied by Hansman 93 consisted

of white youths of above average socioeconomic

status who were radiographed at 6-monthly intervals in the Child Research Council, Denver,

Colorado. These youths were born between 1915

and 1941, and the group from which relevant

observations could be made exceeded 30 in each

sex for each bone except the radius and ulna.

Hansman considered fusion was present when epiphyseal union was complete, although the line of

fusion might still be visible. The data of Todd18

have been included in table D despite difficulties of interpretation because so few other data

have been reported. His analysis was based on

findings in 200 skeletons of known age and sex,

after excluding the obviously abnormal. He reported the “usual range” for age at fusio% the

midpoint of this range for each bone has been

included in the table.

The group of Pyle et al. 17 consisted of youths

living in or near Boston who were enrolled in

the Harvard Growth Study. These middle class

white youths were born between 1930 and 1939

and were radiographed annually. It was considered that fusion was present when all the

epiphyseal cartilage had been replaced. The

size of the group was very small, varying between 11 and 13 for each bone in each sex. In

interpreting these data it is necessary to consider the statement by Pyle et al, 17 that the

34 boys include the relatively earlier maturing

males because the study was discontinued before

all boys had matured.

Accordingly, the group of 44 girls included

a more representative sampling of later maturing

individuals than did the group of boys. Furthermore, the ages recorded by these authors were

midway between those of the annual radiographs

in which fusion first appeared and the last in

which it was still absent. To make the reported

data more comparable across studies, 0.5 year

31
was added to each of the mean ages reported

by Pyle etal.17 before these ages were included

in table D.

The data of Buehl and Pyle 71 were obtained

from annual serial radiographs of 30 boys and

30 girls in the Brush Foundation Study. These

were upper class white youths living in Cleveland.

Garn et al.91 reported findings from 6-

monthly serial radiographs of 107 white youths

in Southwestern Ohio who were above average

socioeconomically. Fusion was considered present when the epiphyseal plate was completely

replaced by bone.

Ages at epiphyseal fusion in the macerated

skeletons of United States male war dead have

been reported by Vandervael w and McKern and

Stewart.95 The age ranges of these groups do

not allow reliable estimates of modal ages at

fusion.

The investigators whose reported data are

included in table D and who based their studies

on radiographs have differed in their verbal

descriptions of the criteria they used to categorize “fusion.” Nevertheless, the differences

between these criteria appear slight.

The data in table D show, as expected, that

fusion tends to occur at younger chronological

ages in girls than in boys. The only dissenting

view is that of Todd, W 34,76 who considered,

as a general rule, that there were no sexassociated differences in maturity levels at

chronological ages after 16.5 years. His view

was in conflict with that of several other workers, especially Pryor.32 Possible reasons for

this conflict that are associated with the nature

of the skeletal age scale are considered in the

“Discus sion. 1!

Despite methodological differences and inadequate samples, there is fair replication across

the reported studies and fair agreement with the

findings from the national survey. Generalizing,

in each sex the order of mean ages of fusion for

rows of bones is distal phalanges, first metacarpal, middle and proximal phalanges, the remainder of the metacarpal, radius, and ulna.

There is, however, no difference between the

proximal and middle phalanges in their mean

ages of fusion in the national survey girls. Comparison with data from the large group studied

by Garn et al. 91shows good agreement in regard

to patterns of mean ages, but those reported

by Garn et al. are about 0.3 year kitei. There

is no evidence of a trend for the mean ages of

fusion to differ across rays, e.g., for an order

from the radial to the ulnar side of the handwrist. A ray is a metacarpal with its associated

proximal, middle, and distal phalanges. In general, the ages reported by Todd are earlier,

with the major exceptions of the radius and ulna

in girls. For these bones he reported very late

ages that were equal to, or almost equal to, the

ages for the boys. In contrast to Todd, the ages

reported by Hansman?3 Pyle et al.,17 and

Garn et al.91 are in close agreement for almost

all bones. The sex difference in the timing of

fusion is about 2 years for each bone-the difference is similar for the study of Pyle et al.17

despite differences in sampling between the

two sexes that might have reduced the difference. Perhaps similar sampling bias of overrepresentation of early maturing boys was present in the studies by others but went unrecognized. In the national survey data, the sex

difference in the timing and fusion is also about

2 years for each bone.

The reported data provide little basis for a

comment about variability. Standard deviations

of 0.9 to 1.1 years were reported by Pyle et al.,17

but because of the extremely small sample

size and the unrepresentative nature of the group

of boys studied, little reliance can be placed on

these figures.

YOUTHS ALSO

EXAMINED AS CHILDREN

As previously indicated the Health Examination Survey among ‘youths in 1966-70 utilized

the same sampling areas and housing units as

the previous Health Examination Survey among

children in 1963-65. As a result, 2,177, nearly

one-third, of the 6,768 youths in the present

study had been examined in the children’s survey

also. Radiographs satisfactory for skeletal maturity assessment were available from both survey examinations for 2,106 of these youths. This

group included about 52 percent boys and 48

percent girls, as did the total sample of examined

youths. At the younger ages of 12-14 years these

32
skeletal maturity data at two points in time were

available for about 50 percent of all examined

youths in those chronological ages but only about

one-fourth at 15 years and only 1 percent at

16 years. The time lapse between the two examinations ranged from 28 months to 5 years,

with a median time lapse of about 4 years,

The skeletal maturity levels for the entire

hand-wrist and for the individual bones among

this subgroup of youths at the second examination

are similar to those for all youths in the present study. At each chronological year of age

from 12 through 15 years, the mean values for

all youths and those also examined as children

are in close agreement (tables 1, 6, and 11).

Only a few of the younger 16-year-old youths

and none of the 17-year- olds had been in the

preceding survey.

Because of the fact that not all eligible

children returned for reexamination in the youths’

survey, comparison of their skeletal maturity

levels as children with all children in the previous survey is more difficult. The 12-year-old

youths would have been 7-10 years of age, the

13-year-olds 8-11 years, the 14-year-olds 9-11

years, and the 15- year-olds 10-11 years. Comparison of the mean skeletal maturity levels

at the time they were children in 1963-65 for

the three youngest age groups of youths, 12-14

years, show them to have been more advanced in

this respect than all the children 8-10 years of

age examined in 1963-65.1 This is not inconsistent with their method of selection. There is no

evidence of systematic differences in the assessment methods used in the separate surveys of

children and youths. In fact, every effort was made

to apply exactly the same assessment methods to

both sets of radiographs.

Comparison of the ranges of increases in

skeletal and chronological ages for those youths

examined at two ages shows the expected greater

range in skeletal ages (male standards) than

chronological ages for both boys and girls (figure 15). For both sexes, increases in chronological ages range from 24 through about 59 months,

whiIe increases in skeletal age for these same

youths range from a minimum of 18 months to

about 83 months. The proportion showing small

skeletal age increases of 18-35 months is substantially lower in the girls than the boys (both

based on assessments against the male standards), while proportionally more girls than

boys show increases of 48-83 months in skeletal

maturity during the roughly comparable time

period (figure 16).

Comparison of the increase in skeletal age

(hand-wrist) within 6-month chronological age

intervals shows the extent and pattern of agreement in these two measures of age in girls and

boys (table 12). The skeletal age data for both

sexes are in terms of the male standard. On this

basis, boys were more than twice as likely as

girls to show skeletal age increases that were

40 r

BOYS

.... ch~~no[@ml age

—Skeletal age-(Mde Standard) ;

30 -

/{

,,

/:

;:

,A.. ; :

,,’:$:

20 -

‘.$:

/ :/ :

10 - J+

J

01 t , , I , )

12 24 36 4S 60 72 S4

*

MoNTHSINCREASEINAGEFROMFIRSTTO

SECONOEXAMINATION

Figure 15. Percent distribution of months increase in chronological and skeletal ages (male standard) between first and second examination for boys and for girls in both the Health

Examination Surveys of 1963-65 and 1966-70.

33
— Boys-Male Standard

.. . . . Girls-Male Standard

g

g

i;

&

- 7“’”R . . ...-”

0

0 12 24 36 48 60 72 64

MONTHS INCREASE IN SKELETAL AGE FROM

FIRST TO SECONO EXAMINATION

(196365 to 1S5S-70SURVEY)

Figure 16. Percent distribution of months increase in skeletal

age (male standard) from the first to the sacond examination

for boys and girlsin both the Health Examination Surveys of

1963-65 and 1966-70.

3 months or more less than their chronological

age increases between the two examinations

(25 percent for boys compared with 10 percent

for girls); girls were slightly more likely than

boys to have a skeletal age increase 3 months

or more greater than their actual increase in

age between the two examinations (55 percent

compared with 46 percent). Nearly 33 percent

of girls and 29 percent of boys had skeletal age

and chronological age increases between the two

examinations that agree within 3 months,

A comparison of skeletal maturity in relation to chronological age (skeletal age less

chronological age) for youths included in both

surveys is given in table 13 and figure 17. There

are changes in the distributions of these differences ‘between the two surveys. A greater

proportion of the boys show marked advancement

of skeletal age at the second than at the first

examinat ion—this would be expected from the

general trends in these differences when data

from the whole sample at 7-11 years are compared with those at 11-15 years (figure 3). The

pattern of greater advancement in skeletal age

than in chronological age for the girls (table

12) is reflected in table 13 and figure 17. At

the time of the se~nd examination, smaller

proportions of girls had skeletal ages that were

less than the chronological ages; correspondingly, more of the girls had skeletal ages that

were in advance of their chronological ages.

This is in agreement with the data for the com30- SOYS

,... HEs, l!33.~5

- HES, 191X3.70

?

~. 20 -

= ‘0 -A /

. ..

,.. ‘.+,

%...,

o 1 1 I t 1 I I

46 .36

I

-24 -12 0 12 24 26 4f

Y

~ 20

w

L

g

;8..

. . . . . .

..

z ...

= 10 -

E

.,””

..-

...’.

. ..+”

0 1 I

-4s

1

-36 -24 -12 0 12 24 36 48

SKELETAL AGE (MALE STANOAROI LESSCHRONOLOGICAL

AGE (MONTHS)

Figure 17. Percent distribution of differences between skeletal

and chronological ages at the time of the first and the second

examinations for bow and qirls in both the Health Examination Surveys of 1963.%5 and-l 966-70.

plete samples. These showed much higher levels

of skeletal maturity (expressed as skeletal age

less chronological age) for girls aged 11-15

years than for girls aged 7-11 years.

These findings should not be interpreted

as showing secular trends. Rather, as discussed

at length in relation to figure 3, they reflect the

lack of correspondence between the age equivalents assigned to the standards of reference

that were used and the actual levels of skeletal

maturity in the national probability samples

that were examined.

DISCUSSION

To interpret the findings included in this

report, it is necessary for the reader to be

fully aware of the sampling and weighting meth34
ods employed and system of radiographic

assessment applied. Reference has been made

to these subjects under “Method,” and some

aspects are considered more fully in appendix

I. In summary, radiographs of the right handwrist were assessed for skeletal age. These

radiographs had been obtained by examination

of a cross-section of noninstitutionalized youths

12-17 years in the United States. A probability

sample of 7,514 youths was selected and 6,768

of these (90 percent) were examined. However,

32 of the radiographs were not taken or were

unsuitable for skeletal age assessment. The

very small number of missing or unsatisfactory radiographs attests to the high quality

of the field procedures. The sample examined

is closely representative of the total United

States population of youths 12-17 (22.7 million).

Nevertheless, estimates from the present sample

of youths are slightly less reliable than those

from the previous survey of children because

96 percent of the selected children were examined.

Data were not estimated for those selected

in the sample who were not examined. Instead,

it has been assumed that the distribution of

skeletal maturity levels for the nonexamined

would be similar to that among the examined

youths of the same chronological age, sex,

race, geographic region, and socioeconomic

background. Finally, the data from each examined

youth were weighted with the reciprocal of the

sampling ratio used for that part of the total

population he was selected to represent. This

weighting allowed national estimates appropriate

for the total population of noninstitutionalized

youths. The same sampling and weighting procedure had been followed in the previous analysis :f skeletal age in U.S. children 6-11

years. Consequently, direct comparisons can

be made between the reports for children and

youths and in combination they provide national

estimates for the age range from 6 to 17 years.

These sampling and weighting procedures should

be recalled when the findings from the national

survey are compared with earlier reports by

others. Earlier studies have been of much smaller

groups of children selected on the basis of

convenience, e.g., attendance at schools near

the investigator.

The radiographs were assessed using the

HES set of standards that was prepared for

the survey. 8 Each bone was assessed to the

nearest month of skeletal age by medical students who were trained by Dr. S.1. Pyle and

whose reliability was monitored throughout the

period when assessments were being made (appendix I).

The method of skeletal age assessment

selected for the survey, on the advice of anthropologist consultants, is essentially the same

as that applied ~when the well-known Greulich

and Pyle Atlas is used. Most of the plates

in the HES Standard were taken from the Greulich- Pyle Atlas, but they appear to be of right

hand- wrist because they were turned over photographically.

There was one important departure from

standard practice. The assessors did not know

the chronological age, sex, or race of any child

whose radiograph was being assessed. All children were assessed against standards for males;

all were assigned male skeletal ages. This

approach has obvious advantages and some disadvantages. It can provide a much better estimate

of sex-associated differences in the skeletal

maturity levels of youths than has been available

previously. These differences are unbiased and

are expressed in months of skeletal age (male).

Typically, girls mature more rapidly than boys

and, consequently, within chronological age

groups, the mean skeletal ages for the girls

exceed those of boys when both are assessed

against the same set of standards. In the usual

method, boys and girls are assessed against

sex-appropriate standards and the sex differences

between the mean skeletal ages for groups of

the same chronological ages are generally small.

In the Health Examination Survey the data

for girls were transformed, bone by bone for

each youth, to “female equivalent values. ” The

data used for this transformation were provided

by Dr. Pyle. As will be discussed later, these

data appear to allow appropriate transformations

at most ages considered but not near the “adult”

end of the skeletal maturity scale.

When skeletal age assessments are made,

there are limits to the range of ages that can be

applied to each bone. Bones that are not radioopaque cannot be assessed; the youngest age

35
that can be applied to a bone is between the level

of the last standard in which it is not radioopaque and the level of the first standard in which

it is radio-opaque. The maximum age that can be

assigned is 1 month less than the “adult” level.

Application of these minimum and maximum

levels (table A) resulted in some bones being

excluded when the mean of the bone-specific

skeletal ages was calculated to obtain a single

value for each hand- wrist. Additionally, some

youths were excluded completely because all

their hand-wrist bones had become adult. The

proportion of youths that was excluded for this

reason was zero in each sex at 12 years but

increased to 10 percent in boys and 22 percent

in girls at 17 years. This exclusion resulted

in an underestimation of the skeletal maturity

of older youths, but the effect of this was smaI1.

On the male standards, when means for age

groups are considered, the effect could be no

greater than 2.5 months in boys and 3.8 months

in girls, even at 17 years.

Mean Skeletal Age (Hand-Wrist)

In the previous study of children 6-11 years, 1

the mean skeletal ages for boys were lower than

the corresponding chronological ages by increasing amounts until the difference was 13.8 months

at 11 years. Some retardation is present in

boys 12-17 years but, in general, the amount

decreases with age from 9.8 months at 12 years

to an advancement of 0.5 month at 15 years

and a retardation of 4.6 months at 17 years.

It is emphasized that these changes with increasing chronological age cannot be due to

assessor bias or variations in the survey sampling, but the changes from 15-17 years are

mostly artifactual. They are due to the scale

by which skeletal maturity is assessed and to

the fact that the maturity levels of most of the

boys were near the end of the scale. However,

if the maximum allowance is made for the

exclusion of boys in whom all the hand-wrist

bones were adult, a retardation still develops

between 16 and 17 years in respect of the standards against which they were assessed.

The mean skeletal ages of the girls, assessed

against the male standards, are advanced (greater

than the chronological ages). The extent of this

advancement increases from age 9-11 years in the

earlier study of children, 1 and this increase

continues to 12 years. At 12 years, the mean

skeletal age exceeds the mean chronological

age by 24.9 months. Later, the amount of advancement decreases until it is only 1.5 months

at 17 years. This decrease is due partly to

the exclusion of girls (22 percent at 17 years)

in whom all the hand-wrist bones were adult.

The estimates of skeletal age for 6-monthly

chronological age intervals from the survey of

children for the age range 11 years to 11 years

5 months and from the survey of youths for the age

range 12 years to 12 years 5 months are in

excellent agreement for boys (a mean increment

of skeletal age of 6.5 months during the 6-month

interval), but the agreement for girls is less

good (a mean increment of 11.8 months in skeletal

age during the 6-month interval).

The occurrence of mean differences between

the chronological and skeletal ages demonstrates

that the calibration of the scale is imperfect when

used to assess a national probability sample of

United States youths. This study does not, however, provide any information as to whether the

ovder of maturity indicators is correct within

the maturity scale of Pyle et al.8

One major advantage of the method of assessment employed was that direct unbiased

estimates of sex-associated differences were

obtained. This was possible because all assessments were made against a single set of

standards by observers who did not know the

sex of any child. The mean differences found

(in male skeletal age months) increase slightly

from 32 months at 11 years to 35 months at

12 years, but then they decrease gradually to

reach 6 months at 17 years. The general consistency of the national survey data is attested

by the close correspondence between the estimated sex differences at the junction between

the age spans studied in the survey of children

and the present survey of youths.

The differences reported previously are

compared with these values in table F. The method

by which Pyle et al.8 estimated these sexassociated differences is described in detail in

their text. At 12 and 13 years their values are

close to those obtained in the national survey, but

later the survey differences are considerably

36
Table F. Sex differences in skeletal age months (male) from various studies, by

chronological age

A B

Chronological age Pyle et al., Todd United

196117 193136 Roche, Roche States,

196897 19689? ~966- 70

Skeletal age in months

12 years .------- ---------------- ------ 32 15 19 19 34.7

13 years ------------------------------ 29.2

14 years ------------------------------ . ;; --~ .;: ;: 24.4

15 years ------------------------------ --- 24 19.1

16 years -------- ----------------- ------ 24 --- 23 ;; 14.9

17 years ------- --’----- ------- ------- -- 22 --- 24 23 6.1

A = based on the Greulich-Pyle Atlas,(1959).27

B = based on the method of Tanner et al. (1962).98

larger. The estimates made by Todd96 are much

smaller than those from the national survey.

Todd had data from only asmallgroupofchildrenand itis not clear how he arrived atthese

estimates. Roche97 estimated these differences

by assessing the female standards in one copy

of the Greulich-Pyle Atlas against the male

standards in another copy. The estimates obtained are considerably smaller than the survey

estimates at 12 and 13 years and considerably

larger at 16 and 17 years. Roche 97 also estimated these differences from the skeletal age

equivalents for each sex assigned to particular

scores by Tanner etal.98 These differences are

very similar to those obtained by the same

investigator when usingtwocopies oftheGreulichI?yle Atlas.

The occurrence of smaller differences in

the national survey data than in those reported

by others for 16 and 17 years may be partly

artifactual. Ifthem.aximum allowance weremade

for those youths excluded because a?lthebones

of the hand-wrist were completely adult, the

differences in the survey data would become

15.2 months at 16 years and 8.4 months at

17 years (table B). It is clear that this factor

was not of major importance. A further artifact, almost certainly trivial, results from the

use of “A-6” to designate a maturity level

within 6 months of the adult level. This procedure would have led to a slight underestimate,

and the effect would have been more common in

older girls than in older boys. The sex differences in skeletal ages towards the end of

the scale, as recorded in the present survey,

vary considerably from those reported by ear-”

lier workers, but they are certainly not entirely artifactual. This is shown by the close

correspondence between the sex differences in

mean skeletal ages and those in the median

ages at onset of ossification in specified numbers of bones (table 5 in the report of the

children’s survey and table 5 in the present

report) both at younger and older ages.

It will be recalled that in the national

survey bones that had reached adult levels of

maturity were excluded when the mean handwrist skeletal ages were calculated for individuals. In each sex there is general agreement among previous reports that the last handwrist bones in which epiphyseal fusion occurs

are the radius, ulna, metacarpal, and proximal phalanges.18’ 74’93 At older ages the survey

data became more dependent on these bones because the other hand-wrist bones had become

adult. However, the data of Pyle et al! and of

Roche 97 indicate that the sex-associated differences for these bones are similar to those

for the whole hand-wrist at 16 and 17 years. Consequently, it is unlikely that the dependence of the

survey means on these bones at older ages would

be responsible for the differences between the

present and previous findings.

