disc rupture, or displacement of either the ver-
tebral bodies or transverse processes, This is
not what would be predicted by projection of
the injury patterns observed at 20-30 g’s (which
result in a high incidence of lumbar compres-
sion fractures), as in emergency seat ejection.
In this instance the upper body was evidently
provided considerable support by the arms at
impact. It appears that the arms not only at-
tenuated the force in the body, but supported
the upper body sufficiently to provide rather
good vertebral alignment and prevent the nor-
mal structural trauma to the vertebral column
and pelvis. The lower extremities were not in-
volved, and the well developed muscles of the
shoulder apparently helped since no demon-
strable trauma to the shoulder girdle was
found, although it seems likely some torn liga-
ments may have gone undetected.

A major injury was caused by a sharp rock
at the point of initial impact penetrating both
buttocks with sufficient force to result in two
deep lacerating wounds extending into the
ischiorectal fossa, but without perforation of
the rectal wall. There were superficial and
deep lacerations of the dorsal and volar aspects
of both hands, coupled with a comminuted
fracture at the base of the left second meta-
carpal, a comminuted fracture of the distal
left radius, as well as a compound fracture of
the left radius and severe dislocations of
both elbows, Since more trauma was evi-
dent on the left side, the left arm may have
been slightly more rigid (and probably some-
what behind the center of gravity) upon im-
pact on that side. No trauma of the,shoulder
girdle was found, thus muth of the force ab-
sorbed by the arms may hava been attenuated
before reaching this point.

Among the considerable traumata to internal
organs diagnosed or found; upon autopsy are
the injuries briefly described in Figure A
pneumothorax of both lungs with hematdma of
the left lower lobe, and approximately 60% col-
lapse of the left lung’ occurred. A hematuria
was associated with a clot in the upper major
calyx of the left kidney, located by cystoscopy

énd retro-grade pyelography and confirmed
upon post mortgm. The pelvic membrane was
found hyperemic but with no large laceration.
Several submucosal hemorrhages of the urinary
bladder were noted. The pancreas showed

-l-

some hemorrhage anteriorly with a large
amount of fat necrosis in the surrounding tis-
sue, The spleen received a capsular lacera-
tion, and the liver received a 3-inch laceration
on the posterior aspect of the left lobe.

The pericardium was contused with con-
siderable hemorrhage anteriorly, but without
involvement of the visceral pericardium, There
was considerable ileus of intestinal obstruction
in the abdominal cavity with distention of the
small bowel and edema of the wall, There
was a 2 cm break in the serosa of the anterior
aspect of one of the loops of jejunum, Some
hemorrhage was present in the posterior body
wall adjacent to the spine at the level of the
third to fifth ribs, Although some complaint
of pain in neck movement was noted, no evi-
dence of cervical or skull fracture was found.

Thus, internal trauma from the force of this
deceleration was quite widespread, rupturing
the spleen and liver, with hemorrhages of the
pancreas, mediastinum (pericardium) and left
renal pelvis, and infarcting the bowel (prob-
ably not related to the trauma).

Until more is known about attenuation of
forces within the human body, which is com-
plicated by non-linearity of elastic responses,
plastic deformation, and damping, (not en-
countered in homogeneous structures studied by
the physicist or engineer) it is possible only to
record such traumata in hopes that eventually
enough cases spanning the range of impact ex-
perience can be evaluated to form better an-
alytic and predictive criteria.

It also must be pointed out that this case had
two associated factors which may place it close
to the upper range of human tolerance to im-
pact in the seated position: the subject was a
young athlete in superb physical condition; and,
as*has been shown both in laboratory and
numerous fall cases studied, inhibition of neuro-
muscular Tespqnsgs, as in a state of intoxication,
does appear to provide a high survival theshold
to impact traunia. Previous laboratory impac-
tion of human volunteers in the seated position,
for example, have indicated that a 95 g input at
the level of the buttocks is attenuated to only
10 g at shoulder level, ® as the force travels
through body tissues, fluids, and structures.
This might indicate that in the current instance
2064 g on the buttocks would still result in ap-
proximately 250 g at heart level. Although



