subject of intensive research. “Tertiary collision
injury” may be defined as the trauma resulting
from the interaction of the occupant and his re-
straint system. That such phenomena occur
must not, however, serve as argument against the
utilization of restraint systems, since these latter
give significant needed protection from extreme
impact. Rather, these phenomena must be viewed
as analogous to the untoward side effects of an
otherwise life-saving drug—effects which may be
eliminated through further research.

These experiments also provide cogent and
quantifiable argument for considering the effects
of variation in occupant position in determining
the lethality of a given “dose” of deceleration.
In general, it may be stated that for the baboon
restrained by lap belt alone, rearward-facing im-
pacts are in terms of sustained g.-forces, about
three times as tolerable (40-45g. survivable) as
side-facing impacts (15-20g. survivable). For-
ward-facing impact orientations result in injuries
intermediate in degree (25-35g. survivable).
While the quantitative extrapolation of these
findings into deceleration parameters (peak,
onset rate, and duration of g.-forces) for the
human situation may not be simple, the struc-
tural homologies of the baboon and human pro-
vide much conviction that there is a distinct
correlation between them for the effects of posi-
tion at impact. In other words, in humans, as in
baboons, a given “dose” of impact appears to be
most tolerable in the rearward-facing position
and least tolerable in the sideward-facing posi-
tion. From a practical standpoint, this finding
would argue against the utilization of side-facing
seats for airline stewardess jump seats where
incapacitation of a stewardess may disastrously
affect. the controlled and orderly evacuation of
an entire plane load of passengers.

These tests demonstrate that abrupt decelera-
tion may have potentially grave effects that may
not necessarily be correlated with the degree of
tissue disruption or with the magnitude of im-
pact forces. For example, fetal death occurred
in all pregnant animals impacted although (a)
irreversible anatomical trauma to the mother or
fetus could not be demonstrated, and (b) posi-
tion at impact, a very significant variable in
determining the survivability of adult animals,
had no apparent influence on results for the fetus
since rearward- as well as forward-facing im-
pacts resulted in fetal demise. A second example

18

demonstrating the lack of correlation between
overt trauma and injury potential is the effect
of impact on the pancreas. In this organ, al-
though the actual degree of tissue disruption was
slight, its consequences (acute sterile pancreati-
tis) would have been extremely serious.

Another finding is the occurrence of myo-
fibrillar degeneration. This finding, described
by others‘ as an agonal change of the myo-
cardium associated with sudden death, has been
dismissed as artifactual by some pathologists.
Others have, while cautious, allowed that it might
represent a subtle but genuine histopathological
change of obscure mechanism. If the latter in-
terpretation is correct, the changes observed
definitely represent pin-point areas of perhaps
irreversible myocardial degeneration, and it
would be interesting to know what effects such
lesions may have on myocardial function months
or even years after impact. Similarly, in the
kidney the minute areas of interstitial hemor-
rhage, while not lethal, might ultimately pro-
foundly affect the function of that organ.*?

In these tests, the trauma potential of several
restraint systems was examined and composed.
The single diagonal chest restraint resulted in
immediate fatal injuries at the g.-levels tested.
Simple lap-belt restraints were more effective in
preventing injury than the single diagonal belt,
but also resulted in serious and fatal injuries at
higher g.-forces. The small sample precludes
dogmatism, but the available evidence indicates
that “loose-high” lap belts contribute to injury
severity greater than those snugly fitted and
worn low over the abdomen. Lap belts and
shoulder harness combinations (American 3-
point or double shoulder) resulted in less injury
in this series of tests than did any of the com-
monly used restraint systems. The two experi-
mental devices, Y-yoke with inertia reel and,
especially, the air-bag restraint system, gave
maximum protection to the occupant against
tertiary collision injury.