These variations between the present findings

37
and those reported by others could not be explained entirely by the absence of bias in the

survey data. Presumably they are due to inadequacies in the maturity scales for boys

and girls towards the end of maturation. Nevertheless, they are puzzling because the median

ages at which fusion occurs in the hand-wrist

in youths examined serially differ, between boys

and girls, by about 2 years (Roche, unpublished

data). Because of these problems with the sexassociated differences near the upper end of the

maturity scale, there is doubt about the accuracy

of the female equivalent values at these ages.

Consequently, in this discussion the emphasis

has been placed on the data obtained when the

radiographs for each sex were assessed against

the male standards. It is considered that the

findings for girls assessed against the male

standards represent more accurately the real

biological changes that occur than do those ~btained after transformation to female equivalent

values.

The changes across age in the mean differences between skeletal age and chronological

age are shown at yearly intervals in figure 3

and at 6-month intervals in figure 7. Considering

ages as originally assessed from the”male standards, there are prepubertal decelerations and

pubertal accelerations in each sex. The maximum advancement (SA>CA) is reached at 12

years in girls and 15 years in boys; later there

are decreases in each sex. It is apparent that

the male HES Standard, against which both the

boys and girls were assessed, does not match

the mean skeletal maturity levels for the national sample of boys. If the data for the girIs

are adjusted for these differences between the

national survey boys and the male set of standards, as is done in figure 6, the mean differences between skeletal and chronological age

for the girls, assessed against male standards,

show a very definite spurt, with a peak at 12

years. These cur~es are difficult to interpret

because the skeletal maturity scale is ordinal.

However, due to the transformation of the data

for girls to a male set of standards with a

markedly improved calibration, a pubertal spurt

in girls has been demonstrated even more clearly

than in the original data.

This transformation, so that the mean skeletal

ages for the boys matched their mean chronological ages, was not ideal because it obscured

the pubertal spurt in the boys. This directs

attention to one problem with the present scales

of skeletal maturity. Essentially, these were

constructed by selecting the youth at the median

skeletal maturity level in each chronological

age group. This procedure tends to bury any

pubertal spurt in the scale and makes it’ more

difficult to demonstrate a spprt when the scale

is applied.

The adjustment of the mean skeletal ages

for the girls, assessed against the male standards, to what they would have been if each

mean skeletal age had equaled the corresponding

chronological age in the boys, is an improvement

because the boys’ scale is then calibrated to

match exactly the mean levels in the national

probability sample. However, it is not ideal.

The data in figures 3 and 6 demonstrate a

definite pubertal spurt in the girls and a much

smaller spurt in the boys. If a cardinal scale

were available, it is probable that the spurt

would be of similar magnitude in each sex and

it would tend to occur about 2 years earlier

in girls than boys. Furthermore, even an ideal

scale developed from cross-sectional data would

not reflect accurately the pubertal changes in

individuals. The latter would be more abrupt

than those for a group in which some “averaging”

occurs across age due to variations in the

timing of pubescence. This effect is well known

for measures such as height and weight.99

One further step could be taken in adjusting

the survey data. If it is assumed that the pubertal

spurt in maturity is of similar magnitude in each

sex, it is clear that part of the spurt in the boys

has been concealed in the male skeletal maturity

scale because the apparent spurt is much smaller

in boys than girls (figure 3). If an adjustment

were made for this, the girls’ spurt would be

slightly less marked and the deceleration would

be more rapid than in the original curve or the

previously adjusted curve (figures 3 and 6). Furthermore, if this new adjustment were made, the

peak of the curve would shift to 11 years, which

would be plotted at 11.5 years. This possible additional adjustment has not been made in figure 3

or figure 6.

The effect of scale selection on apparent

38
*

spurt size would be demonstrated if all the survey radiographs were assessed against a single

standard for girls. It is hypothesized that, if

this were done, the apparent spurt in the boys

would be much greater than that in the girls.

These sex differences in the apparent size of

the spurt would not be evident if the timing of

the spurt were the same in each sex.

Scale selection may have less influence on

the timing of the apparent pubertal spurts in

skeletal maturity. When the national survey

radiographs were all assessed against the male

standards of Pyle et al.,8 the peaks of the

spurts (mean values) occurred at 12 years in

girls and 14 years in boys. These ages, and the

difference between them, are close to what

would be expected.

If a pubertal spurt in skeletal maturation

occurs, as suggested by Todd 18 and FIory, 61

and if this were built into the male skeletal

maturity scale, several effects would be expected in data of the present type. If the maturity scale were ideal, the mean differences

between the skeletal and chronological ages

for the boys would be zero at all ages. The

scale is, however, set much too high for boys

aged 9-13 years (figures 18 and 19). If the girls

were assessed on an ideal boy’s scale, it would

be expected that the mean differences between

skeletal age and chronological age would change

during pubescence in the way observed in the

national survey. That is, girls would show advancement during their pubescence but later the

mean differences would decrease rapidly when

the boys became pubescent.

There is nu clear evidence in the previous

literature that a spurt occurs in skeletal maturation during pubescence but there is reason

to believe this is so. Roche 97 reported findings

obtained by assessing the female standards in

one copy of several standard atlases against

the male standards in another copy. The findings

showed an increase and subsequent decrease

in these differences for the hand-wrist at about

the time of puberty using eithe~-r the GreulichPyle 27 or Tanner-Whitehouse method, but

there were no corresponding changes in these

differences during pubescence for the knee37

or foot-ankle. lW Using data from a smalI group

of children and youths, Todd 96 reported sexassociated differences in skeletal maturity levels

for the hand-wrist, knee, and elbow that support

the view that a pubescent spurt occurs. Evidence of a pubertal spurt in the maturation of

the hip joint w has been reported also. It is

well known that testosterone and estrogens,

when given to boys or girls,. ~:::ozmarkedly

accelerate skeletal maturation. ‘ Consequently, the occurrence of a pubescent spurt

in skeletal maturation, associated with increased

levels of circulating steroids, is biologically reasonable.

Another feature of interest in the national

survey data concerns the mean differences between skeletal and chronological age in the

girls when female equivalent values are used.

The mean differences between boys and girls

(female equivalent values for the latter) in

“skeletal age less chronological age” are comparatively small until 13.5 years. Later there

is a rapid increase in these mean differences

until the difference is 19.4 months at 17.5 years.

It is important to note that an average of only

3.4 bones in each hand-wrist could be assessed

in the girls at 17.5 years and that all the bones

of the hand-wrist had become adult in 22 percent

of the girls at that age. Nevertheless, the findings

are not entirely due to the exclusion of hand-wrist

32 -

24 –

16 -

s _ ,... Pyle etal. (1971 )

—— United States, 1963.70

06~8

CHRONOLOGICAL AGE [N YEARS

Figure 18. Mean differences between boys and girls in skeletal

age (hand-wrist) on the male l-tES standard for the United

States children and youths from the national studies

(1963-70) and from data of Greulich and Pyle by chronological age.

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— United States,1903.70

Figure 19. Meen differences between boys and girls in selected bone-specific skeletal ageson the male HES standard for United States

children and youths from the national studies (1963-70) and from data of Greulich and Pyle by chronological age.

bones that had become adult or of girls in whom

all these bones had become adult.

To some extent, these findings reflect problems with the method of transformation from

male skeletal ages to female equivalent values

as the end of the skeletal maturity scale is

approached. These problems are real, but their

importance should not be overemphasized. They

occur only near the end of maturation when

application of the skeletal maturity scale is less

important clinically. Comparisons between the

skeletal ages for boys and the

values for the girls indicate

40

female equivalent

a sex-associated

increase in the mean sex differences in skeletal

maturity levels from 10.5 to 12.5 years and then

a decrease to 17.5 years. However, this decrease

appears to be too slight as the end of the scale

is approached. The difficulty becomes apparent

when boys begin to have pubescent spurts and

when substantial numbers of bones in the girls

become adult and therefore, for the reasons

given earlier, are not used in calculating means.

The problems encountered with the female equivalent values, towards the end of the scale, are

associated with the truncation of the distributions

of skeletal ages within older age groups. The

. .
difficulties are, of course, not due to a marked

acceleration of the Cleveland group of older

youths; this would have been reflected in the

findings for both boys and girls. Due to doubts

about the accuracy of the female equivalent

values towards the end of the skeletal maturity

scale only, the emphasis in this discussion is

on the original data obtained by assessment

against the male standard for both sexes. The

decision, made long ago, to assess against a

single standard has introduced difficulties of

interpretation but it has allowed a remarkably

objective measure of sex differences and has

provided new insights regarding the nature of

the skeletal maturity scale.

When previous data for mean skeletal ages

in United States youths are compared with the

present national survey findings, it is noted

that the levels for boys in the ~~dd Atlas M

and those reported by Simmons are closer

to the present levels than those in the GreulichPyle Atlas. 27 Those of Flory 61 and Maresh 65

are markedly lower at most ages, while those

of Johnston 63 are higher. Comparisons for girls

are more tentative because they can be made

only by using the female equivalent values and,

towards the end of the maturity scale, there

is doubt about the accuracy of these transformations.

Variability of Means

When variability is expressed as the coefficient of variation, the pattern of change *

age is similar in both sexes for the period

6-17 years. Increases in variability associated

with pubescence thus imply the existence of

a pubescent spurt in skeletal maturation. These

occur about 2 years earlier in the girls than the

boys. Boys are more variable than girls throughout the whole 12-17 range. This is due, in part,

to the later occurrence of pubescence in boys

and to the fact that the distribution of girls

becomes truncated as the adult end of the skeletal maturity scale is approached. In younger

children (6-7 years) also, the coefficient of

variation is greater in boys than girls. At these

ages it is probable that this difference reflects

th~ higher incidence, in boys than in girls, of

bones that have just become radio-opaque. It

is well known that the timing of this phase of

skeletal maturation is very variable.27

In the national survey, the distributions of

skeletal age, within chronological age groups,

were near normal except at older ages when

the distributions tended to be skewed to the right

particularly in girls. This effect was more marked

in the girls because more of them reached the

maximum values. Comparisons with previously

reported data are of limited value because the

groups studied by others were relatively small.

The standard deviations from the national

survey are higher than those reported by others

for groups of United States boys at 12-14 years,

Later there is a more marked decrease in variability in the national survey data than in

those reported by others. In the girls (female

equivalent values), however, the standard deviations are, with one exception, lower than

those reported previously for groups of United

States youths. It is not clear why variability

differs’ among the studies in ways that are not

the same for both sexes. It is also puzzling

to find that the national survey data indicate

that variability is more marked in boys than

girls, whereas the opposite has been reported

by others. Differences in methodology (the present

assessors did not know the age or sex of the

youths and all youths were assessed against

male standards) may have been a factor. Also,

it should be recalled that the national sample

was large and the reliability of the assessments

was particularly high.

Bone-Specific Skeletal Ages

This national survey has provided reference

data for the skeletal ages of each hand-wrist

bone in U.S. youths 12-17 years. For almost

every bone, the mean skeletal age increases

with increasing chronological age, but the annual

increments tend to decrease, partly because

adult bones did not have skeletal ages assigned

to them. These bones have been excluded from

the analysis. This pattern of smaller annual

increments at older ages is absent for the later

ossifying bones (adductor sesamoid in boys;

flexor sesamoid in each sex). Except for these

bones, the patterns of change across age in the

three skeletal ages (males and females assessed

41
as males, female equivalent values) for each

bone are generally similar to those for the mean

skeletal age of the hand-wrist.

The bone-specific skeletal ages obtained

in the national survey allow a judgment about

the applicability of the Greulich-P yle Atlas standards to the whole United States population. In

addition, these ages will assist the recognition

of clinical conditions in which maturation is

dysharmonic. 103-105 Despite the need for normative data concerning bone-specific skeletal

ages, these were not available for United States

youths, nor are such data available for the youths

of any other country.

It is preferable to consider the sex differences in skeletal maturity for individual bones

using assessments for each sex against the

same set of male standards. In the earlier study

of children, 1 these sex differences tended to

increase with age for almost all the bones. In

the youths, they decrease gradually with increasing age. It is considered that much of

this decrease is real, for reasons that have

been discussed fully in regard to mean skeletal age.

The variability of these bone-specific skeletal ages tended to decrease with age and was

generally greater in boys than girls. The low

variability of the adductor and flexor sesamoids

in boys at 12 years reflects the fact that, in

most boys, these sesamoids would have just

ossified. The variability y of these bone-specific

skeletal maturity levels, across age, was influenced by the exclusion of bones that had

become adult to such an extent that the standard

deviations are less than 1 month for nine bones

in the girls at 17 years. Variability is low also

for bones that had just become radio-opaque

in girls at 12 years. In general, the standard

deviations for girls range from 12-15 months.

In the boys they range from 16-18 months.

Reference data have not been reported previously concerning the range of bone-specific

skeletal ages within the hand-wrist areas of individual United States youths. It has been claimed

that the skeleton of the healthy adequately nourished child develops as a unit and its bones

differ little in skeletal maturity levels. X One

purpose of the present national survey was to

determine the extent to which this statement

is correct for the whole population of United

States youths. Others have suggested that the

range from the least mature to the most mature

bone varies directly with the difference between

hand-wrist skeletal age and chronological age~~

but convincing proof has not been reported.

Pyle et al.lw graphed the extreme bone-specific

skeletal ages for each radiograph against chronological age, in addition to the mean skeletal

age, and claimed that the most mature bonespecific age indicates the youth’s potential for

skeletal maturation level. Application of this

method would assign, to almost all youths, a

potential well in advance of the Greulich-Pyle

standards: This attitude of Pyle et al~~

accords, however, with Todd’s M statement that

in assessment one should utilize the most advanced centers, not the average of all. Few have

followed the suggestion of Pyle et al~M because

reference data are lacking and because the

usefulness of these graphs has not been demonstrated.

The bone- specfiic skeletal ages that were

obtained in the national survey allowed calculation of the range of these ages within each

hand-wrist. These ranges are necessarily truncated, particularly in older girls, by the exclusion of bones that had become adult. This

could be largely responsible for the finding

that the median ranges tend to be larger in the

boys (table 9). However, the communality indices

of ages at onset of ossification in the primary

centers during prenatal life and in the epiphyses

during infancy and childhood are higher in girls

than boys. 39,107,108Clearly the range is a function

of the possible spread on the scale and the number of bones assessed, in addition to biological

factors. Although the median ranges are greater

in boys, the variability of these ranges is greater

in girls at all ages. With increasing age, there

is a tendency for variability to increase and for

the sex differences in variability to increase.

What factors were responsible for these changes

in the variability of these ranges are not understood.

Many workers assign bone-specific skeletal

ages before combining these to obtain a single

skeletal age for each hand- wrist area. This

combination is necessary because in almost

every child or youth the hand-wrist bones differ

42

>
in skeletal age. These differences are partly

38,109-lllThey are not due genetically determined.

entirely to the effects of illness and other environmental factors that were emphasized by

Todd.M Largely because of the attitude of

Todd,M it has been suggested that the bones

within a hand-wrist with aberrant maturity levels

should be ignored. 72 Others have claimed that

dysharmonic bones should be recorded on the

assumption that they can provide data about the

normality of the previous nutrition and illness

history of the child.lM

Various combinations of the same bonespecific skeletal ages yield different area skeletal ages, either for individuals or groups.112

However, it is not known which is the best

method of combining these bone-specific skeletal ages. One particularly difficult problem

concerns the occurrence of familial late ossification of particular centers, without retardation in other centers. 113The problem of combining bone-specific skeletal ages to a single

value becomes particularly difficult at each

end of the scale. This occurs because skeletal

ages, expressed in years, cannot be assigned

to centers that are not yet radio-opaque or are

already adult. The aim of combining bonespecific skeletal ages should be to describe the

data parsimoniously. Pragmatically, the best

combination is the one that works best, but this

may vary with the purpose and with the youths

studied. Such an approach is likely to add further

confusion to a biological area that does not

need it.

It has been claimed that the carpals should

be excluded because they reach adult levels

of maturity before most other bones.61’ 114’115

Furthermore, th;ir inclusion reduces the replicability of overall but not bone-specific assessments~”’ 115’116Certainly, it seems unacceptable to assign skeletal ages co carpals on the

basis suggested by Tanner}17 i.e., to view the

hand as a whole and when epiphyseal closure

is underway to deduce that the carpal bones

are adult and rate them accordingly. Some consider the carpals should be omitted because

their maturity levels vary widely within chronological age groups, ” 39’107 but variability is

desirable. Its absence would make assessments

unnecessary.

Onset of Ossification

Data recorded between 12 and 17 years are

suitable for determining the age of onset of ossif ication of the adductor and flexor sesamoids

in boys and the flexor sesamoid in girls. These

ages from ‘the national survey data are slightly

later than those reported by Greulich and Pyle 27

for the flexor sesamoid in boys, but they are

earlier than the Greulich- Pyle estimate for the

adductor sesamoid. In girls, they are markedly

later for the flexor sesamoid.

Epiphyseal Fusion

Median ages for the completion of epiphyseal

fusion in the radius, ulna, and each short bone

of the hand were calculated from the national

survey data. These ages from the Health Examination Survey were later in boys (15.6 to

16.6 years) than in girls (13.4 to 14.9) when

the radius and ulna were excluded. Sex comparisons were not possible for the latter two

bones. In general, the order of fusion was

distal phalanges, proximal and middle phalanges,

metacarpal, radius, and ulna, which is in agreement with the order from previous studies.

However, some bones, particularly metacarpal I,

fused earlier than other bones in the same row.

There is a tendency for these ages to be slightly

earlier than those reported by Garn et al.91

Youths Also Examined

as Children

About one-third (2,177) of the youths in the

present survey had been examined earlier in

the survey of children. These serial data, obtained using the same methodology in both surveys, show that increases in skeletal age that

were less than the changes in chronological

age were more common in the boys than the

girls. The opposite changes (increases in skeletal ages greater than those in chronological

age) were more common in the girls.

The distributions of the differences between

skeletal age and chronological age (skeletal age

less chronological age) changed between the two

examinations. More youths, both male and female, were markedly advanced in skeletal ma43
turity at the second than at the first examination.

This reflects the patterns of change in the complete

samples during the 4-year period considered.

The skeletal maturity scale against which the

radiographs were assessed is much too high

for the total United States population aged 7

to 11 years, but it is only slightly too high

for youths aged 11 to 15 years.

Conclusion

The skeletal maturity levels provided in

this report are useful to a wide variety of

health-related professions.. Pediatricians use

skeletal age in the recognition “of, ‘syndromes

afid in the diagnosis and management of youths

who are growing at unusual “rates. Pediatric

surgeons need skeletal age assessments to monitor the effects of some procedures, e.g.,

cardiac surgery, and to plan some operations,

especially those designed to equalize leg length.

Skeletal age assessments are important also

for those (speech therapists, orthodontists,

craniofacial surgeons) who work with youths

in whom the length of the cranial base may

be abnormal. Nutritionists and human biologists need skeletal age assessments both to

describe populations and to analyze the associations between skeletal maturation and skeletal elongation.

For the first time, each of these groups now

has available national estimates for skeletal maturit y levels both for the hand-wrist and for each

of its constituent bones in U.S. youths aged 12

to 17 years.

SUMMARY

The data in this report were obtained during

the examination, from 1966 to 1970, of a national

probability sample of United States youths aged

12-17 years. The 7,514 youths selected in the

sample were representative of the 22.7 million

noninstitutionalized youths, in the same age

range, in the United States. The sample examined

included 6,768 of these youths, or 90 percent

of those selected. National estimates for the variables considered could be obtained because

the data from each youth were weighted dif -

ferentially depending on the part of the total

population of youths that he represented.