or indirect bearing upon the particular case.
While falls from seemingly trivial heights are
all too often fatal, the cases generally selected
for study are those in which the distance of fall
is great and the impacted object is generally
concrete, since these present the best data in
seeking knowledge concerning ‘extreme survival
impact limits. It is contended that such a di-
rect approach is the most realistic means of ob-
taining information concerning impact trauma
and survival conditions and limitations in the
anges above that which human subjects can
be voluntarily subjected in the laboratory. Care-
fully selected cases can often satisfy conditions
nearly as rigid as those in an experimental de-
sign as far as knowledge of environmental
factors is concerned.

Past studies concerned with tolerances to de-
celerative forces utilizing human subjects have
invariably not exceeded the injury threshold
limits, which in the seated position (buttocks
to head) have varied from 33 g (with rate of
onset 50-440 g/sec, at .003-.03 seconds dura-
tion)” to 95 g (rate of onset of 19,000 g/sec.
at .0065 seconds duration)” Studies involving
animals, anthropomorphic dummies, human
cadavers, or theoretical mathematical analog
simulations, while providing valuable estimates,
can not provide valid data directly applicable
to the human in the upper nonreversible
trauma limits, ie, that range between non-
reversible injury and death. Extrapolation
from studies not involving human subjects is
extremely difficult to support and is always
open to some question since conclusions, and
thus prediction, are based upon varidbles
which, although perhaps similar in certam re-
spects, are not identical. ;

The following case demonstrétes the value,
as well as the inherent limitations, of free-fall
studies, While the ¢ombined data of over 1
free-falls are reported separately”, it is felt that
certain cases such as this one should be copsid-
ered as an entity due to the naturé of these
data, and the rather unique circumstances.
The hypothesis that this individual landed in

a geated position, with legs extended and.

slightly elevated, ea with arms downward,
taking most of th€ initial impact on his but-
tocks and transmitting sufficient force through
his hands and arms to proyide support for his
» body is consistent with both the physical evi-

dence (clothes, descriptions) and medical evi-
dence presented later in this report, This case
is thus of particular interest both because of
its obvious direct application to aircraft acci-
dents (in which the vertical component of
force may be much more severe than the hori-
zontal deceleration), and military and space
vehicle application.

DISCUSSION OF THIS CASE

A. Environmental Background. During
the 24 years of its existence, the Golden Gate
Bridge across San Francisco Bay has had a
tragic record of suicides (237 to date) and
accidental falls (at least 85), unmatched by
any other over-water structure in the United
States. Until this incident, late in 1961, only 1
out of over 300 individuals had survived a fall
from this structure. One female still survives,
a male (in 1962) died after 2 hours, and the
subject of the present study survived for ten
days, Since the majority of these falls or leaps
ranged from 200 to 250 feet, the fact that an
impact of such magnitude was survived even
briefly is of considerable scientific interest.

Among the factors which make any Golden
Gate Bridge fall so uniquely treacherous when
water is impacted are a wind of 5-30 knots,
which may tum the body and make mainte-
nance of a vertical attitude virtually impossible,
a trough swell to the waves which may reach a
12-foot crest, and a strong tidal current sweep-
ing toward the sea at about 8 knots, Chances
of survival of leaps from either approach to the
bridge are also diminished by abrupt rocky
cliffs, or, as on the south approach, by a large
concrete abutment (fender) extending some
300 feet along the base of the bridge.

In the early morning (4:30 AM) darkness of
3 December the subject, a twenty-year old
white male in allépetily excellent physical con-
dition vaulted the rail from the east sidewalk of
the Sausalito (north) bridge entrance and
landed 218 feet below on a roadway at the
bottom of a steep’ cliff. He reportedly stated
that he had misjudged the distance, believing
it to be only a twenty-foot drop. The jump
was observed by two California Highway Pa-
trol officers. The subject was allegedly intoxi-
cated at the time.

. a



injury in
paratively
is indicates
organs in
a critical
tolerance

Deceleration”
Butterworth’s

Steady State
luman Body.”