Finally, tests such as these demonstrate that
adequate evaluation of any restraint system must
include experiments with living animals. Tests
on anthropomorphic dummies, cadavers, and hu-
man volunteers can all contribute significantly
to the development of restraint devices, but the
final test of their effectiveness lies in, and can
only be determined by, the response of the living
system to an impact profile with parameters
simulating as closely as possible those of actual
accident environments.


and trauma to the kidney (Fig. 6), liver (Fig. 7),
spleen, pericardium, lungs, pancreas (Fig. 8),
adrenals, rupture or hemorrhage of the sigmoid
colon, and dural hemorrhage. Diagonal linear
contusions from belt impingement were marked.
Among other findings, it is interesting to note
that myofibrillar degeneration was observed in
two of the animals during microscopic examina-
tion of myocardial tissue (Figs. 9,10). A similar
observation was noted in one 22g. side-facing,
3-point belt impact, one 49g. forward, yoke-
restraint impact, and to date, in four animals
subjected to vertical drops in a current series by
Snow.** Fragmentation of the myocardial fibres
and whether it represents decelerative, traumatic
rupture of the heart as described by Moritz and
Atkins,°° a processing artifact, or whether the
heart is in systole or diastole at the time of im-
pact, has been discussed by Mason.*® It should
be noted that an experimental study of chest
impact recently completed by Life and Pince‘*
has conclusively demonstrated that severity of
cardiac trauma in canine impact is directly re-

lated to the cardiac cycle and contractile state
of the myocardium at the time of impact.

The degenerative changes observed in our study
in cardiac muscle of baboons subjected to high-g.
forces consist of random areas in which there is
disruption of the myofibres by transverse sepa-
ration and apparent rupture of the sarcolemma
permitting separation of the fibrils. Nuclear
changes are marked, some nuclei are swollen and
ballooned, some are ghostly and indistinct, and
some are shrunken, irregular in shape with con-
densed chromatin and surrounded by a clear zone,
while others are frankly pyknotic. Lysis of
nuclei appears to have occurred in the more se-
verely affected areas. Vacuoles are present in
many fibres and nuclei are eccentric in position.
The theory that these are artifacts caused by a
dull microtome knife is unconvincing because
random areas of fragmentation usually adjoin
relatively normal ones. The overall impression
is that the changes described are the result of the
tissues being subjected to extreme stress. A final
interpretation will require further study.

Fiaure 8. Pericapsular hemorrhage of kidney occurring in single diagonal belt tests.

12


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the harness attached separately at each side ad-
jacent to the lap belt tie-downs, and was also
equipped with strain gauges (Fig. 1-E). The
yoke of the harness was formed at the posterior
aspect of the head, but did not touch the head
or neck. It provided some rearward motion pro-
tection, but we did not test to what degree it
could offer protection from hyper-extension in
rear impacts. The harness, continuing as a
single belt from the yoke, was attached overhead
at a 45° shoulder angle (relative to the hori-
zontal plane) into the inertia reel, which was
activated at 0.3g. For the inverted-Y yoke sys-
tem tests protocol was established for one run
at 30g. (sled X, avg. g.) in both forward-facing
and side-facing positions, one run at 43g., and
one run at 49g. An initial value of 30g. was
selected because this was the level at which lethal

impact injury occurred in about 50% of the ani-
mals when impacted with lap belt only restraint
systems. Sled g. was chosen as a measure since
this could be accurately determined and com-
pared to previous tests. Subject decelerations
had proven to be extremely unreliable in previous
tests due to problems of orientation and mounting
procedures.

The seat was padded with 1-inch Ensolite on
the back and seat. No physiological measures
were made in 50 tests to reduce chances of surgi-
cal artifacts. In another 12 tests, involving
pregnant animals, physiological monitoring con-
sisted of the following: intra-abdominal pressure
was measured in the peritoneal cavity with a
Micro-systems 1017 pressure transducer im-
planted in the wall of the uterus or by an intra-
amniotic Statham 222 pressure transducer.

SIX RESTRAINT SYSTEMS TESTED

B. DIAGONAL BELT

Fieure 1.

- D. LAP BELT WITH DOUBLE
"SHOULDER HARNESS _

3

F. AIR BAG RESTRAINT

The six types of restraint systems tested.


APPENDIX A

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21


The patterns were as close to aircraft or auto-
mobile crash decelerations as the Daisy Decelera-
tor could be programmed. Paired tests were run,
with one animal at each level allowed to survive
to permit study of post-impact chronic effects.
One animal was run twice at 46 peak g. with no
observable trauma and then was run a third time
at 50g., after which autopsy revealed a ruptured
bladder and dural congestion.

At 33g., the animal terminated and autopsied
immediately post-impact revealed only slight
dural congestion. A second animal, impacted at
36g. and allowed to survive for 90 days, was
found to have no trauma.