A radiograph was taken of the right handwrist of each youth. These radiographs were

assessed by medical students who received special training in the assessment of skeletal maturity and whose levels of reliability were high

when applying these techniques. When making

these assessments, the students did not know the

age or sex of any youth. Consequently, several

potential sources of bias were absent from the

data. AU the assessments were made against

a single set of maturity. standards for males

that was prepared for the” survey by Dr. S.1,

Pyle. Later, the values ‘for girls were transformed, for each bone separately, to female

equivalent values using the sex-associated differences reported by Pyle et al. 8

As expected, when all the youths are assessed against the same set of male standards,

the skeletal ages of the girls tend to be more

advanced than those of the boys. The mean

values for boys are less than the chronological

ages for most of the age range 12-17, but the

differences between the mean skeletal and chronological ages decrease as chronological age

advances. These age related changes show that

the scale of maturity used was imperfect when

applied to a national probability sample of U.S.

boys. The mean skeletal ages for the girls exceed the chronological ages by 24.9 months

at 12 years, but this advancement decreases

with increasing age until it is only 1.5 months

at 17 years.

The differences between the mean skeletal

and chronological ages show pubertal accelerations in each sex, with the maximum advancement at 15,5 years in boys and 12.5 years

in girls. The spurt in the girls, assessed as

boys, becomes even more marked if adjustments

are made for the failure of the set of male

standards to match this sample of youths in

mean skeletal maturity levels. These findings

confirm earlier reports that a pubertal spurt

occurs in skeletal maturation. Also they direct

attention to another problem with the scale

of maturity. Not only is the scale set too high

for boys, it is not precise in its scaling because,

if the scale were ideal, a spurt would not be

apparent in cross-sectional data.

44
When the data for the girls are transformed

to female equivalent values, the mean sex differences are comparatively small to 13.5 years,

but later they increase rapidly to reach 25.5

months at 17 years, with the values for the

girls being less than those for the boys. This

rapid increase in the differences between the

sexes is not due entirely to the more common

exclusion of adult bones among girls than among

boys. Partly it reflects problems with the method

of obtaining the female equivalent values near

the adult end of the skeletal maturity scale.

Due to this problem with the transformation of

data, most of the conclusions in this report are

based on data for both sexes assessed against

the same male standards. These findings have

been compared with data reported previously.

When these comparisons are evaluated, it is

difficult to overemphasize one major difference

between this and previous studies. The earlier

investigations have been of comparatively small

groups of youths chosen on a basis of convenience

rather than by rigorous sampling procedures.

Consequently, the findings from them are less

reliable and generalizations from them to the

total U.S. population of youths ip fraught with

danger.

From 12 to 17 years, skeletal age was more

variable in boys than in girls, partly because

of the later occurrence of pubescence in boys

and partly because the distributions become

truncated in girls near the end of the scale.

The variability of skeletal age, within chronological age groups, increases during the pubescent spurt in each sex. Presumably, this is

associated with variations among individuals

in the magnitude and timing of the spurt.

The mean skeletal ages, within chronological age groups, were distributed in an almost

normal fashion except in older girls, where

the right ends of the distributions were truncated

because the hand-wrists of some of the girls

had become adult. In general, the standard

deviations of the means from the national survey data are lower than those reported by

others and lower for girls than for boys. These

sex differences are in the opposite direction

to those reported by others.

Reference data are provided for bone- specific skeletal ages from 12 to 17 years. These

increase with chronological age but the annual

increments tend to become smaller as 17 years

is approached. The ranges of these ages, within

individual hand- wrists, tend to be larger in the

boys but the ranges themselves are more variable in the girls.

There are only three hand-wrist bones (both

sexes combined) that typically have their onsets

of ossification during the age range of the present survey. The national estimates of these

ages for the adductor sesamoid (boys) and the

flexor sesamoid (boys) are in good general

agreement with data from other studies.. The

estimated age at onset of ossification in the

flexor sesamoid in girls is, however, markedly

later in the national survey data than the only

value reported previously for a group of United

States girls. m

Epiphyseal Fusion

The Health Examination Survey data allowed

the estimation of median ages for epiphyseal

fusion for all the short bones of the hand and

for the ulna in girls. The order in which fusion

occurred closely matched that reported previously. The ages from the present national

study tend to be slightly earIier than those of

Garn et al.91 who are the only previous workers to have studied a large group of children

in this country. Data from the national survey

are in general agreement with those reported

from earlier studies of groups of youths in

this country. The mean order of fusion for rows

of bones is the same in each sex: distal phalanges, proximal phalanges, middle phalanges,

metacarpal, radius, and ulna. However, metacarpal I fuses early relative to the other

bone in the same row. The median sex difference in the timing of fusion is 2.2 years.

Youths Also Examined as Children

Data from more than 2,000 of the youths

who were examined also as children are consistent

with the cross- sectional data from the total

samples. The serial changes in the recorded

skeletal ages are influenced by the patterns

of changes across age in the differences between

the skeletal age equivalents of the standards

45
against which the radiographs were assessed maturity in United States youths. This extends

and the actual maturity levels of the United the age range of the previous survey of chilStates population. drenl and, together with the Health Examination

As a result of this survey, national estimates Survey findings of 1963-65, provides reference

are available for many aspects of hand-wrist data for the age range 6-17 years,

000

44
REFERENCES

1

National Center for Health Statistics: Skeletal

maturity of children 6-11 years, United States. 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.

2

National Center for Health Statistics: Skeletal

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3

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7

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A

8

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. . .

49
78 Michelson, N.: A method for assessing the

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82 Hepworth, S. M.: On the determination of age in

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87 Flecker, H.: Time of appearance and fusion of

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88 Paterson, R. S.: A radiological investigation of the

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90 Narayan, D., and Bajaj, J. D.: Ages of epiphyseal

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92 Russell W. J., Keehn, R. J., Ihno, Y., Hatturi, F.,

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children exposed to

108:367-374, 1973.

50

the A-bomb in utero. Radiology.

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94 Vandervae1, F.: Cnteres d’estimation de I’age des

squelettes entre 18 et 38 ans. S. A. S. BoIL Comitato

intemaz., per l’unific. dei metodi e per 1a sinteni in

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changes in young American males analyzed from tile

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96 Todd T. W.: Differential skeletzd maturation in

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97 Roche, A. F.: Sex-associated differences in skeletal

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9 ‘Tanner, J. M., Whitehouse, R. H., and HeaJy, M. J.

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Radio~aphic Atlas of Skeletal Development of the Foot

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101 Kaplan, S. A.: Growth Disorders in Children and

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102 WettenhaH, H. N. B., and Roche, A. F.: Tall girls

assessment and management. Aust. Paed. J. 1:210-216,

1965.

103Jones, P. R. M., and Dean, R. F. A.: Effects of

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104Mass6, G., and Hunt, Jr., E. E.,: Skeletal

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107 Garn, S. M., and Rohmann, C. G.: Communalities

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108Burdi, A. R., Garn, S. M., and Babler, W. J.:

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National Center for Health Statistics: Quality

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132

Hansman, C. F., and Maresh, M. M.: A

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51
LIST OF DETAILED TABLES

Table 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

Meen, standard deviation (.X),end standard error of mean (.x) for skeletal age

@~d~st) of youths, by chronological age in years at last birthday and sex;

standard deviation for skeletal age (hand-wrist) of youths within 6-

month chronological age intervals by sex, and number of youths at each chronological age by sex: United States, 1966-70--------------------------------------

Meen end standard deviation for skeletal age (hand-wrist) of youths, by chronological age in months end sex: United States, 1966-70---------------------------

Percent distribution and selected percentiles for skeletal age (hand-wrist) of

youths, by chronological age in years at last birthday end sex: United States,

1966-70-------------------------------------------------------------------------

Percent distribution and selected percentiles for skeletal age (hand-wrist) in

months of youths, by chronological age at last birthday in 6-month intervals end

sex: United States, 1966-70-----------------------------------------------------

Percent of youths showing the number of radio-opaque hand-wrist bones—ossifying

and adult—by chronological age in yearsat last birthday end sex: United States,

1966-70-------------------------------------------------------------------------

Mean, standard deviation (s,),and standard error of mean (.X) bone-specific

skeletal ages for the 31 individual hand-wrist bones of youths end the number of

yo:;h~h by chronological age in years at last birthday end sex: United States,

-------------------------------------------------------------------------

Mean and standard deviation (sX)ofbone-specific skeletal ages for selected handwrist bones of youths, by chronological age in 6-month intervals and sex: United

States, 1966-70-----------------------------------------------------------------

Selected percentiles in the distribution of bone-specific skeletal ages for each

of the 31 hand-wrist bones of youths, by chronological age in years at last

birthday end sex: United States, 1966-70----------------------------------------

Selected percentiles, mean and standard deviations (s.) 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 chronological age in years at

last birthday and sex: United States, 1966-70-----------------------------------

Median age in months atepiphyseal fusion for selected hand-wrist bones of youths

12-17 years chronological age at last birthday by sex: United States, 1966-70---

Selected skeletal maturity findings for children age 6-11 years in 1963-65 who

were again examined as youths age 12-17 years in 1966-70 (32 percentof the youth

examiners): United States, 1963-70----------------------------------------------

Percent distribution of increase in skeletal maturation (hand-wrist) between

first and second examination within designated time intervals between the two

examinations for boys and girls in both the Health Examination Surveys of 1963-

65 end 1966-70------------------------------------------------------------------

Percent distribution of the lagof skeletal age (hand-wrist) behind chronological

age at the time of the first and second examination for boys and girls in both

the Health Examination Surveys of 1963-65 and 1966-70---------------------------

Page

54

55

56

58

61

64

71

74

78

79

80

82

83

53
Table 1. Mean, standard deviation (sx), and standard error of mean (si) for skeletal age (hand-wrist)

of youths, by chronological age in years at last birthday and sex; mean and standard deviation for

skeletal age (hand-wrist)of youths within 6-month chronological age intervals by sex, and number of

youtha at each chronological age by sex: United Statea, 1966-70

Chronological age

at last birthday

Age in years

12

13

14

15

16

17

years------------------

years------------------

years------------------

years------------------

years------------------

years------------------

Age in 6-month intervals

12 years:

‘ O-5 months--------------

6-11 months-------------

13 years:

O-5 months--------------

6-11 months-------------

M years:

O-5 months--------------

6-11 months-------------

15 years:

O-5 months--------------

6-11 months-------------

16 years:

O-5 months--------------

6-11 months-------------

17 years:

0-5 months--------------

6-11 months-------------

Boys (male Girls (male Girls (female

standard) standard) equivalent)

Mean Sx SF Mean Sx s? Mean Sx s=

Skeletal age (hand-wrist)in months

140.2

157.4

173.6

186.5

196.4

205.4

134.4

145.0

153.1

162.3

171.7

175,5

183.7

189.5

193.7

199.5

204.7

206.2

17.02

18.05

15.12

14.29

13.81

11.08

16.08

16.26

1?.15

16.60

14.91

15.09

14.75

13.12

13.78

13.17

11.09

11.00

0.65

0.86

0.75

0.61

0.74

0.48

0.98

1.04

1.18

0.96

0.87

1.13

0.93

0.83

1.02

0.96

0.69

0.96

174.9

186.6’

198.0

205.6

211.3

211.5

171.6

177.9

183.2

190.4

195.6

200.6

204.6

206.5

210.3

212.4

210.9

212.2

L4.84 0.69

12.97 0.62

10.82 0.60

9.16 0.49

9.95 0.48

9.95.0.61

14.01 1.13

14.92 0.91

12.66 0.96

12.25 0.94

11.12 0.89

9.84 0.66

9.02 0.88

9.20 0.36

9.46 0.87

1.O.360.60

9.07 0.75

LO.84 0.87

142.9

155:2

168.0

177.6

185.6

186.0

139.6

145.9

151.2

159.4

165.6

171.6

176.2

178.5

184.3

187.8

184.9

187.4

12.12 0.56

10.79 0.52

9.18 0.51

7.91 0.42

8.74 0.42

8.75 0.54

11.40 0.92

12.24 0.75

10.45 0.79

10.26 0.79

9.41 0.75

8.42 0.56

7.77 0.76

7.95 0.31

8.29 0.76

9.16 0.53

7.95 0.66

9.57 0.77

Population with

ossifying bones

E

Number in

thousands

2,024

2,003

1,948

1,883

1,792

1,574

908

1,117

1,072

931

971

977

976

907

980

812

825

748

1,953

1,943

1,881

1,774

1,565

1,344

928

1,025

1,026

917

974

907

856

918

825

740

722

622

54
Table 2. Mean and standard deviation for skeletal age (hand-wrist) of youths, by chronological age in months and

sex: United States, 1966-70

Chronological age at’

last birthday and sex

Months of chronological age (after last birthday)

o 1 2 3 4 5 6 7 8 9 10 11

Bovs (male standard) Mean skeletal age (hand-wrist) in months

134.8

145.6

168.8

181.2

194.6

204.9

191.3

173.8

181.2

195.9

203.4

207.6

212.6

206.0

141.8

149.2

165.9

174.4

180.21

188.2

178.0’

134.4

160.5

171.5

182.8

195.2

208.1

...

172.9

185.5

195.1

206.1

214.1

213.1

...

140.9

153.5

165.1

178.1

190.1

189.1

...

135.5

156.1

174.9

186.4

196.9

205.6

142.3

160.3

175.1

187.5

197.6

205.9

140.0 144.2 146.4

159.9 164.0 162.7

168.6 173.5 178.1

187.5 191.0 188.1

194.6 201.7 201.0

206.3 203.7 209.4

12

13

14

15

16

17

18

12

13

14

15

16

17

18

121.9

146.2

169.4

177.7

190.0

201.4

208.1

158.8

180.0

194.9

204.8

207.0

211.4

209.0

129.4

148.0

164.8

176.6

179.0

185.8

182.0

5.92

19.16

12.80

16.18

15.45

12.19

8.87

18.96

11.53

11.45

8.58

10.27

7.46

15.85

138.C

157.1

172.1

183.8

190.C

202.0

...

168.6

182.5

196.6

207.7

209.8

209.4

...

136.6

150.5

166.6

180.4

183.6

X82.8

...

130.L

152.8

172.5

188.8

196.4

205.3

...

169.7

185.1

194.1

202.6

212.3

207.9

...

137.7

153.1

163.2

173.6

187.6

180.8

...

148.6

162.4

173.3

188.3

199.9

208.0

...

183.1

192.2

199.2

207.6

213.8

211.6

...

151.1

161.2

170.2

180.2

189.8

186.2

...

147.5

164.8

182.0

195.0

204.2

204.5

...

176.7

192.1

202.1

208.4

213.7

214.9

...

144.7

161.1

173.1

181.4

189.7

190.9

...

14.49

i2.58

14.38

10.38

9.59

9.60

...

12.98

11.26.

10.17

9.06

8.26

8.18

...

years --------------------

years--------------------

years--------------------

years--------------------

years--------------------

years--------------------

years-------------------- . . . . . . . . . . . . . . .

Girls (male standard)

174.6 173.2

185.9 186.5

197.5 201.5

204.0 203.9

214.1 209.3

211.1 210.9

175.7 181.4 177.6

191.2 191.0 190.7

200.9 199.8 200.6

204.5 206.7 208.3

211.7 212.8 212.4

211.7 212.5 218.2

years --------------------

years --------------------

years --------------------

years--------------------

years--------------------

years--------------------

years-------------------- . . . . . . . . .

143.7

160.2

171.9

176.0

186.4

186.4

...

. . . . . .

Girls (female equivalent)

12 years --------------------

13 years--------------------

14 years--------------------

15 years --------------------

16 years--------------------

17 years--------------------

18 years--------------------

142.6 141.2

153.9 155.0

i67.5 172.5

175.0 174.9

190.1 182.6

185.2 184.9

149.4 145.6

160.0 159.7

170.8 171.6

178.7 181.3

188.6 187.8

188.0 194.4

. . . . . . . . . . . .

Boys (male standard) Standard deviation in skeletal age (hand-wrist) in months

12 years--------------------

13 years--------------------

14 years--------------------

15 years--------------------

16 years--------------------

17 years--------------------

18 years--------------------

16.91 17.26

17.89 17.98

16.64 13.16

13.33 15.79

14.71 14.45

11.29 12.12

13.06

17.30

15.28

12.23

11.57

9.63

...

14.07

13.04

13.83

9.99

8.63

9.72

...

15.33

14.55

17.20

14.44

11.68

9.94

...

11.95

11.45

10.09

7.60

6.57

8.23

...

16.34

16.84

11.73

13.57

11.51

10.08

...

13.00

11.64

8.97

10.85

8.27

9.75

...

15.75

16.57

12.69

12.14

13.77

9.44

...

16.14

11.87

8.47

8.46

10.51

9.68

...

15.34

17.49

15.07

11.84

12.80

7.30

...

15.11

11.63

10.88

9.23

7.64

12.04

...

16.16

16.26

18.19

13.82

15.00

15.28

...

14.31

12.17

10.23

8.47

16.20

10.97

...

16.61

15.49

13.16

11.66

12.64

8.89

16.73

19.05

12.36

16.59

13.20

10.64

11 . . . . . . . . .

Girls (male standard)

14.21 14.49

15.02 10.97

10.89 9.19

7.58 8.71

9.92 9.04

8.04 9.87

12 years --------------------

13 years--------------------

14 years --------------------

15 years--------------------

16 years--------------------

17 years--------------------

18 years--------------------

15.77

13.33

9.05

9.25

8.17

3.73

13.27

11.71

9.67

9.88

7.22

10.54

-1 ...

. . . . . .

55
Table 3. Percent distributionand selected percentiles for skeletal age (hand-wrist)

of youths, by chronologicalage in years at last birthday and sex: United States,

1966-70

Skeletal age (hand-wrist)

in months

Below 901----------------------------

90-95--------------------------------

96-101-------------------------------

102-107------------------------------

108-113------------------------------

114-119------------------------------

120-125------------------------------

126-131------------------------------

132-137------------------------------

138-143------------------------------

144-149----------------.-------------

150-155------------------------------

156-161------------------------------

162-167------------------------------

168-173------------------------------

174-179------------------------------

180-185------------------------------

186-191------------------------------

192-197------------------------------

198-203------------------------------

204-209------------------------------

210-215------------------------------

216-221------------------------------

222-223------------------------------

Percentile

Pg5 -------- -------- ------------------

P75 ------------------------ -------- --

-PR O----------------------------------

P25 ------- ------- ------- ------- ------

P5 -------- -------- -------- -------- --

Boys—chronological age in years

12 13 14 15 16 17

Percent distribution—male standard

0.1

0.1

:.;

2:8

1::+

14.7

11.2

1:::

10.6

9.5

6.5

3.5

1.1

0.4

0.1

0.;

2.0

M

4.3

6.3

1:::

12.7

14.3

13.4

9.4

;.:

●

::!?

0.1

0.;

0.;

0.4

0.6

1.8

M

10.0

10.9

17.9

20.0

l;.:

.

::;

M

O.i

0.2

0.:

:::

5.4

1?::

15.0

8.9

15.4

12.7

;.;

0:8

0.2

-

0.;

o.i

0.5

1.2

$;

R

10.4

15.0

22.4

18.2

8.4

3.1

2.2

Skeletal age (hand-wrist)in months

168.3

154.4

139.4

127.2

115.5

lLowestvalue 89 months - boys aged 12 years.

I owM_- 183.3

170.6

158.9

145.2

123.5

199.6

182.1

174.0

165.0

147.5

-

-

-

-

0.;

-

.

-

.

N

2.2

;:;

1;::

20.4

21.3

11.7 6.?

223.1

212.E

206.5

199.3

186.:

56
Table 3. Percent distributionand selected percentiles for skeletal age (hand-wrist)

Of youths, by chronologicalage in years at last birthday and sex: United States,

1966-70—Con.

Girls—chronological age in years

12 13 14 15 16 17

Percent distribution—male standard

.-

O.i

0.;

1.3

1.2

1.9

:::

10.8

17.5

20.6

12.1

:::

2.8

1.0

0.7

0.1

197.8

184.5

175.2

166,7

150.0

0.;

;.;

10;2

16.5

14.0

13.3

17.9

12.2

6.5

1.9

0.5

207.2

196.8

187.3

177.3

166.1

0.;

0.;

0.6

::;

5.0

7.0

23.4

25.7

19.9

8.1

;:;

212.9

205.1

199.4

193.4

176.7

0.1

0.2

1.7

3.4

16.5

17.4

25.6

20.6

M

Ske-

.

o.i

0.;

0.4

0.8

J:;

16.0

25.8

18.5

19.3

0.;

0.;

1.1

1.1

1;:;

13.8

25.5

16.8

22.7

Girls-chronological age in years –

12 13 14 15 16 17

Percent distribution-female equivalent

::;

0.3

$!