S. Naval Air

ies on. Pelvic
Record 101:

The author gratefully wishes to acknowledge the information and
assistance furnished in this case by the California Highway Patrol, U. S.
Army Corps of Engineers, San Francisco Chronicle, Marin General Hos-
pital, U. S. Coast and Geodetic Survey, San Francisco Coroner's office,
Golden Gate Bridge officials, Mr. John C. Earley, Chief, Dynamics En-
gineering, C.A.R.I., and many others,

' / eat



The railing is four feet above the sidewalk.
Eight feet below, extending outwards for four
feet, is a flat steel support structure called a
chord. The subject, an experienced pole
vaulter, was observed to grasp and vault the
top railing, striking the chord momentarily on
his back. He then rolled off on his left side
and fell unimpeded, landing in a seat-first
position with his legs extended somewhat up-
wards. From the chord to the ground is a
measured distance of 210 feet. At a point 119
feet below the railing a steep cliff extends
some twenty feet out from the vertical, and
this cliff was cleared by the subject’s parabolic
trajectory, The parabolic configuration of this
fall is such that it is believed that the cliff
could have been cleared (for example, in a
similar case occurring from the same structure
three months later, in which the subject lived
for two hours, the point of impact was 26 feet
horizontally from the vertical point of origin).
However, except for superficial tears on the
back of his coat, a minor laceration on his
sealp, and possibly a bruised left arm, no in-
juries or marks which could be attributed to
striking the chord were found. The subject
impacted the ground at the point where the
steep slope meets the shoulder area of a dirt
roadway skirting the bay below. The ground
here is rock covered by gravel, dirt, and rock
debris fallen from the cliff, A mortuary ambu-
lance was summoned and the attendants were
astonished to find the patient conscious and
talking somewhat coherently. Figures 1-4
show views of this bridge jump and impact
area, i y
B. Description of Clothing. Careful exam-
ination of the subject's clothing, coupled with
the nature and location of ihjuries received,
confirms the opinion that the subject impacted
buttocks first. His’ clothes were submitted to
the CARI Physical Anthropology Laborgtory
and placed on an anthropomorphic dumfny of
similar body build, Except for a'T-shirt and
sport shirt which had been washed (although
there was reportedly no blood or dirt on either),
af clothing was untouched. The subject was
ring a new light-colored top coat, pur-
chased earlier th¥t evening. The ground was
slightly damp and there was some vegetation
on the slope; however ng signs of having hit

» the cliff were observed on his clothing, Fig-

-7-

ures 5, 6, and 7 show the location of tears
and marks on front and back of the clothing,
which correspond well with the location of in-
juries. At impact, his highly polished shoes
were still on his feet with only a small amount
of dirt around the edges of the soles. Anter-
iorly, the only damage to his coat was a 3”
puncture-tear of his lower left sleeve with dirt
marks extending for 3” above it. Posteriorly,
there was a vertical 5” tear below the shoulder
on his left sleeve which did not penetrate the
inner layer of the coat. This was the site of a
severe abrasion and moderate skin laceration.
Some 5” below the underarm junction of the
sleeve to the coat there was a triangular tear
extending 4” horizontally and 2%” vertically,
which also did not extend into the inner layer
of the coat. A %” tear below the right scapular
area was also superficial, Another tear was
found behind the left knee, and he received
some knee abrasions. The major physical im-
pact occurred in the seat area, where two dis-
tinct tears corresponded with the very severe
deep wounds received in this area. The front
of the subject’s coat was essentially clean; how-
ever, the back showed dirt abrasions at several
points, which were interrupted in their pat-
terns by creases which indicate that the coat
was probably snugged upwards by the wind
resistance during his fall.
C. Description of Injuries. This individual
received extensive injuries as a direct result of
the impact from the free-fall. Figure 8 sum-
marizes these injuries and combines gross initial
examination (abrasions, lacerations); x-ray, lab-
oratory, and surgical findings; final pathology
and post mortem; and the reports. The internal
traumata and“subsequent secondary complica-
tions may be regarded as the most serious ef-
fects, The patient appeared to be slightly
improved until, at 3:00 A.M. on the morning of
the 10th day, tw suddenly vomited (with a
severe , aspiration which filled the trachea-
bronchial tree with gastric contents) and died.
The remarkable thing about this impact is
that no significant trauma to either the pelvis

‘or the vertebral column could be demonstrated.