At 47g., injuries to the terminated animal were
dural congestion and lung, adrenal, and pan-
creatic hemorrhage. The paired animal, also run
at 47g., but allowed to survive 30 days, showed

Ficure 12. Baboon prior to impact run utilizing Air Bag Restraint System. Air bag is stored in panel 10 inches
forward of animal and will be inflated at impact. The restraint holding arms will be released 0.6 sec. prior to

impact.


due to lap belt impingement were found to occur
at 10g. (300 g./sec., 0.002 sec.). In one 26g. im-
pact (the highest lap-belt-only experimental test
run on humans), the subject complained of severe
epigastric pain persisting for 30 seconds and
thoracic pain for 48 hours. Seat belt forces of
4,290 pounds, and an average impingement force
of 89.3 psi over the belt area were calculated. *#%***
Subsequent tests on the Daisy track have not
exceeded 15g., until recent tests of 17g. by the
National Bureau of Standards,’ considered to be
the upper limit of subjective tolerable impact
with a lap belt system in forward impact.

Forward, as well as rearward, lap-belt-only
impact for pregnant baboons at 20g. resulted in
fetal demise, even when the mother was not sig-
nificantly injured. Death to the fetus occurred
in association with placental separation, trau-
matic head injury, and maternal shock.’®

Figure 4,

Fourteen tests with lap-belt-restrained subjects
impacted in the 90° sideward facing body posi-
tion (Fig. 3) resulted in injuries surprising in
their extent (Table I-B). In this series, sled
entrance velocities ranged from 36.4 to 75 ft./sec.,
15 to 8lg., and 1,200 to 3,100 g./sec. onset rates.
Since all animals were terminated post-impact,
survival must be judged from the trauma found
upon autopsy, and it seems probable that without
immediate and extensive medical assistance only
the 15g. impact would have been survived. It is
interesting to note that human voluntary lateral
subjective tolerance levels have been found to be
about 9g. (Zaborowski),** much lower than for
either forward- or rearward-facing positions.
Five animals received ruptured bladders (which
did not occur in forward or rearward lap belt
impacts). Contusions, tears or lacerations, and
one complete severance of the uterus also occurred
in five cases. In three instances, cervical frac-

emia sears

Subdural hemorrhage in baboon impacted forward facing, lap belt only, at 82g, and 75 ft./sec. velocity.

A high frequency of dural congestion and hemorrhage was found.

8



36.

37.

38.

39,

40.
41.

42,

43.

44,

45,

46.

*
A

48.

49.

50.

52.

53.

. Nick, W, V.

Literature and Report of a Case. New York State

J. of Med, 48: 903-906, 1948.

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CB: Fulerum Fractures of the Lumbar Spine.
JAMA 193: 240-241, 1965.
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TN-57-1. Holloman AFB, New Mexico. 1957.

} Srapp, J. P., et al: Human Tolerance to Aircraft

Seat Belt Restraint. J. Aviat. Med. 29: 187-196,
1958.

Effects of Seat Belts: Man.
Environmental Biology, p. 229. Federation of Amer-
ican Societies for Experimental Biology. Bethesda,

1966.

. Srern, E. L.: Traumatic Injuries to the Pancreas.

Amer. J. Surg. n.s, VIIT : 58-74, 1930.

R. F., Rue, L. W.,
Epwanps, R. H:, and Carter, V. L.: The Effects of
Severe Impact on Bears. Presented, 34th Annual
Meeting Aerospace Medical Association, Los Angeles,
29 April-2 May, 1963.

. Teare, D.: Post-mortem Examination on Air Crash

Victims. Brit. Med. J. 2: 707-708, 1951.

. THAL, A. P. and Witson, R. F.: A Pattern of Severe

Blunt Trauma to the Region of the Pancreas.
Gynecol. & Obstetrics 119: 773-778, 1964.



posterior and lateral view radiographic studies
were made prior to autopsy. Gross and micro-
scopic tissue study of the brain was complemented
by electronmicroscopy examination for fibrin-
olytic activity. Blood analyses were conducted
in a search for biochemical indicators of impact
stress and/or tissue damage. Blood samples for
these analyses were taken for the seven air-bag
subjects prior to impact, immediately post-
impact, and for the three animals observed for
1-8 months post-impact, at 7-day intervals for
one month. The hematology is summarized in
Snyder, et al.°t Specific techniques employed
are those provided in detail by Life.**

II. Results and Discussion

In each restraint system tested in this series,
injuries to occupants were found which could be
attributed to the system itself. The patterns of
trauma were found to differ in each case as a
function of the type of restraint and the body
kinematic action during impact. Additional
variables found to be of importance included
magnitude, onset rate, velocity, and time dura-
tion of impact, distribution of force upon the
body, and direction of force (body orientation
to the impact). Variables not studied, but also
believed to be of importance would include the
age, sex, and physical condition of the restrained
subject.