12.7

15.4

18.0

1:.;

9:0

6.6

2.2

1.6

0.7

0.1

0.;

H

11.9

17.7

12::

15.3

10.6

6.0

;::

0.5

0.;

t;

2.7

5.4

4.5

2::?

21.4

19.0

10.2

3.2

;:;

.etalage (hand-wrist)in months

223,0 223.7 223.8 167.8 179.4 188.8

212.0 220.3 220.7 152.5 166.8 177.1

206.1 212.1 212.9 143● 2 156.3 170.4

199.2 206.4 205.1 134.7 145.3 162.4

191.5 195.4 194.4 124.0 134.1 144.7

o.i

0.;

2*2

12::

14.3

21.2

17.4

10.7

;:;

201.0

187.0

178.1

;::.;

●

0.1

0.;

M

6.6

9.4

2;:;

12.7

18.4

19.6

201.7

197.3

186.2

178.4

164.8

0.;

0.;

0.9

M

1;::

10.2

13.7

15.8

16.5

23.2

201.8

197.7

186.9

176.2

163.4

57
Table 4. Percent distributionand 8electedpercentilesfor skeletalage (hand-wrist)in months of youths, by chronological age

at last birthday in 6-month intervals and sex: United States, 1966-70

Boys—chronological age in months

Skeletal age

(ha&d:tm:::) 210

144-149 150-155 156-161 162-167 168-173 174-179 180-185 186-191 192-197 19S-203 204-209 or

more

Below 90----------

90-95-------------

96-101------------

102-107-----------

los-l13-----------

114-119-----------

120-125-----------

126-131-----=-----

132-137-----------

138-143-----------

u4-149-----------

150-155-----------

156-161-----------

162-167-----------

168-173-----------

174-179-----------

180-185-----------

186-191-----------

192-197-----------

198-203-----------

204-209-----------

210-215-----------

216-221-----------

222-223-----------

Percentile I

P,5 ---------------

P~----------------

P*5---------------

0.3

0.3

0.3

0.7

5.2

11.s

14.1

19.1

11.4

7.7

10,8

7.1

6.0

1.7

2.5

0.8

0.2

145.3

131.5

121.5

.

0.3

0.9

5.1

7.9

10.9

10.9

10.9

10.2

13.4

12.5

10.5

4.3

1.4

0.8

-

.

1.5

3.4

3.6

6.7

5.8

9.0

9.1

12.7

13.1

12.1

11.9

7.5

1.7

0.s

0.9

.

0,2

157.8 166.5

145.3 155.4

131.9 142.0

Percent distribution-male standard

-

0.3 .

3.2 0.3

3.7 0.7

2.5 0.6

3,2 2.4

6,S 3.4

11.5 5.8

12.5 12.1

16.6 11.7

15,0 18.0

11.6 19.6

8.8 12.4

2.5 3.s

1.2 3.1

0.3 4.3

0.3 1.4

0.4

.

-

-

0.7

0.5

1.3

1.3

5.4

8.0

9.9

17.8

20.6

10.3

8.4

9.1

4.2

2.3

0,2

-

.

0.3

1.2

1.6

2.9

7.7

11.4

20.2

13.6

5.7

13.4

13.s

6.8

0.9

0.2

0.3

-

0.2

-

0.4

0.2

0.3 0.3

0.9 1.s

3.0 3.3

6.4 4.1

14.3 5.3

16.5 8.1

12.5 11.9

17.4 19.4

11.6 22.7

13.3 14.6

2.1 5.6

1.5 0.8

1.5

Skeletal age (hand-wriet) in months

173.9 180.1 185.2

165.3 172.3 175.s

152.7 161.8 167.1

197.2

1S1.6

173.9

199.5 203.3

190.0 196.3

179.9 186.8

0.4

0.6

2.4

10.1

2.8

S.6

9.7

22.3

22.5

11.7

5.9

3.0

208,9

202.1

192.0

-

-

-

-

0.2

0.3

2,9

3.5

7.0

10.3

19.7

18.3

19.4

12.5

5.9

212.6

205.9

198.6

.

0.4

.

1.5

0.8

4.6

9.4

19.6

22,8 .

23.4

10.s

6.7

213.2

207.4

199.9
*

Table 4. Percent distributionand selectedpercentilesfor skeletalage (hand-wrist)in months of youths, by chromlogical age

at last birthday in 6-month intervalsand sex: United States, 1966-70-Can.

Skeletalage

(h;~d&-%s#

Below 90----------------

90-95...................

96-101------------------

102-107-----------------

108-113-----------------

114-119-----------------

120-125-----------------

126-131-----------------

132-137-----------------

138-143-----------------

144-149-----------------

150-155-----------------

156-161-----------------

162-167-----------------

168-173-----------------

174-179-----------------

180-185-----------------

186-191-----------------

192-197-----------------

198-203-----------------

204-209-----------------

210-215-----------------

216-221-----------------

222-223-----------------

Percentile

P,B ---------------------

PmO---------------------

P*~ ------” --------------

Girls—chronological age in months

144-149 150-155 156-161 162-167 168-173 174-179 180-185 186-191 192-197 198-203

Percent distribution—male standard

-

.

0.4

0.4

2.1

0.8

1,5

5.9

10.0

15.0

20.5

19.2

9.2

7.9

4.0

1.9

0.9

0.3

179.1

171.7

163.7

0.4

0.6

1.6

2.3

1.9

7.0

7.0

14.6

21.9

14.5

10.1

11.8

3.7

1.2

1.1

0.3

189.0

178.3

170.6

0.6

4.9

4.3

15.0

17.4

15.0

14.7

14.2

10.2

2.9

0.5

0.3

.

193.4

182.3

174.1

-

0.4

1.0

2.6

5.0

15.3

12.9

11.8

22.0

14.4

10.5

3.4

0.7

0.4

0.3

0.8

3.2

S.8

7.3

7.7

25.1

27.9

15.1

5.5

0.9

0.4

0.7

4.1

2.6

6.3

21.4

23.4

25.0

11.0

3.6

1.5

0.4

2.7

3.4

17.3

20.3

25,7

16.6

10.4

3.2

Skeletalage (hand-wrist)in months

200.0

192.3

180.4

203.2 207.8

197.8 202.1

191.4 195.0

211.3

205.0

198.4

0.2

0.7

3.4

15.8

14.8

25.5

24.3

6.9

8.4

212.5

207.2

200.6

.

1.2

0.8

9.2

14.4

12.6

28.0

18.5

15.3

216.9

211.4

203.5

4.4

0.3

0.9

1.3

1.8

1.5

1.7

2.0

2.9

4.1

4.7

6.6

8.6

6.2

5.5

10.2

10.9

10.1

8.2

4.3

3.8

204.5

189.1

166.9

59
Table 4. Percent distributionand selectedpercentilesfor skeletalage (hand-wrist)in months of youths, by chronologicalage

at last birthday in 6-nmnth intervalsand sex: United States, 1966-70-con.

skeletalage

(h&dL-h;;;)

Belew 90----------------

90-95-------------------

96-101------------------

102-107-----------------

10s-113-----------------

114-119-----------------

120-125-----------------

126-131-----------------

132-137-----------------

13s-143-----------------

144-149-----------------

150-155-----------------

156-161-----------------

162-167-----------------

168-173-----------------

174-179-----------------

180-185-----------------

186-191-----------------

192-197-----------------

198-203-----------------

204-209-----------------

210-215-----------------

216-221-----------------

222-223-----------------

Percentile

P,B---------------------

P~o---------------------

P25---------------------

Girls-chronological age in months

144-149 150-155 156-161 162-167 16S-173 174-179 180-185 186-191 192-197 198-203

0.4

0.4

2.9

2.3

16.3

21.,8

18.6

17.5

7.1

6.6

3.0

1.9

0.9

0.3

.

147.1

139.7

132.7

0.4

0.2

1.1

3.7

9.2

9.5

17.4

20.5

10.4

11.2

10.1

2.6

2.3

1.1

.

0.3

158.0

146.3

138.6

.

0.2

5.8

8.4

15.1

19.6

9.8

15.2

12.1

9.1

2.7

1.7

.

0.3

.

-

Percent distribution-female equivalent

.

0.4

1.0

3.1

8.3

15.6

10.0

13.8

18.8

12.1

9.7

5.7

0.8

0.7

-

0.4

0.5

1.4

3.8

7.2

5.5

10.2

21.7

23.5

17.1

6.0

1.8

0.9

.

,-

0.4

1.6

3.4

3.4

8.1

18.6

19.1

21.0

14.7

4.6

3.6

1.5

-

-

0.4

3.7

2.8

17.0

17.6

21.6

13.4

9.9

10.4

3.2

Skeletalage (hand-wrist)in months

0.2

0.3

0.8

5.7

13.2

11.3

20.7

21.1

11.3

6.9

8.5

187.5

179.2

171.6

-

.

-

1.2

-

2.1

8.0

12.9

9.0

21.0

12.1

18.4

15.3

.

162.4 170.0 174.2 179.s 185.3

150.3 161.3 167.8 173.1 177.0

142.1 148.4 160.4 164.0 168.4

I I I I

192.9

185.4

174.5

4.5

0.1

0.5

1.4

2.6

2.5

3.8

6.3

6.1

6.8

8.7

4.6

6.1

8.8

9.5

8.6

7.0

4.0

4.3

3.8

.

175.5

158.1

135.0

40
Table 5. Percent of youths showing the number of radio-opaquehand-wrist bones—oaaifying and adult—by

chronologicalage in yeara at last birthdayand sex: United Statea, 1966-70

Number of

hand-wrist

bones oaaifying

Total with one or more

bones ossifying~

only

2 or

3 or

4 or

5 or

6 or

7 or

8 or

9 or

one---------------

less--------------

less--------------

leas--------------

less--------------

lesa--------------

less--------------

less--------------

less--------------

10 or less-------------

11 or less-------------

12 or less-------------

13 or less-------------

14 or less-------------

15 or less-------------

16 or less-------------

17 or less-------------

18 or lesa-------------

19 or less-------------

20 or leaa-------------

21 or less-------------

22 or less-------------

23 or less-------------

24 or less-------------

25 or less-------------

26 or leas-------------

27 or less-------------

28 or less-------------

29 or lesa-------------

30 or leas-------------

31 or leas-------------

Number of bonea

ossifyingper youth

Mean-------------------

,x-.-------------------

Boys—chronologicalage in years Girls—chronologicalage in years

I

12 13 14 15 16 17 12 13 14 15 16 17

Percent of youths

0.1

0.1

0.1

0.1

0.1

0.2

0.2

0.5

0.6

0.6

0.6

0.6

16.6

63.3

85.2

00.0

29.3

1.08

0.1

0.4

0.4

0.4

0.4

0.5

0.5

0.5

0.5

0.5

0.7

0.7

0.7

0.7

0.8

1.7

1.8

2.0

2.1

2.4

3.7

5.1

7.5

8.2

8.6

9.0

9.8

16.6

40.5

63.2

.00.0

29.1

3.28

3.C

3.8

4.0

4.2

5.2

5.5

5.8

6.0

6.5

7.6

7.8

8.5

8.5

9.8

12.1

13.4

14.5

15.0

16.2

22.4

24.2

27.8

30.0

30.6

31.8

32.4

34.8

42.5

57.8

Loo.o

26.1

7.55

0.6

12.9

15.4

17.3

18.9

22.1

23.3

24.4

25.2

27.2

28.2

29.2

30.0

31.8

34.2

38.3

40.1

41.7

42.5

45.8

53.3

55.2

58.5

59.6

60.9

61.8

62.7

65.2

70.4

75.5

100.0

19.3

LO.55

6.5

33.0

39.8

43.1

45.4

51.0

52.2

53.3

54.0

56.5

58.2

59.2

59.9

61.0

63.7

69.1

70.2

72.2

73.5

75.2

78.9

80.0

81.0

82.0

82.7

83.4

84.8

85.9

88.3

90.4

LOO.O

11.7

10.49

2.2.1

56.!

61./

64.(

66.L

72.2

74.t

76.(

77.t

78.4

79.5

81.5

83.5

84.?

85.5

88.1

89.5

90.4

90.s

92.0

93.2

93.2

93.9

94.1

94.8

95.8

96.4

97.1

97.7

98.3

LOO.0

6.3

7.49

0.1

3.1

3.7

3.8

4.7

5.2

5.7

6.2

6.3

6.5

7.0

7.5

7.9

8.7

10.3

14.9

16.1

17.3

18.5

20.2

22.8

24.4

29.4

31.2

32.8

34.9

36.7

38.7

45.1

62.4

LOO.0

25.7

7.48

0 .:

9.2

11.2

12.:

14.5

18.4

19.$

22.7

24.1

24.7

25.9

28.C

29.7

30.9

34.3

39,9

42.0

44.7

46.5

47.9

50.2

51.4

56.2

57.8

59.4

62.0

63.6

67.3

72.3

78.9

.00.0

19.5

.0.11

4.C

27.2

32.4

36.9

40.2

48.5

51.9

53.9

55.5

56.8

59.9

61.4

64.2

66.1

69.2

72.9

74.6

77.0

78.1

80.4

83.1

83.8

84.5

85.0

86.0

87.0

87.6

89.0

89.9

93.0

100.0

11.2

9.62

16.6

53.0

57.5

61.3

64.1

69.8

74.9

76.9

78.9

81.8

82.6

84.2

85.4

86.8

88.1

91.1

92.0

93.6

94.5

95.5

95.9

96.0

96.4

97.7

97.9

97.9

98.2

98.6

98.8

99.0

.00.0

5.9

6.46

42.1

70.1

75.1

78.0

80.2

85.0

86.7

88.4

89.4

90.4

92.3

92.6

93.7

94.5

95.0

96.5

96.9

97.6

97.8

98.6

98.8

99.0

99.0

99.0

99.4

99.6

99.6

99.8

100.0

100.0

100.0

3.6

4.25

46.8

70.1

76.3

78.9

82.5

86.9

88.6

90.1

90.8

91.9

92.4

93.5

94.4

95.4

96.2

97.3

97.9

97.9

99.0

99.4

99.4

99.4

99.7

99.7

99.7

100.0

100.0

100.0

100.0

100.0

100.0

3.4

4.25

lRadio-opaquebut not yet “adult.”

61
Table 5. Percent of youths showing the number of radio-opaquehand-wrist bones-ossifying and adult-by

chronologicalage in years at lsst birthdayand sex: United States,1966-70—Con.

Number of

hand-wrist

bones “adult”

Total with one or

more bones “adultJ’

Only

2 or

3 or

4 or

5 or

6 or

7 or

8 or

9 or

One ---------------

lesa--------------

less--------------

less--------------

less--------------

less--------------

lesa--------------

less--------------

less--------------

10 or less -------------

11 or less-------------

12 or less-------------

13 or less-------------

14 or less-------------

15 or less-------------

16 or less-------------

17 or leaa-------------

18 or leaa-------------

19 or less-------------

20 or less-------------

21 or less-------------

22 or less-------------

23 or les’s-------------

24 or less-------------

25 or less-------------

26 or less-------------

27 or less-------------

28 or less-------------

29 or less-------------

30 or less-------------

31 or less-------------

Number of “adult”

bones per youth

with adult bones

Mean-------------------

Sx ---------------------

BOYS—chronological age in years Girls—chronological age in years

12 13 14 15 16 17 12 13 14 15 16 17

Percent of youths

39.5

58.5

74.6

74.6

79.5

79.5

79.5

89.8

89.8

96.5

96.5

96.5

96.5

96.5

100.0

100.0

100.0

100,0

100.0

100.0

100.0

Loo.o

100.0

100.0

LOO.O

LOO.O

LOO.O

LOO.O

LOO.O

LOO,O

LOO,O

3.5

3.48

19.6

31.2

39.7

44.3

46.6

48.6

52.8

71.7

76.8

85.4

87.0

87.8

88.6

90.5

95.2

96.0

96.0

96.0

96.0

97.0

97.0

97.0

97.0

97.0

97.8

97.8

97,8

97.8

99.3

100,0

100.0

7.2

5.89

12.8

20.2

25.4

27.9

30.5

32.5

37.4

49.6

54.7

67.4

69.9

71.1

73.4

76.3

82.1

84.1

84.1

85.2

85.5

88.1

88.6

89.1

89.7

90.4

91.9

92.4

93.5

95.5

99.8

100.C

100.0

11.6

8.14

7.5

14.5

18.2

20.0

21.9

23.8

26.8

35.0

38.7

50.3

53.7

54.9

57.1

59.8

65.5

68.3

69.6

70.7

71.6

73.7

75.3

76.2

77.3

78.5

81.6

83.4

85.2

88.2

99.1

99.7

100.0

16.4

9,38

5.2

10.2

12.9

14.5

16.0

17.4

19.7

25.1

27.8

36.4

39.2

40.5

42.7

44.9

50.7

53.4

54.7

55.8

56.6

58.9

60.7

61.5

62.8

63.9

68.2

70.4

72.9

78.2

96.1

99.0

100.0

21.8

8.68

0.4

1,2

1.8

2.0

3.0

3.6

3.8

4.4

4.4

5.5

6.5

6.9

7.8

9.0

11.4

12.5

13.4

15.2

16.5

18.0

18.8

19.5

21.1

23.7

29.0

30.7

33.0

39.2

69.6

89.5

100.0

25.8

6.64

8.5

11.6

15.2

19.4

24.2

27.3

34.1

44.2

47.0

53.4

57.4’

60.1

62.5

66.8

77.0

80.3

81.5

82.4

83.6

84.9

85.3

85.5

86.7

87.8

89.5

91.4

91.4

93.1

99.6

100.0

100.0

11.7

7.91

5.1

10.4

14.6

17.5

21.3

23.9

27.9

35.6

37.6

41.8

44.4

47.1

50.4

53.9

62.4

66.4

67.9

69.5

72.0

73.1

73.8

75.3

78.1

79.6

83.9

85.7

86.6

89.8

99.4

99.8

100.0

15.4

9.11

3.7

7.0

10.1

12.0

14.7

16.5

19.1

23.8

25.2

28.9

31.5

33.5

36.5

39.3

45.9

49.6

51.6

53.5

55.8

57.7

58.9

60.4

62.9

65.5

71.6

74.3

77.0

81,5

97.8

99.6

100.0

21.7

7.98

2.6

4.9

7.1

8.5

10.4

11.7

13.8

17.2

18.2

20.8

22.9

24.6

27.1

29.3

34.8

37.7

39.5

41.2

43.2

44.8

46.5

48.2

50.5

54.0

59.8

62.4

65.6

70.7

92.4

98.6

100,0

25,5

5.94

2.0

3.8

5.6

6.7

8.2

9.2

10.9

13.4

14.2

16.3

18.1

19.4

21.5

23.3

27.7

30.1

31.6

33.2

34.8

36.4

37.9

39.4

41,5

44.6

50.1

52.5

55.6

60.6

83.1

96.4

100.0

27.7

4.56

0.2

0.2

0.2

0.4

0.4

0.4

0.8

1.6

1.8

2.1

2.9

3.8

4.6

5.3

5.9

6.3

7.2

7.7

8.9

10.4

13.8

16.4

18.5

23.6

42.5

78.2

100.0

28.4

4.01

62
Table 5. Percent of youths ahowing the number of radio-opaque hand-wrist bones —oas ifying and adult —by

chronological age in years at laat birthday and sex: United States, 1966-70—Con.