Although no lateral x-rays of the lower verte-
bral column were taken, antero-posterior
x-rays of the lumbar and thoracic areas ‘and
antero-posterior and lateral x-rays of the cer-
vical area showed no demonstrable fracture,



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Ficure 2, View from below and to south. Impact point on far side of telephone pole.
4—



Ficure 1. View from point of jump showing railing and chord of bridge.

-3-



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» Ficune 4, Path of fall (photo courtesy San Francisco Chronicle).

. ~6—





Ficure 6. Posterior view of dummy. Arrows point to tears in coat. Bottom of coat is not
torn, indicating coat was up above victim’s buttocks upon impact.

-~9-



|

Ficure 5. Anterior view of dummy dressed in victim's clothing. Note comparative lack of
stains or rips except for area of left wrist.

-—8—



‘epHaq jo proyo Burpnnoid puw pes Jo qed peortoa Suymoys oaoqe wosy MIA “g HUNT



A CASE OF SURVIVAL OF EXTREME VERTICAL IMPACT
IN SEATED POSITION

RICHARD G. SNYDER, Ph.D

ABSTRACT

Physical, biophysical, and medical data are presented conceming the case of a
20-year-old male of excellent physical condition who jumped from the Golden Gate
Bridge in San ‘Francisco, surviving for ten days a free-fall deceleration in the seated
position (buttocks to head) of a calculated 4128 g for .0023 seconds, Specific trauma
resulting from this impact indicates that this may closely approach, the extreme human

survivs

tolerance(s) to impact in this position, and that, while distribution of forces

through Support of the upper torso may greatly minimize injury to the skeletal system,

protection of

,

INTRODUCTION

Our knowledge of human tolerances to de-
celeration forces is mainly limited to the range
of impact in which non-reversible injury oc-
curs, Although it has long been susjected that
man can survive considérably greater forces,
qualitative data int the higher ranges has not
been available. The follofving case, one of a
large number investigated over the past year,
provides some sbasis for extension of fhe ex-
treme limit of human survival in seated
position (buttocks to head force) by pact of
over 25 times the known injury: threshold.

The objective of this paper is to present the
factual data found concerning one human ,ex-
perience in survival of extreme impact forces
and to demonstrate that through such studies
we may learconsiderably more about human
impact tolerances and identify more concisely
the factors affecting injury and survival. Such
* knowledge is necessary to establish parameters

internal organs will present a much more difficult problem.

for design of protective measures to prevent or
modify lethal or injurious levels in aircraft
crashes, as well as other abrupt impact acci-
dents involving very high g forces, Through
such investigations patterns may emerge which
may open entirely new approaches to the pro-
tection of the body during high decelerative
forces.

* The method utilized in this investigation is
study of human subjects who have been in-
volved in acgidental, suicidal, or homicidal (in-
fanticidal) fréé-falls, For the purpose of this
study a free-fall is defined as an unimpeded
drop of a body from a known point to a known
impact point. Among the factors which must
be known are exact height of fall, position of
body at impact, clothing or equipment wom
during fall which might affect the impact, de-
formation and condition of impacted object,
weather, physical condition of the subject, and
any other variable which could have a direct

-1-


such an extrapolation would still be hypotheti-
cal, it does demonstrate that under certain con-
ditions the human body is capable of surviving
extreme impact forces much greater than is
generally recognized.

D. Biophysical Calculations. Due to the
nature of the terrain at this site standard meas-
urement techniques were not useful. A  speci-
ally designed 250 foot weighted wire tape on a
U-control friction reel would not clear the cliff
satisfactorily, and attempts to climb from below
were not successful. Exact distance of this fall
was finally accurately obtained by engineer's
transit, Although the total distance of fall was
218 feet, the subject had traveled some 8 feet
prior to reaching the chord, and to be conserva-
tive in the ensuing calculations it is assumed
that he was at zero velocity at the chord level
and that the total distance of free-fall is 210
feet from the chord to the impact point.