This series of tests provide a basis for the
assessment of traumatic and protective qualities
of these restraint systems for the baboon sub-
ject. The confidence with which results observed
on the baboon may be extrapolated to the human
is reinforced by the fact that the injuries found
in these tests are similar to those which have been
reported for human subjects in accidents involv-
ing similar restraint systems. Such an experi-
mental approach testing living systems is a
necessary corollary to studies based on the use
of cadavers or anthropomorphic dummies.

Tables I-VI (Appendix A) provide the results
of gross and microscopic pathology and note the
individual conditions for each test, a summary
of the physical data, and records of peak belt
forces. Our findings for each system will be
briefly discussed here, but for further detail refer
to these tables.

A. Lap Belt Only. Lap belt refers to a single
belt worn across the anterior aspect of the pelvic
structure (Fig. 1-A). Properly worn, this re-

strains the body by its strongest structural ele-
ments and reasonably close to the total body
center of gravity. It prevents ejection, which
has been demonstrated to be the major single
cause of fatal injury in automotive type acci-
dents ;*7 however, in forward or lateral impact
it offers no upper body support, thus head and
thorax are free to “jackknife” over the lap belt.

The lap belt restraint is the most commonly
used system for both aircraft and automotive
occupants. Its effectiveness has been well docu-
mented by many investigators, their studies in-
dicating ‘that the lap belt alone can reduce
injuries by substantial amounts.%77  Huelke
and Gikas found in their study of fatal accidents
that “of 48 ejectees, 38, or 80 percent, would have
survived if they had been wearing only the lap
seat belt.”*’ Nevertheless, as Fish & Wright
have recently noted, this device can in itself be
responsible for distinctive injury patterns. In-
jury to the jejunum,'***7? spleen,!* pancreas,"
duodenum,” ileum,? and abdominal hernia‘*® has
been attributed directly to the lap belt. In addi-
tion, lumbar compression fractures have been re-
ported since the body hyper-extends over the
belt,282.5461 as well as transverse fracture of the
vertebral body’ attributed to the high placement
of the lap belt which allowed the belt to act as a
fulcrum, literally “splitting apart” the vertebral
body. A “splitting fracture” of the pedicles,
transverse processes, and lamina of the third
lumbar vertebra has been reported.”* Smith and
Kaufer have recently reported finding 10 of 17
cases of spine injuries from seat belts, involving
a tension-type fracture to the lumbar vertebrae.°*
In pregnant women traumatic rupture of the
uterus, 45 ventral hernia,** and placental sepa-
ration** have been reported.

Teare’s findings of abdominal and thoracic
aortic ruptures, attributed to the jackknifing of
occupants over the lap belt during a 1951 Comet
jet airliner crash in England,® the report of
DuBois of 23 cases of intra-abdominal trauma
and 32 cases of contusions in 858 aircraft acci-
dents in 1952,° and that of DeHaven, e¢ a/*® in
which they attributed only bruises due to the
belt to 1,029 survivors of 670 light aircraft acci-
dents, were early efforts at investigating this
problem. Lap belts are being worn more by
larger numbers of individuals as airline travel
becomes more common, and because all new auto-
mobiles manufactured in the U.S. are required


Maternal blood pressures were recorded pre-
and post-impact by sphygmomanometer or
through a trans-femoral catheter in the abdomi-
nal aorta, connected to a Statham P-23 pressure
transducer. Maternal electrocardiograms were
obtained with Beckman silver-silver chloride ad-
hesive electrodes. Fetal electrocardiograph leads
of insulated stainless steel wires were inserted
into the scalp and arm of the fetus. Fetal heart
rates were monitored by stethoscope and/or re-
corded continuously by  electrocardiography.
Serum electrolyte determinations and arterial
CO, for 13 pregnant animals were determined.
For details of blood chemistry technique for each
case the reader is referred to Crosby.1®

Each subject was anesthetized with 1 mg./1 kg.
body weight Sernalyn ‘®) prior to each run. I-V
Nembutal “® was used on one animal and In-
novar-vet®) on two animals. Ether, atropine,
and diphenylhydantoin were also used prior to
surgery in the pregnant series. These drugs did
not appear to significantly alter physiologic re-
sponses to impact.