Number of hand-wrist

bones not yet

radio-opaque

Total with one or

more bones not yet

radi o-opaque

Ofily one---------------

2 or lesa --------------

3 or leaa --------------

4 or less --------------

Number of unformed

bones per youth

Mean -------------------

ax ----------------- ”---

Boys —chronological age in yeara Girls —chronological age in years

12 13 14 15 16 17 12 13 14 15 16 17

21.7

67.8

83.4

83.4

1.6

0.91

22.9

56.5

67,2

67,2

0.8

0.94

20.8

45.3

52.5

52.5

0.3

0.56

17.3

36.1

41.7

41.7

0,1

0.31

Percent of youths

15.2 3.7 19.7 14.8

30.6 3.9 24.0 17.3

35.1 - 24,4 17.5

35.1 4.1 24.6 17.6

0.1 0.1 0.3 0.1

0.27 1.01 0.58 0.34

12.0

13.8

13.9

13.9

0.1

0.24

10.4

11.8

11.9

11.9

0.1

0.24

8.8

9.9

10.0

10.0

0.0

0.13

1.9

2.3

2.3

2,3

0.0

0.15

63
Table 6. Mean, standard deviation, and standard error of mean(sx)bone-specificskeletal ages

for the 31 individual hand-wrist bones of youths and the number of youths, by chronological

age in years at last birthday and sex: United States, 1966-70

Radio-opaque

(not adult)

hand-wrist bone and value

Radius:

Mean------------------------------------

‘x--------------------------------------

---------------------------------------

Uh%a:

Mean------------------------------------

Sx--------------------------------------

s~--------------------------------------

Capitate:

Mean------------------------------------

Sx--------------------------------------

~i--------------------------------------

Hamate:

Mean------------------------------------

s% --------------------------------------

%--------------------------------------

Triquetral:

Flean-------------------------------------

Sx --------------------------------------

SF --------------------------------------

Lunate:

Mean------------------------------------

% --------------------------------------

--------------------------------------

Sc;~hoid:

Mean------------------------------------

Sx --------------------------------------

Sg--------------------------------------

Trapezium:

Mean------------------------------------

-$x --------------------------------------

s~ --------------------------------------

Tr;~a~id:

------------------------------------

5X --------------------------------------

s~--------------------------------------

Metacarpal 1:

Mean------------------------------------

Sx--------------------------------------

s~ --------------------------------------

Metacarpal 11:

Mean------------------------------------

% ‘------------------------------------- --------------------------------------

lIeZcarpal 111:

Mean------------------------------------

.5X--------------------------------------

SF--------------------------------------

Metacarpal IV:

Mean------------------------------------

5X --------------------------------------

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

Me;icarpal V:

Mean------------------------------------

% --------------------------------------

SE---------------------------------------

Pislform:

Mean------------------------------------

5X --------------------------------------

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

Ad~;;or sesamoid:

------------------------------------

% --------------------------------------

%--------------------------------------

Boys— chronological age in years

12 13 14 15 16 17

,Bone-specific skeletal age in months-male

139.8

16.52

0.69

140.0

16.28

0.67

140.9

1:.:;

.

142.0

16.94

0.66

140.6

16.73

0.70

140.4

17.25

0.65

139.0

17.27

0.63

138.2

18.20

0.62

138.8

1;.:5

.

138.6

17.52

0.61

138.5

17.54

0.67

139.2

1;.:;

.

139.1

17.93

0.68

139.5

18.13

0.69

141.1

17.10

0.64

159.7

7.22

0.50

157.2

17.66

0.86

156.8

17.72

0.86

155.8

16.76

0.97

156.5

16.65

0.97

155.1

1;.$:

.

155.3

17.16

0.89

154.5

17.84

0.93

154.5

18.75

1.01

154.9

18.53

1.00

155.4

18.00

0.79

155.6

18.25

0.89

156.1

18.39

0.85

156.1

18.57

0.87

156.5

18.48

0.85

155.9

17.65

0.64

165.0

9.49

0.49

standard

173.5

15.72

0.71

173.0

15.50

0.72

167.8

12.54

0.90

168.4

12.10

0.88

167.3

12.90

0.97

167.4

12.79

0.95

167.0

13.61

0.94

167.2

13.31

0.90

167.4

12.82

0.90

169.3

12.67

0.65

171.4

15.21

0.81

171.6

14.46

0.76

171.7

14.60

0.75

172.0

14.55

0.74

167.3

13.64

0.94

l;oi;

0;42

186.3

14.72

0.63

185.7

14.55

0.63

175.0

11.31

1.06

175.6

10.96

1.07

174.6

11.49

1.11

174.4

11.12

1.03

174.8

11.46

1.07

174.7

11.52

1.00

174.8

11.56

1.04

176.4

9.44

0.56

182.1

14.43

0.62

181.6

13.24

0.54

181.6

13.15

0.62

182.3

13.73

0.66

174.3

11.29

1.17

175.0

9.41

0.62

;;74:

0:73

194.4

13.42

0,81

176.9

11.93

1.54

178.1

11*13

1.44

176.9

11.97

1.40

176.4

12.08

1.61

176.6

12.15

1.61

176.7

11.37

1.44

176.4

11.65

1.49

178.9

9.27

0.83

187.6

14.62

1.23

187.2

13.56

1.12

187.1

13.45

0.93

189.0

14.29

0.92

176.8

12.61

1.75

177.1

10.57

1.08

207.1

11.96

0.49

201.9

8.46

0.55

184.9

8.46

1.79

185.2

8.07

1.70

185.6

7.76

1.65

1;56:

1:69

185.8

8.14

1.69

185.2

~.;:

.

185.2

;.;;

.

183,2

4.11

0.50

196.0

10.60

0.92

1;45;

0:83

193.4

9.19

0.78

196.0

1:.ztt

.

185.7

7.50

2.25

183.6

:.;:

.

64
“- .-

Table 6. Mean, standard deviation, and standard error of mean(s~)bone-specific skeletal ages

for the 31 individual hand-wrist bones of youths and the number of youths, by chronological

age in years at last birthday and sex: United States, 1966-70—Con.

Girls—chronological age in years

12 13 14 15 16 17

Bone-specific skeletal age in months—male

173.9

15.03

0.73

173.5

15.42

0.76

168.2

13.20

0.71

169.1

If. ::

.

167.5

12.93

0.70

167.4

13.16

0.62

166.7

13.88

0.60

166.7

1;. :3

.

166.9

13.86

0.60

170.3

1;.;;

.

171.7

15.19

0.74

172.3

14.69

0.70

171.9

1$;;

.

172.4

14.88

0.70

167.1

13.42

0.64

169.8

9.48

0.39

185.8

13.36

0.65

185.4

13.54

0.69

175.8

10.38

0.74

176.5

1:.:;

.

174.9

10.80

0.72

174.8

10.66

0.71

174.7

1:.;;

.

175.0

1;. :;

.

175.0

10.31

0.70

177.4

8.88

0.51

;:36;

0:60

182.9

12.87

0.63

182.7

12.72

0.66

183.4

13.31

0.62

1;4;:

0:63

174.4

9.27

0.59

standar~

198.0

12.45

0.53

196.6

11.37

0.63

181.5

10.17

0.90

181.5

10.42

1.02

181.3

10.61

0.98

180.8

10.57

0.98

180.7

10.83

0.99

180.7

10.78

0.95

181.0

1;.;:

.

181.0

7.38

0.51

194.2

12.76

0.78

192.7

11.41

0.58

192.5

11.30

0.58

194.3

12.52

0.63

182:0

9.60

0.90

1;9;:

0:72

208.6

10.18

0.50

203.7

7.52

0.40

1;8;;

1:80

188.7

4.96

1.71

l;8~;

2:05

187.9

5.60

2.19

187.6

6.30

2.22

188.6

5.27

1.66

188.4

5.55

1.84

185.2

2.13

0.28

198.8

9.01

0.86

196.7

6.88

0.62

197.2

7.05

0.57

199.3

8.94

0.64

186.0

6.42

1.35

179.9

7.95

1.03

214. Z

10.6[

0.4:

206.f

6.lL

0.5:

186.i

8.9:

2.21

184.5

13.5(

3.7:

184.E

13.31

3.87

188.7

5.46

1.32

188. c

5.4E

1.45

189.1

4.64

0.92

189.0

4.39

1.07

185.5

2.12

0.48

203.3

7.42

0.85

200.2

5.24

0.65

200.3

5.45

0.75

203.1

7.12

0.91

188.2

5.93

1.33

181.1

8.67

1.54

217.1

5.83

0.34

208.4

4.08

0.35

191.7

0.71

0.40

191.6

0.76

0.53

191.7

0.76

0.50

191.2

1.58

*60.47

190.8

2.90

1.36

192.0

192.0

185.9

0.61

0.13

2;4i;

1:29

2$);:

1:21

200.6

4.77

1.11

205.1

6.53

0.96

192.0

184.1

6.75

1.92

Girls—chronological age in years

12 13 14 15 16 17

Bone-svecific skeletal age in months-female

equival&t

141.9

12.23

0.60

141.5

12.58

0.62

136.2

10.69

0.57

137.1

10.28

0.53

136.2

10.51

0.57

136.2

10.71

0.50

134.7

11.22

0.48

134.9

11.18

0.51

135.0

1;.$

.

138.3

10.35

0.53

139.7

12.36

0.60

140.3

11.96

0.57

139.9

12.00

0.55

140.4

12.12

0.57

135.6

10.89

0.52

137.8

7.69

0.48

153.8

11.06

0.54

153.4

11. 2C

0.57

143.8

8.49

0.61

144.5

8.20

0.65

141.9

8.76

0.58

141.8

8.65

0.58

142.7

8.90

0.63

l;zi;

0:51

142.0

8.37

0.57

145.4

7.28

0.42

::l;~

0:50

150.9

10.62

0.52

150.7

10.49

0.54

151.4

10.99

0.51

141.8

7.92

0.51

142.4

7.57

0.48

168.6

10.6C

0.45

167.2

9.67

0.54

149.0

8.35

0.74

149.5

8.58

0.84

149.3

8.74

0.81

148.8

8.70

0.81

148.7

8.91

0.81

148.7

8.87

0.78

149.0

8.71

0.73

149.0

6.08

0.42

164.2

10.79

0.66

161.7

9.57

0.49

162.0

:.5J

.

162.6

10.48

0.53

150.0

7.91

0.74

147.0

7.88

0.59

182.2

8.89

0.44

174.4

6.44

0.34

157.0

4.72

1.50

157.7

4.15

1.43

156.4

4.48

1.70

156.8

4.67

1.83

156.2

5.24

1.85

156.6

4.38

1.38

156.4

4.61

1.53

1:4;;

0:23

168.8

7.65

0.73

166.7

5.83

0.53

167.2

5.98

0.48

169.3

7.59

0.54

154.0

5.32

1.12

147.9

6.54

0.85

l;oi$

0;37

179.4

5.34

0.48

155.4

7.45

1.84

152.9

11.16

3.08

152.8

11.01

3.20

157.7

4.56

1.10

157.0

4.58

1.21

157.1

3.85

0.76

157.0

3.65

0.89

154.5

1.77

0.40

174.3

6.36

0.73

l:oi:

0:55

170.3

4.63

0.64

173.2

6.07

0.78

156.2

4.92

1.10

149.1

7.14

1.27

194.1

5.21

0.30

181.4

3.55

0.30

1:1;:

0:34

161.6

0.64

0.45

161.7

0.64

0.42

160.2

1.32

h50.67

159.8

2.43

1.14

161.0

161.0

154.9

0.51

0.11

l;5i:

1:11

l~o;g

1:03

170.6

4.06

0.94

176.1

5.61

0.82

160.0

152.1

5.58

1.59

65
-.,“

Table 6. Mean, standard deviation, and standard error of mean(sz)bone-specificskeletal agea

for the 31 individual hand-wrist bones of youths and the number of youths, by chronological

age in years at last birthday and sex: United States, 1966-70—Con.

Radio-opaque (not adult)

hand-wrist bone and value

Fleex:nrsesamoid:

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

Sx--------------------------------------------

--------------------------------------------

Pr~ximal phalanx I:

Mean------------------------------------------

Sk--------------------------------------------

s~--------------------------------------------

Proximal phalanx II:

Mean------------------------------------------

Sx--------------------------------------------

s~--------------------------------------------

Proximal phalanx III:

Mean------------------------------------------

s~--------------------------------------------

%:-------------------------------------------

Proxunal phalanx IV:

Mean------------------------------------------

Sx--------------------------------------------

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

Pr&mal phalanx V:

Mean------------------------------------------

--------------------------------------------

2--------------------------------------------

Middle phalanx II:

Mean------------------------------------------

s% ---------------------------- ------------------

.%---- -------- -------- -------- -------- ------

Meddle phalanx III:

Mean------------------------------------------

sx--------------------------------------------

- ------------------------------------------

Mi?dl; phalanx IV:

Mean------------------------------------------

%

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

--------------------------------------------

Mi?dle phalanx V:

Mean------------------------------------------

Sx --------------------------------------------

-------- -------- -------- -------- -------

Di%t;i-jialanx I:

Mean------------------------------------------

s% -------- ------------------------- -------- ----

SF --------------------------------------------

Distal phalanx II:

Mean------------------------------------------

% --------------------------------------------

SF--------------------------------------------

Distal phalanx 111:

Mean------------------------------------------

s% --------------------------------------------

-------- -------- -------- -------- -------- ----

Di~tal phalanx IV:

Mean------------------------------------------

Sx--------------------------------------------

.=------ --------------------------------------

Dustal phalanx V:

Mean------------------------------------------

sx--------------------------------------------

SF-------------------------------.------------

Boys—chronological age in years

Bone-specific skeletalage in months-male

standard

165.2

6.07

0.56

140.6

18.00

0.73

140.6

1;.;:

.

140.8

17.91

0.68

140.6

17.72

0.72

140.9

17.54

0.72

141.6

1;.23

.

141.6

1:.;;

.

140.9

17.46

0.69

141.2

1;.:;

.

139.9

1;.:$

.

140.0

17.49

0.63

139.9

17.43

0.63

140.2

17.40

0.64

140.2

17.55

0.64

168.5

8.13

0.68

157.5

18.66

0.81

158.0

18.71

0.87

158.3

18.73

0.89

158.1

19.10

0.93

158.1

18.92

0.93

158.0

1:.;2

.

158.1

18.28

0.91

157.6

18.68

0.92

157.7

1;.;:

.

155.8

17.41

0.88

156.3

17.33

0.86

156.0

17.47

0.89

156.2

17.27

0.86

156.2

17.19

0.86

172.0

8.09

0.40

172.7

15.19

0.85

172,3

14.67

0.92

172.4

14.61

0.95

172.6

15.05

0.96

172.3

14.90

0.92

172.3

14.65

0.81

172.4

14.61

0.84

172.3

15● 01

0.86

172.2

14.75

0.84

168.4

12.26

0.69

168.7

12.16

0.68

168.6

Ij.!3:

.

168.8

1:.():

.

168.6

11.94

0.65

175.5

8.70

0.70

182.8

1;.;;

.

182.3

i3.17

0.68

182.6

1;.;:

.

182.5

1;.;:

.

182.5

1;.;;

.

181*8

12.48

0.77

182.3

12.52

0.72

182.0

12.32

0.70

;;2S&

0:63

175.7

11.;;

.

175.7

9.86

0.60

1;5;$

0:62

175.0

8.88

0.55

174.8

8.88

0.53

177.2

;.:3

.

188,1

1:.;;

.

187.1

13.58

1.47

186.7

1;.;;

.

187.1

13.39

1.21

186.8

1;.:;

.

187.2

12.66

1.03

187.2

12.43

1.08

187.0

12.25

0.96

187.0

12.53

0.99

179.5

11.10

1.10

179.2

10.62

1.00

178.7

10.57

1.00

177.9

9.15

0.89

178.2

9.05

0.91

185.4

8.33

2.30

198.3

1:.;;

.

195.5

9.02

1.00

195.7

8.85

1.02

195.1

9.06

1.05

l;w;

1006

194.9

8,98

0.90

195.5

8,84

0.74

l;5i;

0:80

194.6

9.09

0.86

186.3

8,08

0.93

186.0

7.46

0.77

185.9

7.88

0.83

183.4

4.34

0.56

183.1

4.59

0.61

66
Table 6. Mean, standard deviation, and standard error of mean(sz)bone-specificskeletal ages

for the 31 individual hand-wrist bones of youths and the number of youbhs, by chronological

age in years at last birthday and sex: United States, 1966-70—Con.

Girls—chronological age in years

12 13 14 15 16 17

Bone-specific skeletal a~e in months—male

standar~

172.0

8.43

0.53

174.9

1:.::

.

175.1

14.49

O*66

175.3

1;.::

.

175● 7

14.92

0.64

175.9

14.80

0.64

175.3

1;.;;

.

175.5

1;.;;

.

175.2

14● 41

0.64

175.2

14.59

0.66

170.8

12.89

0.63

170.9

12.85

0.65

170.7

1:.:;

.

170.5

12.38

0.59

170,5

12.60

0.61

175.8

8.31

0.63

184.9

13.76

0.80

183.8

12.53

0.64

184.0

12.42

0.68

;;4i;

0:74

184.3

12.60

0.71

184.3

12.40

0.86

184.5

11.94

0.75

184.6

11,89

0.74

184.1

12.11

0.81

178.4

10.92

0.84

178.7

1:,:3

●

178.4

1;.;:

.

176.4

8.40

0.82

176,6

8.60

0.85

180.1

8.42

0.82

195.5

1;.;:

.

193.0

12.07

0.64

193.6

11.89

0.59

193.4

11.74

0.66

193.4

11.95

0.56

192.6

11.41

0.65

193.3

11.36

0.61

193.1

11.15

0.61

192.6

11.57

0.60

183.4

1$;:

.

183.7

10● 17

0.76

183.5

1:.;;

.

180.8

7.75

0.53

180.9

7.73

0.56

180.8

6.29

1.16

2;3;;

0:94

199.1

7.15

0.51

199.5

7.03

0.52

199.3

7.12

0.56

2:04:

0:55

199.5

6.&8

0.58

199.0

6.56

0.62

198.9

6.62

0.57

198.7

7.22

0.74

191.0

8.48

1.40

191.3

8.84

1.44

191.3

8.92

1.50

185.8

0.72

0.09

185.7

0.90

0.12

183.6

7.10

1.05

206.5

5.92

0.98

201.9

4.78

0.85

202.4

$.::

.

202.5

4.32

0.79

2:2;:

0:53

202.3

4.28

0.72

201.8

4.57

0.71

2:2i;

0:65

202.2

4.48

0.69

1:9<;

1:20

189.5

7.20

1.48

189..7

7.34

1.56

186.0

186*O

187.5

6.88

1.74

207.8

5.51

1.09

203.1

4.12

0.84

203.4

3.86

0.68

203.1

3.85

0.65

203.5

3.50

0.56

203.0

3.44

0.65

203.1

3.40

0.63

2;35;

0:60

203.0

3.52

0.64

l;7i;

0:91

187.4

5.20

0.97

187.4

4.96

0.96

185.9

0.36

0.07

185.9

0.50

0.09

Girls—chronological age in years

12 13 14 15 16 17

Bone-specific skeletal age in months-female

equivalent

140.c

6.8f

0.4:

141.9

11.72

0.54

142.1

11.76

0.54

144.3

11.85

0.54

144.4

12.26

0.53

143.9

12.11

0.52

143.3

11.62

0.53

143.0

11.42

0.48

142.2

11.70

0.52

143.2

11,93

0.54

138.8

10.48

0.51

138.9

1:,$;

.

138.7

10.30

0.50

138.5

10.06

0.48

138.5

1:.;;

.

143.8

6.80

0.52

152.9

11.38

0.66

150.9

10.29

0.53

152.0

10.26

0.56

152.3

10.46

0.61

152.3

1:.4J

.

152.3

10.25

0.71

152.5

9.87

0.62

152.6

9.83

0.61

152.1

10.01

0.67

1;6{;

0:69

145.4

:.:;

.