Velocity in free-fall may be calculated as
V’ = 2g, where g (at San Francisco) = 31.15ft./
sec,” , and S=distance. For a free-fall dis-
tance of 210 feet the velocity would be 116.2
ft./sec., neglecting air resistance, Air drag esti-
mates “ indicates a probable velocity at impact
of 103 ft./sec. or 70.54 mph (This fall of 210
feet is thus equal to a’fall of 172 feet in a vacu-
um). The ground at point of impact was a
hard packed alluvial-gravel mixture on bedrock,
and was reported as damp at the time of im-
pact. Examination of the zone of impact indi-
cated negligible deformation of the impacted
surface, Hence nearly all of the deformations
that occurred tluring deceleration of the, body
must have occurred in the body tissu¢s and
structures, i ‘ '

Using the “traditional” methgds for calculat-
ing force in this case, and assuming a very lib-
eral deformation distance of 1 inch, the g force
(g = .034 mph/S) would be $064 g, with rate
of onset (RO = 2g/1) of 2,300,608.7 g/sec/ for
.0023 seconds duration. ry

However, it should be noted that this as-
sumes a constant force during deceleration, and

impact deceleration, particularly of a non-'

hémogeneous body, does not act in this theo-
retical manner. Wissuming the reaction varies
linearly with deformation of the yielding re-
action surface, the deceleration during impact
4 would also vary linearly and the peak accelera-

tion would be twice the value calculated on the
assumption of standard deceleration, or 4128 g.
No depression was noted either immediately
after the fall or upon subsequent inspection at
the site, thus the deceleration distance of the
impacted surface may actually have been con-
siderably less than 1 inch, which also would
have increased the g force by a high factor.
2064 g may thus be considered in fact a very
conservative estimate based upon the available
evidence. While this is over ten-times the
highest g force previously reported “” for human
survival in any position, it is within the survival
envelope of both Von Gierke “ and Hirsch “,
and we have documented cases in our files ex-
ceeding even this force in other positions, Note
that the calculated time is of very short dura-
tion, but is typical of what we are finding in
other ultra-high impact survivals.

Without direct mechanical-electrical meas-
urement of various body tissues at the moment
of impact the specific attenuation for any part
is difficult to state validly. However, lacking
such transducers, we have some evidence of
the magnitude, direction, and distribution of
forces in this case. ‘As noted, the subject
landed on his buttocks, absorbing energy
through his gluteal musculature, and second-
arily, through his arms to his shoulder girdle
and thoracic area.

The dynamic loading, direction, and distribu-
tion of forces in the pelvic area may be calcu-
lated by x-ray views of the fracture patterns
combined with calculated loading. Both ischial
tuberosities probably bore the brunt of the in-
itial impact (weight of 90 Ibs, (145 Ibs, minus
wet. of extremities) x 210 ft.) of 18,900 ft. Ibs.
of energy, which was, however, attenuated con-
siderably by the gluteal musculature, Since
Evan$ and Lissner “ (1955) obtained pelvic
fractures in dynamic loading of intact pelves
subjected to as low, as 20 ft. Ibs. of energy, the
gluteal musculatute, particularly of an athlete,
as in this case, mfst be of great importance in
energy absorption. Medical rotation of the
ischial tuberosities and resulting compressive
strain forces updn the public symphysis was
sufficient to regult in small molecular fractures
about both pubes at the level of the pubic sym-
physis. No separation of the pubic symphysis
was found, indicating shear forces were prob-
ably not as contributory to these fractures. In

. -12—

Subdoral hamarrana withaut elull frantire ——



addition the right ilium received a detached
fracture of the posterior aspect (antero-lateral )
of the iliac crest, possibly caused by medial
rotation of the ala and crest of the ilium in re-
sponse to tensile strain forces. Although it
would seem reasonable that the body weight,
centered upon the sacrum (due to lack of ver-
tebral compression fractures the vertebral
column must have been held fairly vertical at
impact) would act somewhat like a wedge in
forcing apart the ilia, clinical data is negative
concerning this aspect and that of the effects
of tensile strain upon the sacroiliac or iliolim-
bar ligaments.