The subject was then removed from the cage
after the drug had taken effect and prepared for
the test in the adjacent surgical room. Hands
and feet were covered with tape and the animals
muzzled in order to facilitate handling. In the
lateral tests, 1-inch targets were positioned along
the head and trunk for later photometric analysis
of body kinematics. The animals were next taken
to the test sled, positioned, and the seat belt ten-
sion adjusted. Low-strength masking tape was
used to keep the legs and thorax in proper posi-
tion for the run; however, this easily tore upon
impact and did not provide additional restraint.
In the air-bag tests a loop of rope under the
arms and attached over the seat back supported
the animal in an upright position until mechan-
ically released by cable 0.6 second prior to impact.
Muscle tonus was carefully monitored to assure
that all runs were made at the same level of
anesthesia.

The strain gauges were fabricated for the
6571st Aeromedical Research Laboratory by
Land-Air Division of Dynalectron at Holloman
AFB. They were originally designed for the
standard 2-inch wide belt, but were modified to
the 1-inch webbing used in these tests. Gauges
were placed at each end of the belt; two were
used for lap belts and four gauges for the other

systems. Each strain gauge buckle was instru-
mented with four strain gauges to measure the
bending moment due to the force imposed on the
belt. Although each buckle contained eight ele-
ments, it electrically appeared as a four-active-
arm bridge. When the belt was stretched, the
metal of the buckle was stressed and deflected.
Resistance of the electrical elements changed as
a result of changes of strain on the metal. Cali-
brations were made by placing a known force
on the belt and measuring the electrical output.
of the bridge.

Photographic coverage included use of a Wad-
del 16-1A 2,000 fps camera for frontal view,
and one or two Ippolito Fastex 2,000 fps cameras
for lateral views. In some runs, film from one
of the lateral views was processed immediately
and wet-viewed to examine results of each test
quickly prior to the succeeding tests; 16 mm.
documentary color film, 35 mm. still color film,
and 4x5 still photography were also obtained.
In addition, pre-impact, during impact, and post-
impact black and white Polaroid ® photos were
obtained. These served as useful references to
cross check specific position, run numbers, and
other details of notes.

In 12 runs, the pregnant animals were clini-
cally monitored for periods from 20 minutes to
4 hours. In the seven animals impacted with air-
bag restraints a post-impact blood sample was
drawn prior to termination (5-20 minutes post-
impact), and in all the others the animal was
terminated within 5 minutes post-impact.

Gross autopsy was conducted at the 6571st
Aeromedical Research Laboratory immediately
post-impact for the terminated subjects, or the
animals were packed in ice and immediately
transported by air to the autopsy facilities of
CAMI in Oklahoma City, where autopsy was
completed within 24 hours. Three animals were
not immediately terminated, two being allowed
to survive for 4 weeks, and one for 12 weeks,
post-impact to determine chronic impaet effects.
In these cases, the animals.were observed and
autopsied at facilities of the Space/Defense Cor-
poration, Birmingham, Michigan.

In the lateral series two Field Emission high-
speed roentgenograms were taken of each run,
the first shot being triggered at impact and the
second at about 0.65 second after initial sled
entry into the brake; however, none of these
proved useful. Whole body post-impact anterior-


no gross trauma, and slight emphysema upon
microscopic examination.

The final series at 55g., resulted in dural con-
gestion, uterine broad ligament hemorrhage, and
lung and liver congestion in the terminal animal,
all considered minimal. The paired animal run
at 57g. and allowed to survive 30 days prior to
autopsy, was found to have no gross trauma.
Microscopic trauma involved pulmonary edema,
vesicular emphysema, and periadrenal hemor-
rhage. Blood biochemistry studies pre-impact,
post-impact, and at 7-day intervals for 1 month
on the surviving control animals did not indicate
stress changes which can be meaningfully inter-
preted at this time. It is interesting to note that
dural congestion, evident in each animal sacri-
ficed immediately post-impact, was not found in
the 30-day or 90-day post-impact controls. This

may indicate that such injuries are transient in
nature. There seems little doubt, on a relative
and comparative basis, that the air-bag restraint
system is reaching a stage in development where
it may have practical application.