146.4

8.85

0.64

144.4

6.88

0.67

143.6

6.99

0.69

148.1

6.92

0.67

165.5

11.41

0.73

163.0

10.19

0.54

163.6

10.05

0.50

163.4

9.92

0.56

162.4

10.03

0.47

162.2

9.61

0.55

162.3

9.54

0.51

1;25;

0:51

162.2

9.74

0.51

151.2

8.77

0.74

151.7

8.40

0.63

151.5

8.40

0.64

148.8

6.38

0.44

148.9

6.36

0.46

148.8

5.18

0.95

174.4

7.63

0.81

169.1

6.07

0.43

170.0

5.99

0.44

169.6

6.06

0.48

170.0

5.89

0.47

170.2

5.53

0.49

1;0;:

0:53

169.8

5.65

0.49

168.7

6.13

0.63

161.0

7.15

1,18

161.3

7.45

1.21

161.3

7.52

1.26

152.4

0.59

0.07

153.7

0.74

0.10

151.6

5.86

0.87

178.5

5.12

0.85

171.9

4.07

0.72

173.4

3.80

0.69

173.5

3.70

0.68

1;3;:

0:45

172.6

3.65

0.61

172.8

3.91

0.61

1;36;

0:56

172.2

3.82

0.59

158.6

5.82

1.01

157.5

5.98

1.23

158.7

6.14

1.31

153.0

154.0

156.0

5.72

1.45

179.8

4.77

0.94

173,1

3.51

0.72

174.8

3.32

0.58

174.2

3.30

0.56

173.8

2.99

0.48

1;44;

0:56

174.1

2.91

0.54

174.1

2.88

0.51

173.0

3.00

0.55

155.2

$:$

.

lp:

0:80

ysi;

0:80

153.0

0.30

0.06

153*9

0.41

0.07

67
Table 6. Mean, standard deviation, and standard error of mean(sz)bone-specific

for the 31 individual hand-wrist bones of youths and the number of youths, by

age in years at last birthday and sex: United States, 1966-70—Con.

skeletal ages

chronological

Hand-wrist bone

Radius------------------------------------------------

Wna--------------------------------------------------

Cavitate----------------------------------------------

HWte ------------------------------------------------

=iquetral --------------------------------------------

Lunate------------------------------------------------

Scaphoid----------------------------------------------

Trapeziw ---------------------------------------------

Trapezoid---------------------------------------------

Metacarpal I------------------------------------------

Metacarpal II-----------------------------------------

Metacarpal III----------------------------------------

Metacarpal IV-----------------------------------------

Metacarpal V------------------------------------------

Pisifom ----------------------------------------------

Adductor sesamoid-------------------------------------

Flexor seaamoid---------------------------------------

Proximal phalanx I------------------------------------

Proximal phalanx II-----------------------------------

Proximal phalanx III----------------------------------

Proximal phalanx IV-----------------------------------

Proximal phalanx V------------------------------------

Middle phalanx II-------------------------------------

Middle phalanx III------------------------------------

Middle phalanx IV-------------------------------------

Middle phalanx V--------------------------------------

Distal phalanx I--------------------------------------

Distal phalanx 11-------------------------------------

Distal phalanx III------------------------------------

Distal phalanx IV-------------------------------------

Distal phalanx V--------------------------------------

Boys—chronological age in years

12 13 14 15 16 17

Number of youths in thousands

2,015

2,015

2,015

2,013

2,010

2,007

2,015

2,011

2,009

2,024

2,024~

2,024

2,024

2,024

1,657

795

336

2,017

2,024

2,024

2,024

2,024

2,024

2,024

2,024

2,024

2,023

2,023

2,023

2,023

2,019

2,000

1,998

1,815

1,807

1,822

I

1,825

1,844

1,842

1,843

1,981

1,993

1,993

1>993

1,990

1,638

1,338

857

1,996

1,993

1,993

1,993

1,990

1,993

1,993

1,993

1,993

1,952

1,963

1,958

1,951

1,954

1,948

1,948

1,373

1,345

1,373

1,356

1,376

1,367

1,354

1,755

1,869

1,858

1,867

1,867

1,305

1,346

1,080

1,823

1,800

1,797

1,801

1,788

1,805

1,813

1,819

1,804

1,594

1,651

1,645

1,643

1,639

1,883

1,864

769

752

768

764

778

760

755

1,239

1,513

1,491

1,497

1,547

689

805

739

1,386

1,361

1,369

1,363

1,355

1,376

1,412

1,400

1,392

1,031

1,076

1,083

1,036

1,047

1,770

1,642 ~

351

328 i

336

337

328

337

317

631

939

939

933

1,031

305

396

348

791

762

752

761

738

793

830

827

821

503

517

528

483

513

1,544

1,138

103

103

106

106

106

103

103

194

498

433

415

518

83

115

84

397

329

341

303

319

351

376

373

351

210

213

203

188

181

68
Table 6. Mean, standard deviation, and standard error of mean(sX)bone-specific

for the 31 individual hand-wristbones of youths and the number of youths,by

age in years at last birthdayand sex: IJnitedstates,1966-70—con.

skeletalages

chronological

Girls-chronologicalage in years

12 13 14 15 16 17

Number of youths in thousands

1,953

1,950

1,347

1,326

1,338

1,347

1,360

1,369

1,350

1,735

1,847

1,851

1,851

1,865

1,266

1,413

1,097

1,816

1,800

1,807

1,799

1,791

1,809

1,822

1,822

1,803

1,520

1,549

1,537

1,504

1,502

1,943

1,935

874

860

861

845

876

884

874

1,287

1,643

1,628

1,611

1,682

825

976

851

1,458

1,399

1,412

1,417

1,390

1,416

1,463

1,466

1,370

957

983

978

888

879

1,878

1,793

305

296

305

319

332

323

319

513

1,120

1,079

1,103

1,217

345

459

389

832

730

777

776

734

740

808

814

720

418

440

438

368

375

1,755

1,403

67

64

60

70

72

80

68

227

503

488

517

610

89

191

135

379

362

385

367

351

317

352

362

294

228

220

219

167

153

1,549

776

37

37

37

33

34

35

35

65

242

223

230

299

41

78

67

166

135

147

153

168

138

149

150

146

133

110

105

93

97

1,278

481

29

25

25

22

36

36

36

80

158

122

143

208

39

73

74

142

112

122

143

136

98

108

107

96

120

120

116

107

119

69
Table 7. Mean and standard deviation (s,) of bone-specific skeletal ages for selected

hand-wrist bones of youths,by chronologicalage in 6-month intervals and sex: United

States, 1966-70

Chronological

age and sex

Boys (male standard)

12 years:

O-5 months-----------------

6-11 months----------------

13 years:

O-5 months-----------------

6-11 months ----------------

14 years:

O-5 months-----------------

6-11 months----------------

15 years:

O-5 months-----------------

6-11 months----------------

16 years:

O-5 months-----------------

6-11 months----------------

17 years:

O-5 months-----------------

6-11 months----------------

Girls (female eauivalent~

12 years:

O-5 months-----------------

6-11 months----------------

13 years:

O-5 months-----------------

6-11 months----------------

14 years:

O-5 months-----------------

6-11 months----------------

15 years:

O-5 months-----------------

6-11 months----------------

16 years:

O-5 months-----------------

6-11 months----------------

17 years:

O-5 months-----------------

6-11 months----------------

Radius Ulna Scaphoid Metacarpal I

Mean

134.6

144.1

153.2

161.9

171.6

175.3

183.5

189.4

193.8

201;6

205.5

208.9

138.5

144.5

150.3

158.8

165.6

170.5

180.4

183.7

189.2

192.3

193.6

194.7

s~ Mean Sx Mean s. Mean Sx

Bone-specific skeletal age in months

16.04

15.66

17.79

16.31

15.26

15.95

15.15

13.60

14.82

14.04

12.06

11.63

11.92

11.97

10.97

10.26

10.89

9.74

9.34

8.32

10.18

8.57

5.05

5.35

134.8

144.2

152.6

161.5

171.1

175.0

183.0

188.7

192.2

197.4

200● 3

203.9

137.9

144.6

151.0

158.6

164.8

169.6

173.2

175.8

179.0

179.9

181.4

181.3

15.81

15.42

17.81

16.36

15,20

15.55

15.08

13.35

13.99

11.96

9.26

6.81

12.19

12.35

L1.34

LO.38

10.14

8.74

7.04

5.64

5.13

5.59

;.:;

.

133.6

143.4

150.7

159.1

165.4

168.8

173.4

177.4

175.8

178.2

185.4

187.3

133.5

136.7

141.1

145.0

147.3

151.4

154.9

158.2

158.4

152.7

157.9

161.0

16.lC

16.92

17.82

16.75

13.73

13.26

11.28

11.32

13.60

8.36

8.42

4.63

10.98

11.31

8.28

9.45

9.32

7.51

5.24

4.95

3.20

5.97

2.83

132.7

143.4

151.2

160.2

168.0

170.8

174.9

178.4

178.6

179.5

183.2

183.3

136.6

140.2

144.1

147.4

147.9

151.7

153.9

154.5

155.0

153.9

155.0

154.8

16.68

16.72

18.29

16.38

12.66

12.52

9.89

8.40

10.41

6.54

4.31

3.60

10.56

9.88

7.53

6.55

6.80

4.37

1.92

1.48

2.6;

0.6;

71
Table 7. Mean and standard deviation (sX) of bone-specific skeletal ages for selected

hand-wrist bones of youths,by chronological age in 6-month intervals and sex: United

States, 1966-70—Con_.

Chronological

age and sex

Boys (male standard)

12 years:

O-5 months -------------------------

6-11 months ------------------------

13 years:

O-5 months -------------------------

6-11 months ------------------------

14 years:

O-5 months -------------------------

6-11 months ------------------------

15 years:

O-5 months -------------------------

6-11 months ------------------------

16 years:

O-5 months -------------------------

6-11 months ------------------------

17 years:

O-5 months -------------------------

6-11 months ------------------------

Girls (female equivalent)

12 years:

O-5 months -------------------------

6-11 months ------------------------

13 years:

O-5 months -------------------------

6-11 months ------------------------

14 years:

O-5 months -------------------------

6-11 months ------------------------

15 years:

O-5 months -------------------------

6-11 months ------------------------

16 years:

O-5 months -------------------------

6-11 months ------------------------

17 years:

O-5 months -------------------------

6-11 months ------------------------

I 1

Pisiform Adductor Flexor

Mean 5X Mean Sx Mean s~

Bone-specific skeletal age in months

135.5

145.3

152.5

159.8

166.5s

168.2

172.4

177.5

175.4

179.6

185.1

188.0

135.1

136.2

140.7

144.8

148.7

152.3

152.2

158.1

156.7

155.2

160.0

160.0

15.74

16.86

17.28

17.25

13.18

14.13

11.28

10.56

13.86

9.08

7.81

5.67

10.22

11.58

7.81

7.73

8.35

6.66

5.62

1.97

4.20

6.08

158.1

160.4

163.1

166.8

169.2

171.6

174.0

176.7

177.1

177.2

183.6

183.5

136.1

139.6

141.1

144.2

146.2

148.3

149.2

145.7

148.1

151.4

152.7

153.4

6.39

7.46

8..97

9.63

9.49

9.63

9.58

8.91

11.10

9.53

8.23

8.12

7.35

7.79

7.38

7“.59

8.29

7.04

;.;:

.

7.51

5.79

4.77

5.89

163.0

166.0

166.9

170.1

171.4

172.7

174.3

177.4

176.4

178.9

184.3

189.4

138.4

141.7

142.7

145.4

147.2

149.7

149.0

148.5

152.6

149.9

153.8

157.7

5.64

6.02

7.54

8.35

7.77

8.38

8.34

8.93

10.50

8.37

8.78

4.56

6.40

7.05

6.50

7.00

6.97

6.65

4.79

5.75

5,23

6.63

6.69

4.56

72
Table 7. Mean and standard deviation (s,) of bone-specific skeletal ages for selected

hand-wrist bones of youths,by chronologicalage in 6-month intervals and sex: United

States, 1966-70—Con.

Chronological

age and sex

Boys (male standard)

12 years:

O-5 months---------------------

6-11 months--------------------

13 years:

O-5 months---------------------

6-11 months--------------------

14 years:

O-5 months---------------------

6-11 months--------------------

15 years:

O-5 months---------------------

6-11 months--------------------

16 years:

O-5 months---------------------

6-11 months--------------------

17 years:

O-5 months---------------------

6-11 months--------------------

Girls (female equivalent)

12 years:

O-5 months---------------------

6-11 months--------------------

13 years:

O-5 months---------------------

6-11 months--------------------

14 years:

O-5 months---------------------

6-11 months--------------------

15 years:

O-5 months---------------------

6-11 months--------------------

16 years:

O-5 months---------------------

6-11 months---------------------

17 years:

O-5 months---------------------

6-11 months--------------------

Proximal Middle

phalanx 11 phalanx 11 Distal phalanx II

Mean Sx Mean SX Mean s%

134.5

145.5

153.6

163.0

170.5

174.1

180.5

184.8

186.8

187.6

194.0

198.0

139.2

144.8

149.0

155.8

159.8

164.3

168.5

170.1

172.2

171.5

173.3

172.9

Bone-specific skeletal age in months

16.80

17.39

18.76

17.35

14.40

14.73

13.97

11.55

14.40

11.96

9.19

8.00

11.15

11.90

10.02

9.89

10.76

8.72

6.34

5.56

3.27

5.07

1.82

4.47

135● 9

146.3

153.7

163.0

170.4

174.3

180.1

184.1

186.7

188.0

193.8

197.0

139.7

145.9

149.9

154.8

160.2

164.8

170.0

170.6

173.2

172.0

174.3

173.2

16.46

16.57

17.96

17.27

14.37

14.66

13.14

11.16

13.38

11.30

9.02

8.37

10.65

12.05

10.30

9.42

10.21

8.22

5.81

5.01

3.13

4.34

2.08

3.87

134.1

144.7

152.2

161.0

167.7

169.8

174.1

177.9

178.5

180.3

185.8

186.3

136.9

141.1

144.8

149.7

150.3

154.2

161.6

161.0

160.4

155.3

154.0

157.1

16.38

16.94

17.49

15.88

12.25

11.95

10.36

8.62

11.90

7.82

7.87

6.89

9.85

10.77

8.64

8.78

8.57

7.67

7.73

6.99

6.74

3.90

6.1;

73
Table 8. Selectedpercentilesin the distributionof bone-specificskeletalages for each of the

31 hand-wristbones of youths, by chronological age in years at laat birthday and sex: United

States, 1.966-70

Hand-wrist bone and percentile

Radius :

P75 -------------------------------------------

P50-------------------------------------------

P~i-------------------------------------------

Ulna:

P75-------------------------------------------

P50-------------------------------------------

P25-------------------------------------------

Capitate:

P75-------------------------------------------

P51J-------------------------------------------

p25-------------------------------------------

Hamate:

P75 -------------------------------------------

Pry)-------------------------------------------

Pz5-------------------------------------------

Triquetral:

P75-------------------------------------------

P5t3-------------------------------------------

Pz5-------------------------------------------

Lunate:

P7CJ-------------------------------------------

P5r3-------------------------------------------

P25-------------------------------------------

Scaphoid:

P75-------------------------------------------

P!jo -------------------------------------------

P~5-------------------------------------------

Trapezium:

P75 -------------------------------------------

Pfjo -------------------------------------------

PZ5 -------------------------------------------

Trapezoid:

P75 -------------------------------------------

P~()-------------------------------------------

Pz5-------------------------------------------

Metacarpal 1:

p75 -------------------------------------------

P= -------------------------------------------

-------- .--------- ---------- -----------_---

Me;&arpal II:

P75-------------------------------------------

P5(j-------------------------------------------

P~5-------------------------------------------

Metacarpal III:

P7~ -------------------------------------------

P~ -------------------------------------------,

P*5-------------------------------------------

Metacarpal IV:

P75 -------------------------------------------

P50 -------------------------------------------

P*5-------------------------------------------

MetacarpalV:

P75-------------------------------------------

P50-------------------------------------------

Pz5-------------------------------------------

Pisiform:

P75 -------------------------------------------

PyJ-------------------------------------------

Pz5-------------------------------------------

I.loya-chronological age in years

12 13 14 15 16 17

Bone-specific skeletal age in months-male

standard

152.6

140.5

127.0

152.5

140.8

126.9

156.0

140.8

128.3

156.3

142.9

129.3

;;!.;

128:2

154.5

142.2

127.3

152.7

139.2

126.0

153.0

139.0

122.7

153.3

140.1

123.0

153.8

138.7

125.4

153.2

138.7

124.1

154.8

139.0

123.6

154.5

138.8

124.2

155.3

140.3

125.3

156.3

140.6

127.0

171.0

159.7

146.9

170.6

157.0

146.2

168.3

159.5

144.9

168.5

160.0

147.2

168.5

156.7

144.5

168.4

157.2

144.5

168.5

156.5

142.4

168.6

156.9

142.9

168.6

158.0

143.4

170.1

157.3

143.6

168.9

158.0

144.4

170.3

159.2

144.6

170.6

159.2

144.2

170.4

160.4

144.8

168.9

158.5

144.5

184.3

175.0

163.0

183.6

174.6

162.9

176.7

168.9

160.9

177.0

170.3

162.2

176.8

168.6

160.5

176.6

168.9

160.3

176.8

168.9

160.1

176.9

168.8

160.4

176.6

168.8

160.7

178.3

172.5

162.6

180.3

172.9

163.7

180.3

173.8

164.2

180.4

174.0

164.4

180.8

174.2

164.6

178.0

168.8

160.7

198.4

186.7

177.0

198.1

185.2

176.7

184.1

176.8

168.6

184.7

176.9

170.1

183.2

176.4

168.4

180.9

176.2

168.5

183.1

176.3

168.7

180.9

176.3

168.8

181.0

176.3

168.9

184.9

178.1

172.5

192.8

180.5

174.3

192.6

180.4

174.6

192.6

180.5

174.7

193.0

180.7

174.7

182.4

176.2

168.3

208.7

200.1

189.2

204.9

198.6

186.5

186.9

176.8

170.5

187.6

178.9

172.6

186.8

176.9

168.8

187.2

176.8

170.0

187.5

176.8

172.1

186.5

176.9

169.5

186.4

176,6

170.3

186.4

183.2

175.5

196.8

190.2

177.2

197.0

190.4

177.3

196.8

190.1

177.0

198.4

191.0

180.4

188.4

176.7

170.5

216.3

210.0

199.4

209.9

204,9

198.0

192.4

186.9

180.3

192.4

:::.;

.

192.5

190.1

180.7

192.4

190.3

180.0

192.0

192.5

192.0

192.4

190.3

180.5

192.4

190.0

180.6

186.5

186.1

180.9

204.8

196.8

190.5

204.1

196.4

190.0

200.7

196.0

188.0

204.5

196.8

190.6

192.5

192.0

180.7

74
Table 8. Selected percentiles in the distribution of bone-specific skeletal ages for each of the

31 hand-wrist bonea of youths, by chronological age in years at last birthday and sex: IJnited

States, 1966-70—Con.

Girls-chronological age in years

..

12 13 14 15 16 17

Bone-specific skeletal age in months—male

184.!

175.e

165,:

184.?

175.5

164.$

176.f

168.$

L62.3

178.[

169.6

162.3

176.5

168.6

159.9

L76.6

168.7

L60.3

L76.4

L68.4

L60.4

L76.4

L68.5

L59.7

L76.4

I-68.6

L59.5

L80.3

L72.5

L64.6

L80.6

L72.8

L64.5

L80.8

!74.2

L65.2

L80.6

L74.O

164.6

L80.8

L74.O

164.9

L76.3

L68.7

1.60.6

194.7

186.2

178.1

196.1

185.6

177.3

183.7

177.3

168.7

184.2

178.1

169.0

182.4

176.4

168.5

181.1

176.2

168.6

182.0

;;;.;

.

181.0

176.1

168,6

181.0

176.1

168.8

186.1

180.1

172.8

194.3

181.0

174.4

194.3

181.0

174.7

194.1

180.9

174.7

194.7

182.3

174.8

180.7

176.2

168.7

standard

207.8

200.1

190.0

206.1

199.1

190.3

192.0

184.8

175.4

190.9

184.7

176.3

192.0

185.2

174.8

190.6

182.4

174.6

190.9

182.9

174.6

190.9

182.0

174.6

190.9

183.3

174.8

186.5

186.0

177.6

205.1

196.1

186.9

204.2

196.1

186.6

204.1

196.0

186.4

206.0

196.2

187.2

192.1

181.0

176.6

215.0

210.5

204.3

210.3

;::.:

.