CONCLUSIONS

Study of instances of human survival of ex-
treme impact forces in which the variables are
known or may be validly calculated can con-
tribute valuable data to the fund of knowledge
concerning human tolerances to such forces.
Cases of accidental falls provide one excellent
means of obtaining such information. While
free-falls resulting in seated impacts (buttocks
to head deceleration) are not common, impacts
in this position ate of importance because of
their direct relationship to vertical force, as
sustained in airplane and helicopter crashes.
It ig not suggested that all individuals could
survive an impact of this nature; however, this
individual, in apparent good physical condition,
did survive the fall itself for an appreciable
time. Since we are searching for the upper
limits of survivability in order to more realis-
tically establish the entire range of hujhan tol-
erances, this case is of particular significance.

This case indicates that: }

(1) The human survival limits for tolerance
to seated (buttocks to, head) abrupt de-
celeration are considerably higher} (at
least 4128 g assumihg linear deférma-
tion, for .0023 secs) than the/ injury
threshold (in the range of 40-220 g).

(2) This case supports previous laboratory
rs experiments showing that tolerance .to
impact force increases with physical con-

dition. Controlled experiments should
be done concerning the actual effect of
neuro-muscular relaxation due to alcohol
or drugs.

(3) Attenuation of force through the gluteal
musculature is considerable and sug-
gests that if proper vertical support for
the upper torso is available to decrease
vertebral loading, seated injury threshold
level might be increased.

(4) The time duration of deceleration ap-
pears to be a critical factor, and reducing
it (for example to .002 secs or less), as-
suming other factors constant, may also
help to increase human tolerance levels.

(5) Extreme impacts in the buttocks-to-head
attitude can result in severe injury in
internal organs with comparatively
minor skeletal trauma. This indicates
that protection of internal organs in
longitudinal impacts will be a critical
problem in increasing human tolerance
levels.

REFERENCES

1. Stapp, J. P. “Tolerance to Abrupt Deceleration”

Collected Pa; on Aviation Medicine. Butterworth’s
Scientific Publications, London, 122-139, 1955.

2, Swearingen, J. J., E. B. McFadden, J. D. Garner, and

J. G. Blethrow “Human Voluntary Tolerance to Ver-
tical’ Impact” Aerospace Medicine 31(12):989-998,
1960.

3. Snyder, R. G. Human Survival of Extreme Vertical

Impact (In preparation), 1962,

4. Early, J. Unpublished chart “Body Terminal Velocity,”
1962.

5. DeHaven, H. “Mechanical Analysis of Survival in

sFals from Heights of Fifty to One Hundred and Fifty
Feet” War Medicine 2: 586-596, 1942.

6. Von Gierke, H. “On the Relation Between Steady State

Response and dyapact Response of the Human Body.”
Symposium on Biomechanics of Body Restraint and
Head Protection, June 14-15, 1961. U. S. Naval Air
Materiel Center, Philadelphia.

7. Hirsch, A. C. ‘personal communication.
8, Evans, F. G.,and H. R, Lissner “Studies on. Pelvic

Deformation$ and Fractures” Anatomical Recotd 101:
225-241, 1955.



A CASE OF SURVIVAL OF EXTREME VERTICAL
IMPACT IN SEATED POSITION

RICHARD G. SNYDER, Ph.D

Chief, Physical Anthropology Section
Protection and Survival Branch

62-19

FEDERAL AVIATION AGENCY
AVIATION MEDICAL SERVICE:
AEROMEDICAL RESEARCH DIVISION
CIVIL AEROMEDICAL RESEARCH INSTITUTE
OKLAHOMA CITY, OKLAHOMA
OCTOBER 1962


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Frcure 7. Main point of impact on buttocks. This resulted in two severe penetrating wounds.

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