The baboon’s impact tolerance limits with this
system appear to be much greater than the 57g.
tested.

IV. Conclusions

The tests reported in this study demonstrate
that while restraint systems may protect the oc-
cupant from the very serious trauma that may
be caused by ejection or “secondary collision,”
they may in themselves act as sources of generally
less lethal but yet significant injury. Such find-
ings indicate that still a third-order of collision
phenomena (“tertiary collision”) should be the

Figure 13. Inflation of the Air-Bag Restraint at moment of impact.

Va


Frievure 3. Baboon positioned in seat on omni-directional sled prior to impact run in lateral body position. Note
photometric locators on animal and along portion of seat back.

7


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AM 69-3

PATHOLOGY OF TRAUMA ATTRIBUTED TO RESTRAINT
SYSTEMS IN CRASH IMPACTS

Richard G. Snyder, Ph.D.
Clyde C. Snow, Ph.D.
Joseph W. Young, A.M.
Warren M. Crosby, M.D.
Col. G. Townley Price, USA (Ret.) D.V.M.

Approved by Released by
Kit Bite (USége€ mb
J. Roserr Dixiz, M.D. P. V. Srecer, M.D.
Curr, Civ ArromepicaL Feprra, Arr Surceon
InstitoTe

February 1969

Department of Transportation

FEDERAL AVIATION ADMINISTRATION
Office of Aviation Medicine


animals, they were considered to be a direct result
of the trauma.

The significance of the inter-acinar hemor-
rhages observed in the pancreas at necropsy
following impact is unexpected and has been
carefully considered. Previous descriptions of
pancreatic injury have been related to dietary
excesses, direct trauma resulting from blows over
the left upper quadrant of the abdomen, surgical
trauma, and reflux from the intestine,”*
9941,51,66,69,74,75,78,81 byt we have not found similar
reports of pancreatic injury related to sudden,
violent compression and/or displacement of the
viscera such as we found in this series of experi-
ments. Immediately after impact, we observed
retroperitoneal and intralobular hemorrhage
grossly and inter-acinar hemorrhage histologic-
ally. It is clear that there have been intra-
abdominal forces sufficient to rupture the capil-
lary bed. It is not unreasonable to believe that
these same forces could break the more delicate

radicles of the intralobular ducts which are
formed only by the centroacinous cells with the
release and activation of pancreatic enzymes.
However, this must still remain speculation until
proven or disproven by clinical study of sur-
vivors.

Recent work suggests that the pancreatic
hemorrhage may be more critical in the baboon
than in man since recent studies’ indicate that
the output of serum amylase and lipase is several
fold higher in the baboon than in the human.
Hence, mechanical disruption of the duct system
with consequent release of enzyme might be ex-
pected to result in a far more fulminating out-
come in baboons than in humans.

Rearward-facing body orientations (Table
I-C) at impact were used in four cases, all at
20° pitch attitude. These ranged from 22 to
44g., 59 to 88 ft./sec. velocity, 2,300 to 5,850
g./sec. onset rates, and 76 to 100 milliseconds
time duration. Seat belt forces of 30-120 pounds

Fiaure 6. Subperitoneal hemorrhage in pancreas resulting from subject's impingement upon single diagonal belt
only.

10


tures occurred with complete atlanto-occipital
separation. Transection of the spinal cord oc-
curred in one 30g. impact. Again, such cervical
trauma did not occur in either forward or rear-
ward lap belt tests. The most significant finding
was that of pancreatic hemorrhage in all lateral
cases which were autopsied. Intra-cranial hemor-
rhage was again noted in each case (Fig. 4).
Inter-acinar hemorrhage, typical of these lateral
impacts, is shown in Figure 5. Although such
trauma has not been reported by previous inves-
tigators, even in tests with humans exposed to
22g. and a bear to 46g.,° such tests have been
conducted with full body restraint and not lap
belt alone, as in these tests.