192.6

192.1

186.1

192.6

192.1

186.6

192.6

192.2

186.3

192.5

192.0

186.1

192.5

190.9

182.4

192.5

192.1

188.5

192.5

192.1

188.3

186.7

186.4

186.1

210.1

197.0

194.4

204.2

196.9

193.3

204.3

197.5

194.4

210.2

198.6

194.2

190.8

190.1

183.0

223.1

216.2

211.5

210.6

210.1

206.1

192.6

192.2

186.4

192.6

192.2

186.4

192.6

192.1

184.4

192.5

192.1

190.2

192.4

190.6

188.4

192.6

192.2

188.4

192.5

190.9

188.4

186.7

186.5

186.2

210.5

206.2

198.3

204.5

204.0

197.8

204.6

204.1

197.9

210.4

204.4

198.2

192.6

192.3

184.1

223.2

217.9

214.0

210.7

210.3

209.8

192.7

192.4

192.1

192.7

192.4

192.1

192.7

192.4

192.1

192.7

192.4

192.1

192.7

192.3

192.0

192.8

192.5

192.2

192.8

192.5

192.2

186.7

186.5

186.2

210.5

210.1

197.4

204.6

204.2

195.9

204.6

204.2

196.9

210.6

210,2

200.3

192.8

192.5

192.2

Girls-chronological age in years

12 13 14 15 16 17

Bone-specific skeletal age in months—female

equivalent

152.5

143.8

134.7

152.3

143.5

133.9

144.8

136.9

132.7

146.8

137.6

132.3

143.5

136.2

130.4

143.6

136.8

130.2

144.4

136.4

131.2

143.4

136.5

130.7

143.4

136.3

130.8

148.3

140.5

134.3

148.6

140.8

134.2

148.8

142.1

134.6

148.6

142.0

134.3

148.8

142.0

134.4

143.3

136.7

131.6

164.7

154.2

146.1

166.1

153.6

145.3

151.7

145.3

136.7

152.2

146.1

137.0

150.4

143.4

136.2

149.1

143.2

136.8

150.0

143.8

136.5

149.0

143.1

136.6

149.0

143.1

136.4

155.1

148.1

140.8

164.3

149.0

142.4

163.3

149.0

142.4

164.1

148.9

142.7

163.4

150.3

142.8

148.7

143.2

136.7

180.8

170.1

159.0

179.1

170.1

159.6

162.0

152.8

143.4

160.8

152.7

144.3

162.0

153.2

141.8

159.6

150.4

141.6

159.9

150.9

142.6

158.9

150.0

141.6

159.8

151.3

141.8

155.5

155.0

145.6

176.2

166.1

155.8

174.2

166.1

154.6

175.1

166.0

154.8

~;;.:

155:2

160.1

149.0

143.6

192.0

184.5

175.6

183.6

179.8

171.6

162.6

162.1

154.2

162.6

162.1

155.2

162.6

162.2

154.3

162.0

161.0

154.1

162.0

159.9

150.4

161.5

161.1

156.5

162.0

161.2

156.3

155.7

:;;.;

.

184.1

167.0

164.4

174.2

166.9

162.3

175.3

167.5

164.4

183.4

168.2

162.4

158.8

158.1

151.0

200.2

193.2

186.0

184.2

183.2

179.1

162.6

162.2

154.8

162.6

162.2

155.8

162.6

162.1

152.4

162.0

161.2

159.2

161.8

159.6

157.4

161.6

161.2

156.4

162.0

159.8

156.4

155.7

155.5

155.2

184.5

178.2

168.3

174.5

174.0

167.8

175.6

175.1

167.9

183.8

175.4

167.4

160.6

160.3

152.1

200.4

194.9

190.0

184.4

183.6

182.8

162.7

162.4

162.1

162.7

162.4

162.1

162.7

162.4

162.1

162.4

161.8

161.2

162.4

161.6

161.0

161.8

161.5

161.2

162.6

162.0

161.4

155.7

155.5

155.2

184.5

184.1

167.4

174.6

174.2

165.8

175.6

175.2

166.9

184.2

183.4

170.3

160.8

160.5

160.2

75
Table 8, Selected percentiles in the distribution of bone-specific skeletal ages for each of the

31 hand-wrist bones of youths, by chronological age in years at last birthday and sex: United

states, 1966-70—con.

—.

Hand-wrist bone and percentile

Adductor sesamoid:

P75 -------------------------------------------

Pm-------------------------------------------

P~--------------------------------------------

Flexor sesarooid:

p75-------------------------------------------

P50-------------------------------------------

P 25-------------------------------------------

Proximal phalanx I:

P75 --------------------” ----------------------

P5(J -------------------------------------------

P25 -------------------------------------------

Proximal phalanx II:

p,=-------------------------------------------

p50-------------------------------------------

p 2$ -------- --------- -------- ----.--- .-------- --

-Proximalphalanx 111:

P75 --------------------------------”----------

P50-------------------------------------------

P=-------------------------------------------

Proximal phalanx IV:

P75-------------------------------------------

P~--------------------------------------------

P*5-------------------------------------------

Proximal phalanx V:

P 75 --------- --------- --------- ----------------

Pw-------------------------------------------

p25-------------------------------------------

Middle phalanx II:

P75 ------------------------------------------- p50-------------------------------------------

P~5-------------------------------------------

Middle phalanx III:

P75-------------------------------------------

P51J -------------------------------------------

P25-------------------------------------------

Middle phalanx IV:

P 75-------------------------------------------

P 50-------------------------------------------

P 5-------------------------------------------

Mid~le phalanx V:

P75 -------------------------------------------

P50-------------------------------------------

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

Di!~~l phalanx I:

P7~-------------------------------------------

P 50-------------------------------------------

P 25-------------------------------------------

Distal phalanx II:

P 75-------------------------------------------

P~o-------------------------------------------

Pz5-------------------------------------------

Distal phalanx III:

P75 -------------------------------------------

P50-------------------------------------------

P25-------------------------------------------

Distal phalanx IV:

P 75-------------------------------------------

PCJJ-------------------------------------------

P ~--------------------------------------------

Distal phalanx V:

P7&-------------------------------------------

P~o-------------------------------------------

P2~-------------------------------------------

Boys—chronological age in years

=T=7=11++7

BOne-SDeCifiC skeletal age in months—male

164.3

160.0

155.8

168.7

164.6

160.6

155.8

138.7

127.0

154.8

138.9

128.0

156.0

139.6

127.9

154.6

139.5

127.2

153.9

140.0

128.2

156.3

140.2

129.8

i56.2

140.1

129.7

154.8

138.8

128.9

154.9

140.0

129.5

154.7

138.8

126.4

155.0

138.7

126.7

154.9

138.7

126.8

154.8

138.8

126.9

154.7

139.3

126.7

170.9

164.6

158.4

174.8

168.4

160.9

172.1

160.5

144.4

172.3

160.7

146.6

172.7

160.6

147.2

172.9

160.2

144.9

;;;.:

146:0

172.3

160.1

144.9

172.2

160.2

145.0

172.5

158.9

144.5

172.4

159.5

144.4

168.9

158.3

144.5

168.9

159.8

144.9

169.0

159.4

144.9

170.0

159.2

144.8

170.0

158.9

144.9

standar~

178.1

170.6

164.1

178.0

172.4

166.5

180.9

174.2

164.8

182.2

174.5

164.4

182.1

174.5

164.4

182.1

;;;.:

.

181.9

174.7

164.4

182.6

17&.6

164.2

182.6

:;:.g

.

182.7

174.8

164.4

182.5

174.6

164.4

177.0

170.9

162.3

177.4

171.7

162.4

177.2

171.5

162.4

177.7

171.9

162.4

177.6

171.8

162.3

181.5

176.2

168.6

180.9

176.1

168.9

191.5

181.1

175.1

190.7

182.2

175.0

191.2

182.5

175.5

190.8

182.2

175.8

190.9

182.4

175.5

190.0

182.5

175.0

191.4

182.6

176.1

190.3

182.8

176.1

189.8

182.6

176.1

183.7

177.0

170.1

182.1

177.4

170.2

180.5

177.0

170.4

181.6

177.2

170.2

181.0

177.3

169.8

188.0

176.8

168.5

186.6

176.7

170.1

196.5

188.8

177.8

200.5

188.4

177.8

196.6

188.2

IJ7.8

200.2

188.3

178.7

204.4

188.1

178.4

196.5

188.5

180.2

196.3

189.4

180.4

196.0

188.9

180.5

196.2

188.5

180.4

186.5

182.1

174.6

186.3

180.5

174.7

186.3

179.3

174.5

186.0

180.8

174.5

186.2

180.8

174.8

192.3

186.4

176.9

192.4

190.3

180.4

210.3

200.1

192.0

204.4

198.0

190.9

204.4

198.6

190.5

202.3

196.7

190.1

204.4

196.9

189.4

204.3

196.4

188.4

204.4

;;$ ;

.

xl;.;

189:5

204.3

194.9

188.5

186.9

:;:.:

.

186.9

186.3

182.6

186.9

186.4

182.5

186.6

186.2

182.2

186.6

186.1

182.2

76
Table 8. Selectedpercentilesin the distributionof bone-specificskeletalages for each of the

31 hand-wristbones of youths, by chronologicalage in years at last birthdayand sex: United

Statea,1966-70—Con.

Girls—chronologicalage in years

12 13 14 15 16 17

Bone-specificskeletalage in months—male

standard

176.6

168.:

163.1

178.2

170.E

166.(

182.3

L75.5

168.7

183.3

176.3

168.2

L84.C

176.6

168.3

184.2

L77.2

168.4

L83.6

L,77.3

L68.4

L84.9

1.76,9

L67.9

L84.8

176.9

168.1

186.1

L77.I

L67.4

L85.9

L77.O

168.0

178,5

L73.3

164.7

180.2

L73.2

164.5

178.3

.74.0

.64.5

!80.2

.74.1

.64.2

.80.3

.74.2

.64.2

180.8

174.8

166.9

180.8

176.0

170.4

194.2

183.9

175.9

193.5

182.8

176.1

193.0

183.0

176.2

194.1

183.9

176.4

193.7

183.4

176.4

193.3

184.2

176.3

194.2

184.5

176.7

19&.1

186.0

176.8

192.7

184.4

176.6

186.4

177.9

172.0

186.3

180.2

172.6

186.1

178.0

172.9

183.3

178.7

172.6

184.3

178.2

172.5

186.7

180.5

171.7

186.9

180.5

174.5

210.2

196.1

184.7

204.4

196.5

184.1

204.4

197.3

184.8

204.4

196.7

184.8

204.4

197,4

184.5

204.3

194.6

184,7

204.3

195.0

186.3

204.3

195.2

186.9

204.3

194.3

184.8

186.8

186.2

177,0

186.8

186.3

180.1

186.8

186.2

177.8

186.5

186.0

177.2

186.5

186.0

177.7

186.7

180.7

174.7

186.3

180.7

180.1

210.5

210.1

196.9

204.6

204.2

194.5

204.6

204.2

196.6

204.6

204.2

196.4

204.6

204.3

196.9

204.6

204.1

195.5

204.5

204.1

194.9

204.5

204.1

194.6

204.5

204.1

192.3

204.1

186.7

186.3

204.2

186.7

186.3

204.2

186.7

186.3

186.7

186.4

186.2

186.7

186.4

186.2

190.2

180.8

176.2

192.1

186.1

180.2

210.6

210.2

204.8

204.7

204.4

204.0

204.7

204.2

204.1

204,7

204.4

204.1

204.7

204.4

204.1

204.7

204.4

204.1

204.7

204.4

204.0

204.7

:()).:

.

204.7

204.4

204.1

186.9

186.6

186.3

186.9

186.6

186.3

187.0

186.6

186.3

186.8

186.5

186.2

186.8

186.5

186.2

192.4

189.4

180.5

192.t

192.2

180.7

210.7

210.3

210.c

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

204.7

204.5

204.2

186.8

186.5

186.3

186.8

186.5

186.3

186.8

186.5

186.3

186.7

186.5

186.2

186.7

186.5

186.2

Girls—chronological age in years

12 13 14 15 16 17

Bone-specificskeletalage in months-female

equivalent

144.6

136.9

133.0

146.2

138.6

134.8

150.3

142.5

136.4

150.6

143.3

136.2

152.0

144.8

136.6

152.2

145.2

136.7

151.6

145.3

136.4

152.9

144.9

135.9

152.8

144.9

136.0

154.1

145.1

135.4

153.9

145.0

136.5

146.5

141.3

134.4

148.2

141.2

133.5

146.3

142.0

134.2

148.2

142.1

134.1

148.3

142.1

134.1

148.8

142.8

134.9

148.8

144.0

138.4

164.2

151.9

142.9

163.2

150.4

143.1

163.0

151.0

144.6

164.1

151.9

144.7

162.7

151.4

144.4

163.3

152.2

144.3

163.2

152.5

L44.7

163.1

154.0

144.8

162.4

152.4

144.6

153.4

145.9

140.0

154.3

148.2

140.6

153.2

146.0

140.9

151.3

146.7

140.6

152.3

145.2

139.8

154.7

148.5

139.7

154.9

148.5

142.5

183.4

166.1

152.7

174.4

166.0

151.1

176.4

167.3

152.8

176.4

166.7

152.8

174.8

166.4

152.5

175.3

164.6

152.7

175.3

164.0

154.3

175.3

164.4

154.9

174.6

164.3

152.8

153.8

153.2

145.0

154.8

154.3

148.1

154.6

153.4

145.8

154.0

153.0

145.2

154.5

154.0

144.7

154.7

148.7

142.7

154.3

148.7

148.1

184.0

183.2

166.9

174.6

174.2

163.8

176.6

176.2

166.6

176.6

176.2

166.4

175.2

174.6

165.9

175.6

175.1

165.5

175.5

175.1

163.9

175.5

175.1

163.6

175.0

174.1

161.6

153.7

153.3

154.7

154.3

;;:.j

.

154.4

153.8

153.4

154.7

154.4

154.2

159.2

148.8

144.2

161.2

154.1

148.2

184.2

183.4

176.6

174.7

174.4

174.0

176.7

176.2

176.1

176.7

176.4

176.1

175.4

174.8

174.2

175.7

175.4

175.1

175.7

175.4

175.0

175.7

175.4

175.1

175.4

174.8

174.2

153.9

153.6

153.3

154.9

154.6

154.3

155.0

154.2

153.6

154.6

154.0

153.4

154.8

154.5

154.2

161.8

158.4

148.5

162.2

161.4

148.0

184.4

183.6

183.0

174.7

174.5

174.2

176.7

176.5

176.2

176.7

176.5

176.2

175.4

175.0

174.4

175.7

175.5

175.2

175.7

175.5

175.2

175.7

175.5

175.2

175.4

175.0

174.4

153.8

153.5

153.3

154.8

154.5

154.3

154.6

154.0

153.6

154.4

154.0

153.4

154.7

154.5

154.2

77
Table 9. Selected percentiles, mean and standard deviations (sX) 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 youth’s, bychronological age inyears at last

birthday and sex: United States, 1966-70

Chronological

age and sex

12

13

14

15

16

17

Boys

yeara ---------------------

years ---------------------

yeara ---------------------

years ---------------------

years ---------------------

years ---------------------

Girls

12

13

14

15

16

17

—

years ---------------------

years ---------------------

years ---------------------

years ---------------------

years ---------------------

years ---------------------

Percentile point

P95 P75 P50 P~~ PIj Mean s~

Bone-specific skeletal age range

in months—male standard

30.2

27.5

26.6

24.8

28.0

25.4

26.9

30.1

30.8

34.2

34.8

34*5

20.4

18.7

16.9

15.6

15.0

12.4

18.8

18.9

18.5

16.5

10.7

14.3

15.8

14.5

12.4

10.8

8.8

5.4

14.1

12.8

10.7

6.7

2.3

2.0

12.3

10.9

8.9

6,7

3.8

0.9

10.5

8.7

4.9

1.4

0.5

0.5

7.1

6.3

4.7

1.8

0.4

0.2

5.0

2.6

0.6

0.2

0.1

0.1

16.3

15.0

13.1

11.5

10.3

7.7

14.8

14.1

12.4

10.3

7.6

8.3

6.83

7.00

6.77

7.34

8.94

8.76

7.42

8.90

10.22

11.39

12.25

11.86

78
Table 10. Median age in months at

youths 12-17 years chronological

epiphyseal fusion for selected hand-wrist bones of

age at last birthday by sex: United States, 1966-70

Hand-wrist bone

Radius.-----------------------------

Ulna---------------------------------

Metacarpal I-------------------------

Metacarpal II------------------------

Metacarpal III-----------------------

Metacarpal IV------------------------

Metacarpal V-------------------------

Proximal phalanx I-------------------

Proximal phalanx II------------------

Proximal phalanx III-----------------

Proximal phalanx IV------------------

Proximal phalanx V-------------------

Middle phalanx

Middle phalanx

Middle phalanx

Middle phalanx

Distal phalanx

Distal phalanx

Distal phalanx

Distal phalanx

Distal phalanx

II--------------------

III-------------------

Iv--------------------

v------- ------- -------

1 -------- -------- -----

11--------------------

111-------------------

IV--------------------

v----------------.----

Median chronologicalage in months for:

Boys

*

*

190

199

199

198

199

196

191

193

193

191

194

197

197

196

188

188

189

187

188

Girls

*

194

166

178

177

178

179

168

168

169

169

168

168

169

169

168

161

161

161

161

161

*Estimates of median age not p?ssible or not sufficiently reliable for publication.

The radius had reached the “adult” stage for only 26 percent of boys and 53 percent of

girls and the ulna in only 51 percent of boys by 17.9 years.

79
Table 11. Selected skeletal maturity findings for children age 6-11 years in 1963-65 who were again examined as yautha age

12-17 years in 1966-70 (32 percent of the,youth axaminees): United States, 1963-70

Skeletal maturity

Skeletal age in months

As children 6-11 years in 1963-1965:

Mean----------------------------------

*Z------------------------------------

As youths 12-17 years in 1966-1970:

Mean----------------------------------

~x-------------------------------------

Number of bones ossifying (not adult)

As children 6-11 years in 1963-1965:

Mean ---------------------------------

.$~-----------------------------------

As youths 12-17 years in 1966-1970:

Mean---------------------------------

~ -.---------------------------------

Number of adult bones

As children 6-11 years in 1963-65:

Mean----------------------------------

-%------------------------------------

As yauths 12-17 years in 1966-1970:

Mean----------------------------------

s=------------------------------------

Bone-specific skeletal age range

As children 6-11 years in 1963-1965:

Mean----------------------------------

*:------------------------------------

As youths 12-17 years in 1966-1970:

,J.&n ----------------------------------

.s~------------------------------------

Radius-skeletal age

As children 6-11 years in 1963-1965:

Mean----------------------------------

s~------------------------------------

As youths 12-17 years in 1966-1970:

Mean----------------------------------

=x------------------------------------

Ulna-skeletal age

As children 6-11 years in 1963-1965:

Mean ---------------------------------

Sz-----------------------------------

As youths 12-17 years in 1966-1970:

Mean---------------------------------

s~ -----------------------------------

Scaphoid-skeletal age

As children 6-11 years in 1963-1965:

Mean----------------------------------

s~ ------------------------------------

As youcha 12-17 years in 1966-1970:

Mean----------------------------------

SF------------------------------------

BOYS—chronological age in”1966-1970

12

years

9$3.7

1.68

139.7

0.93

27.S

0.06

29.2

0.06

lW

23.9

0.73

16.8

0.43

101.9

1.29

139.3

1.01

103.0

1.07

139.5

0.96

103.8

1.23

L~S;~

13

years

107.5

2.00

158.2

0.90

28.3

0.04

28.9

0.23

OX

21.0

0.58

15,7

0.59

!10.5

0.93

.57.s

0.82

110.S

0.85

157.6

0.88

111.6

0.79

!54.6

0.96

14

years

118.7

1.19

173.0

0.96

28.6

0.03

26.3

0.44

10.8

0.58

20.6

0.68

13.2

0.35

119.6

1.23

172.7

0.94

118.4

1.25

172.3

0,88

119.6

1.14

l~6b;

15

years

125.C

I.&e

187.2

1.9C

28.S

0.06

17.5

1.07

lB,O

1.12

21.6

0.94

10.5

0.64

124.6

1.33

L87.9

1.87

124.0

1.24

186.7

1.82

125.3

0.97

171.2

2.39

16

years

130.4

30.22

193.3

$3.67

28.8

6.45

12.0

7.97

23.4

8.98

16.8

6.33

9.2

2.80

L30.6

30.39

L92.8

k3.60

L30.4

10.03

194.5

i4.11

L32.4

10.62

177.5

38.86

17

fears

Girls—chronological age in 1966-1970

12

rears

115.:

1.5!

L74.;

1.02

28.6

0.09

25.6

0.57

12.5

0.96

22.3

0.55

14.4

0.52

.13.8

1.33

.73.4

1.09

.13.6

1.42

.73.1

1.10

.17.2

1.19

.66.7

0.83

13

years

130.1

2.4c

187.1

0.81

29.2

0.07

19.2

0.58

0%

15.7

0.41

22.9

0,52

14.0

0.62

128.4

1.94

L85.9

0.91

L28.3

1.93

185.4

0.93

L29.O

1.72

L74.8

1.14

14

years

145.0

2.32

197.8

0.68

29.5

0.10

11.6

0.61

o%

21.2

0,53

24.5

0.65

12.5

0.68

.46.1

L.43

.;7i;

.43.6

1.39

.96.2

0.70

:43,0

1.92

.79.3

1.87

15

yearz

156.!

1.7(

206.:

0.7:

29.2

0.13

O?ii

0.7

0.14

26.3

0.2E

24.C

1.15

10.3

0.65

156.2

0.87

210.4

0.73

154.1

1.03

204.6

0.55

148.2

2.39

177.6

B8.83

16

years

159.2

36.4E

207.C

46.62

27.0

6.35

.4?;:

2%;

26.0

7.39

27.4

7.35

4’?i;

166.0

38.02

208.0

$6.83

155.4

)6.65

!04.4

54,67

LOO.2

37.68

17

years

80
Table 11. Selected skeletal maturity findings for children age 6-11 years in 1963-65 who were again examined as youths age

12-17 years in 1966-70 (32 percent of the youth examiners): United States, 1963-70—Con.

Skeletal maturity

Metacarpal I-skeletal age (months)

As children 6-11 years in 1963-1965:

Mean----------------------------------

ax------------------------------------

AsMyo#hs 12-17 yeara in 1966-1970:

----------------------------------

s;------------------------------------

Pisiform-skeletal age

Aa children 6-11 years in 1963-1965:

Mean----------------------------------

~x------------------------------------

AsMggw#hs 12-17 years in 1966-1970:

----------------------------------

W ------------------------------------

Adductor sesamoid-skeletal age

As children 6-11 years in 1963-1965:

Mean----------------------------------

Q

------------------------------------

As youths 12-17 years in 1966-1970:

Mean----------------------------------

SF------------------------------------

Flexor sesamoid-skeletal age

As children 6-11 years in 1963-1965:

Mean----------------------------------

W-------------------------------------

AsMyo;t~ 12-17 years in 1966-1970:

- --------------------------------

% ------------------------------------

Proximal phalanx II-skeletal age

Aa children 6-11 years in 1963-1965:

Mean----------------------------------

s;------------------------------------

As youths 12-17 years in 1966-1970:

Mean----------------------------------

% ------------------------------------

Middle phalanx II-skeletal age

As children 6-11 years in 1963-1965:

Mean----------------------------------

% ------------------------------------

AsM~ths 12-17 years in 1966-1970:

----------------------------------

s~------------------------------------

Distal phalanx 11-skelatal age

AaM;~~ldren 6-11 years in 1963-1965:

----------------------------------

Sax-----------------------------------

AsM~ths 12-17 years in 1966-1970:

----------------------------------

*Z------------------------------------

BOYS—chronological age in 1966-1970

12

years

100.3

1.32

137.s

0.95

l;6i;

140.8

0.99

159.2

0.54

165.0

1.22

1;36;

139.9

0.94

105.1

1.07

141.1

0.95

105.5

1.09

139.2

1.02

13

years

109.4

0.76

156.2

0.s4

11S.6

0.80

156.0

0.75

159.0

79.61

165.8

0.64

169.0

0.95

l~2;#

158.8

0.95

113.2

0.89

159.1

0.99

112.2

0.69

157.0

1.02

14 15

years years

118.0 125.0

1.21 1.65

169.1 175.0

0.94 1.66

I

124.8 129.6

1.40 1.60

166.8 171.2

1.24 2.17

155.8 156.4

1.35 1.15

171.1

0.71

174.7

1.12

15s.5 160.6

50.13 1.31

120.2 126.6

1.14 1.79

1;16:180.2

1.81

121.6 128.0

1.19 1.42

1;16: 181.2

2.0s

1:16; 127.1

1.69

168.3 173.S

0.90 1.33

16

years

129.3

29.92

177.2

68.84

132.5

42.68

169.5

19.85

176.7

68.53

176.2

68.36

131.0

30.23

181.7

70.51

132.9

30.56

180.3

69.89

130.0

30.27

177.4

88.79

17

years

Girls—chronological age in 1966-1970

12

years

117.4

1.43

169.9

0.85

124.6

1.03

167.2

0.75

155.8

0.98

169.3

0.83

161.7

1.05

171.1

0.77

l:oi;

174.7

0.88

120.9

1.39

1;5~;

118.8

1.23

170.6

1.00

13

years

131.7

1.86

177.s

0.59

134.7

1.97

174.8

0.79

158.9

0.75

1;4;$

162.2

0.s0

175.7

0.66

1;5;:

184.1

0.95

136.1

1.80

184.7

1.00

133.1

1.79

179.6

1.17

14

years

147.8

1.53

180.3

0.s3

148.4

1.57

181.4

1.62

161.2

0.51

179.3

1.34

165.3

0.77

181.1

1.01

1;2<:

193.1

0.96

152.6

1.44

1:3;:

149.4

1.36

183.9

1.24

15

years

156.6

1.07

184.9

0.56

156.4

1.17

184.0

58.28

164.6

0.77

1s3.0

2.66

167.4

0.99

1S1.8

40.7s

162.0

0.94

199.7

1.42

162.0

1.02

199.9

1.40

158.8

1.34

186.8

1.31

16

yeara

156.0

35.78

152.5

35.27

168.4

65.65

166.0

17.37

161.2

36.73

200.0

41.42

161.8

37.19

200.0

41.42

155.9

36.14

186.0

31.52

17

{eara

81
Table 12. Percent distributionof increase in skeletalmaturation (hand-wrist)between first and

second examinationwithin designated time intervalsbetween the two examinationsfor boys and

girls in both the Health Examination Surveys of 1963-65 and 1966-70

Increase in

skeletal age

between first and

second examimtion

Boys

Totall-----------------

Under 30 months--------------

30-35 months-----------------

36-41 months-----------------

42-47 months-----------------

48 months or more------------

Girls

Under

30-35

36-41

42-47

Tota12-----------------

30 months--------------

months-----------------

months-----------------

months-----------------

48 months or more------------

Increase in chronologicalage between

first and second examination

Total Under

30 months

100.0

1.9

18.4

25.5

18.0

36.2

100.0

1.7

16.9

27.1

19.4

34.9

30-35 36-41 42-47 48 months

months months months or more

Percent distribution

100.0

38.0

28.6

14.3

19.1

100.0

29.4

11.8

29.3

11.8

17.7

100.0

25.9

15.7

14.7

14.7

29.0

100.0

9.4

21.3

21.9

25.5

21.9

100.0

20.9

10.6

10.6

18.2

39.7

100.0

4.5

10.3

18.1

21.3

45.8

lExcl~des32 boys without usable radiographs in both surveYs.

ZExcl~des39 girls without usable radiographs in both surveys.

100.0

8.0

14.1

11.1

13.6

53.2

100.0

3.1

2.1

7.7

7.7

79.4

100.0

5.4

5.2

10.5

12.5

66.4

100.0

1.2

2.3

2.3

8.0

86.2

Skeletal

age increase

from first

to second

examination

100,0

14.3

10.6

1105

14.2

49.4

10000

4.3

7.8

1104

14.6

61.9

82
Table 13. Percent distribution of the lag of skeletal age (hand-wrist) behind chronological age at the

time of the first and second examination for boys and girls in both the Health Examination Surveys of

1963-65 and 1966-70

Skeletal age leas

chronological age at

second examination

Boys

Totall----..--------------

Less than -24 months------------

-13 thru -24 months-------------

-1 thru -12 months--------------

O thru 11 months----------------

12 months or more---------------

Skeletal age less chronological age at first examination

T

100.0 11.7

13.7 $?

16.3

26.2 3:3

26.4

17.4 ;:;

13 through

-24 months

32.9

6.8

6.5

9.5

6.4

3.7

-1 through

-12 months

35.6

2.4

1;:;

10.8

5.8

0 through

11 months

15.7

0.5

1.1

2.9

2::

12 months

or more

4.1

0.2

0.3

R

Skeletal age less chronological age at first examination

Tota1

Less than -1 through O through 12 through 24 through 36 months

-12 months -12 months 11 months 23 months 35 months or more

Girls

Tota12-------------- 100.0 3.7 13.0 29.6 26.0 21.6 6.1

Less than 12 months------- 0.6 0.2 0.1

-1 thru -12 months-------- 2.4 ::; 1.2

0 thru 11 months---------- 10.7 1.7 ::: 0.5

12 thru 23 months--------- 31.3 0,8 ;:: 12.8 ::: :::

24 thru 35 montha--------- 37.5 0.1 2.6 9.3 11.4 1%:: 1.8

36 months or more--------- 17.5 0.1 0.6 3.0 3.7 6.2 3.9

l~cludea 32 boys without usable radiographs in both surveys.

?.Excludes 39 girls without usable radiographa in both surveys.
APPENDIX I

STATISTICAL NOTES

The Survey Design

The sample design for the first three programs or

Cycles I-HI of the Health Examination Survey has been

essentially similar in that each has been a multi-stage,

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),

eligibIe persons, and finally, the sample person.

The 40 sample areas and the segments utilized in

the design of Cycle 111were the same as those in Cycle

II. Previous reports describe in detail the sample design used for Cyble 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.617

Requirements and limitations placed on the design

for Cycle III, similar to those for children in Cycle II,

were that:

1.

2.

3.

4.

5.

The target population be defined as the civilian

noninstitutionalized population of the United

States, including Alaska 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 those 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 examination within the specially

constructed mobile examination center be between 2 and 3 hours.

Ancillary data be collected on specially designed

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 findings within broad geographic regions

and population density groups as well as age,

sex, and limited socioeconomic groups for the

total sample.

The sample was drawn jointly with the 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 contagious coumies. These PSU’S were grouped into 40

strata, so that 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-Kisb

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 are small well-defined 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, aged 5-9, in the ED at the time of the

1960 census. A sample of 20 ED’s in the sample PSU

were 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_t.heR made. .—-

Because of the 3-year time interval between Cycle

II and Cycle HI, the Cycle 111frame had to be supplemented for new construction and to compensate for

segments where housing was partially 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, subsampling was done by

85
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 HI, as in Cycle H, 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 111,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 sonewhat 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 United States 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 HI 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 previously ;6~7*l1s those

additional measures specifically related to skeletal age

are outlined earlier in this report.

Reliability

While 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 1117describes 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 with

known United States population figures by color and sex

within single years of age 12 through 17 for the youth’s

survey.

In 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.llg 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 self-weighting 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 nonrespondents 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

which 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 United States 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 upwards or downwards 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 useable radiographs were 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.

86
Table I. The number of youths whose radiographs

were assessed; the number not assessed refers

to youths who were examined but whose radiogra~hs were missing or of poor quality:Health

Examination Survey, 1966-70

Age

12

13

14

15

16

17

Total --------

years -----------

years -----------

years -----------

years -----------

years -----------

yeara -----------

Assessed

(6,736)

Boys Girls

;;; 543

582

617 584

610 503

555 528

487 462

Sampling and Measurement Error

Not

assessed

(32)

8

3oys Girls

=4=

In the present report, reference has been madeto

efforts to minimize bias and variability of measurement techniques.

The probability design ofthesurvey makespossible

the calculation of sampling errors. The samplingerror

is used here to determinehowimprecise thesurvey test

results maybe because theycomefroma 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 Ieast three reasons: (l) measurement error and

“pure’’sampling error are confounded inthedata—itis

not easy.tofindaprocedurewhichwilleither completely

include both or treat one or the other separately, (2) the

survey design andestimation procedureare complexand

accordingly require computationally involved techniques

for the calculation of variances, and (3) from the survey

are coming thousands of statistics, manyforsubclasses

of the population for which there are asmall number of

cases. Estimates of sampling error are obtained from

the sample d~ta and are themselves subjecttosampling

error which maybe large when the numberof cases in

a cell is smaller even occasionallywhenthe number of

cases is substantial.

Estimates of approximate sampling variability for

selected statistics used in this report are included in

the detailed tables. These estimates have beenprepared

by a replication technique which yields overall variability through obeervationof variability among random

subsamples of the total sample. The method reflects

both I!pure” sampling variance snd a part of the measurement variance.

In accordance with usual practice, the interval

estimate for any statistic may be considered the range

within one standard error of the tabulated statistic, with

68 percent confidence; ortherange within twostandard

errors of the tabulated statistic, with95percent 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 given by the

formula Sd= (S: + .$)Y2 where .5X and SY are the sampling errors, respectively, of x and y. Of course, where

the two groups or measures are positively or negatively

correlated, this will give an overestimate or underestimate, respectively, of the actual standard error.

Small Numbers

In some tables magnitudes are shown for cells for

which the sample size is so small that the sampling error

Table 11. Number of boys and girls for whom

skeletal age assessments were made on each of

the 31 hand-wrist bones: Health Examination

Survey, 1966-70

Bone

Radius -------------

Ulna ---------------

Cavitate -----------

Hamate -------------

Tri_quetral ---------

Lunate -------------

Scaphoid -----------

Trapezium ----------

Trapezoid ----------

Metacarpal I-------

Metacarpal II ------

Metacarpal III -----

Metacarpal IV------

Metacarpal V-------

Proximal phalanx IProximal phalanx

II----------------

Proximal phalanx

III---------------

proximal phalanx

IV----------------

Proximal phalanx VMi.ddle phalanx II--

Middle phalanx IIIMiddle phalanx IV--

Middle phalanx V---

Distal phalanx I---

Distal phalanx II--

Distal phalanx IIIDistal phalanx IV--

Distal phalanx V---

Pisiform -----------

Adductor sesamoid--

Flexor sesamoid----

Radi.oopaque, not

adult

Boys

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

23339

2,335

2,298

2,307

13773

1,511

1,095

Girls

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

Adult

Boys

11

11

1

;

3

;

2

1

1

1

;

2

1

1

1

1

1

1

1

1

;

2

;

166

574

,052

S7
may be several times as great as the statistic itself. there were a few of inadequate quality to permit assessObviously in such instances the statistic has no meaning ment of all bones. In general, these would have been

in itself except to indicate that the true quantity is bones that became radio-opaque recently or bones near

small. Such numbers, if shown, have been included in the margin of the radiographic field. The number of

the belief that they may help to convey an impression youths for whom bone- specific skeletal ages were asof the overall story of the table. signed and the numbers in which particular bones were

Among the 6,736 children with useable radiographs, adult are shown in table II.

000

88
APPENDIX II

RELIABILITY OF ASSESSMENTS

To provide the basis for determining the level of reliability of the bone-specific skeletal age assessments

made by the nine medical students at Case Western Universit y from hand-wrist radiographs of the 12-17 year

old youths examined in the Health Examination Survey of

1966-70, a randomly selected sample of one in 23 radiographs was reassessed by the same reader and approximately one in 20 independently randomly selected

radiographs were reassessed by another reader, as described previously. All nine readers, before starting

these final 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 self-replicate assessments and 301 cross-replicate assessments were

made. Each reader made approximately the same

number of self-replicate and 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 his original and self-replicate assessments ranged from 0.2 to 1.7 months combining

data from both sexes. For the 28 bones that ossify relatively early, tbe mean differences range from 0.2 to

1.6 months among the nine readers (table III).

A consistently high level of agreement in bonespecific 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 cross- replicate difference for all

31 hand-wrist bones was 0.2 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 substantially slightly

less—O.l month —and ranged from 0.8 to 2.4 months

among the individual readers.

The aspects considered include consistency within

observers (intraobserver differences), comparability

between observers (interobserver differences), and

differences resulting from variations in the way the

Table III. Mean difference i.n cross- and self -replicate assessments of bone-specific skeletal

ages from hand -wrist radiographs of examinees 12-17 years old at last birthday, by reader:

Health Examination Survey, 1966-70

Reader

All readers ------------------------------------

Reader 21--------------------------------------------

Reader 22--------------------------------------------

Reader 24--------------------------------------------

Reader 25--------------------------------------------

Reader 26--------------------------------------------

Reader 27--------------------------------------------

Reader 28--------------------------------------------

Reader 29--------------------------------------------

Reader 30--------------------------------------------

I I

Selfreplicates

31

bones

-0.1

1.6

-1.2

-1.7

0.5

-0.2

-0.3

0.3

-:::

Cross- Number of

replicates films

replicated

I

28 31

bones bones

t

-0.1 -0.2

I

-H!

-1.6

0.4

-0.2

-0.3

0.2

-M

0.7

-2.3

-1.7

2.6

-0.8

-1.5

1.0

-1.0

-1.3

!

I

28

bones ‘elf- Cross-

-R

-1.6

-::2

-1.7

1.3

-0.8

-1.0

36

36

21

66

44

44

44

30

30

32

30

20

56

27

28

I I

89
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 to 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: 27!!Through 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 as sessments

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 Moore120 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 Ages

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 months 121and mean differences ranging from 1.2

to 6.6 months have been reported, 117,122-12s in addition

to variable errors of 1.4 to 4.2 months. 1’26,127The

median intraobserver differences range from zero to 4

months,128J2g 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’s u 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.1z4JsOJsl In addition, a root

mean square of 6.2 months and confidence limits of 7.4

months have been reported. 121J 25 Reported incidence

of particular interobserver differences indicate that the

medians were less than 3 months for the study by

Hansman and Maresh132 and less than 6 months for the

study by Moed et aL128

Bone-Specific Skeletal Ages

Moore 120reported interobserver differences that

were less 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. 123*126However, the range of maturity between the bones of hand-wrist influences the replicability of overall but not bone-specific asseas-

~ents. 123,124 The quality of radiographs (exposure,

positioning) has no effect on replicability within the

range that is common in research studies,124but unusually poor radiographic quality does reduce replicability.l 2GThe method by which the Greulich-Pyle Atlas

is uskd has an effect. Maresh 65 reported a technical

error of 3.0 months between overall assessments and

those obtained as the means of bone-specific skeletal

ages.

—000

*U.S. GOVERNMENT PRINTING OFFICE: 1976– 241-180:1

90
series1.

Sera”es2.

Sm”es 3.

Series 4.

VITAL AND HEALTH STATISTICS PUBLICATIONS SERIES

Formerly Public Heulth Sem”ce publication No. 1000

Programs and Collection J+ocedures. –Reports which describe the general programs of the National

Center for Health Statistics and its offices and divisions, data collection methods used, definitions, and

other material necessary 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 collected data, 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 Reports. –Final reports of major committees concerned with vital and

health statistics, and documen& such as recoin-mended model vital registration laws and revised birth

and death cqtiikates.

Series 10. Data j+om the Health Interview Survey. –Statistics on illness; accidental injuries; disability; use of

hospital, medical, dental, and other services; and other health-related topics, based on data collected in

a continuing national household iriterview survey.

Sm”es 11. Data from the Health 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 det3med prevalence of ipecflc diseases in the United States and

the distributions of the population with respect to physical, physiological, and psychological chracteriztics; and (2) analysis of relationships among the various measurements without reference to an

explicit fhte universe of persons.

Sera”es12. Data j%om 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 care, ambulatory care, hospital care, and family planning services.

Sm”es 14. Data on Health Resources: Manpower and Facilities. –Statisticz on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health occupations, hospitals, nursing homes, and outpatient facilities.

Sen”es20. 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 vital 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 b~ not

available from the vital records, based on sample surveys of those records.

Sert”es22. Data J?om the Nationul Mor&ality 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.

Sers”es23. Dati from the National Survey of Family oGrowth. –Statistics on fertility, family formation and dissolution, family planning, and related maternal and infant health topics derived from a biennial survey of

a nationwide probability sample of ever-married women 1544 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, HRA

Rockville, Md. 20852