To clarify the role of post-mortem pancreatic
degeneration, one baboon was terminated without

Figure 5,

being impacted, and treated in the same manner
as those in the impact series. After termination
with Nembutal ), the cadaver was held at room
temperature for 1.5 hours and then packed in
ice in a shipping container. A temperature probe
was inserted inferior to the right lobe of the liver
and recordings kept. Body temperature of
96.8°F. dropped to 96.2°F. after 1.5 hours, to
64,8°F, within 14 hours, and to 48°F. within 24
hours. After 24 hours, gross necropsy and histo-
pathologic examination revealed mild pancreatic
necrosis without pancreatic hemorrhage. This
indicated that part of the necrosis observed dur-
ing necropsy was due to post-mortem changes
in the pancreas, but since associated hemorrhagic
findings occurred only in pancreases of impacted

Inter-acinar hemorrhage of pancreas typical of lateral baboon impacts at every level tested at and

above 16.5g.

9




70. Toutns, S.

H.: An Unusual Injury Due to the Seat
Belt. J. Trauma 4: 397-399, 1964.

71. Tourry, B. and Garrett, J.: Safety Belt Effective-
ness in Rural California Automotive Accidents.
Automotive Crash Injury Research of Cornell University,
1960.
Turnsow, J. W., Rornr, V. E., Bruectnk, G. M.,
and Roxener, H, F.: Crash Injury Evaluation.
Military Troop Seat Design Criteria. U.S. Army
Transportation Research Command, Fort Eustis, Va.
TREC-TR-62-19. November 1962.

72.

73. VON Banr, and Eriksson, E.: Injuries Caused
by Safety Belts. Svensk. Lakurtidin. 58: 141-143,
1961.

74, Warren, K. W.: Management of Pancreatic Injuries.

The Surgical Clinics of North America 789-802.
Philadelphia and London: W. B. Saunders Co. 1951.

. WeITzMAN, J. J. and Swenson, O.: Traumatic Rup-
ture of the Pancreas in a Toddler. Surgery 5
309-312, 1965.

76, Wittrams, R, D, and Sarcent, F, T.: The Mechanism
of Intestinal Injury in Trauma. J. Trauma 8:
288-294, 1963.

29

a
I

. WILSON,

. WittiaMs, J. S., Lies, B. A., and Hare, H. W.: Intra-

Abdominal Injury from Seat Belts.
303-315, 1966.

R. F., Tacerr, J. P., Pucerrk, J. P., and
Pancreatic Trauma. J. Trauma 7:

J. Trauma 6:

Watr, A
643-658, 1967.

. Worr, R, A.: The Discovery and Control of Ejection

in Automobile Accidents. JAMA 180: 114, 1962.

80. WoopHtLr, R. B.: Traumatic Rupture of Pregnant
Uterus Resulting from Automobile Accident. Surg-
ery 12; 615-620, 1942.

81. Wricht, L. T., Prreor, A., and Hix, L. M.: Trau-
matic Subcutaneous Injuries to the Pancreas. Amer.
J. Surg, 0.8, 80: 170-175, 1950.

82. Youns, 1966 Recommendations for Restraint
Installation in General Aviation Aireraft. OAM
Report 66-33, Federal Aviation Agency, 1966.

83. Youne, J. W.: A Functional Comparison of Basic
Restraint Systems, OAM Report 67-13, Federal
Aviation Agency, 1967,

84. ZaBorowski, A. V., RotustTern, J. D., and Brown,

W. K.: Investigations in Human Tolerance to Lateral
Impact. Pr nted, 36th Annual Meeting Aerospace
Medical Association, 26-29 April, New York City.
Abstract: Aerospace Med. 36: 168-169, 1965.



to have belts installed. Thus, it should not be
surprising to note that there has recently been
a sharp increase in the incidence of trauma at-
tributed to the seat belt, reflected in the more
than 20 clinical reports in the literature con-
cerned with this problem since 1961.°7

Forward-facing lap belt impacts were con-
ducted in 18 of the 36 lap belt tests (Table I-A).
Of these, five were impacted with seat pitch atti-
tude of 45° to simulate a jet airliner crash, while
two were at 13° and 11 at 20° to simulate seating
profile in a level aircraft or automotive accident.
Entrance velocities ranged from 38.2 to 87 ft./sec.,
onset rates from 1,400 to 6,800 g./sec., time dura-
tions from 0.050 to 0.080 second, and magnitude
from 16.5 to 40g.

In all cases, transverse linear contusions of the
anterior abdominal wall corresponded to the po-
sition of the belt at impact (Fig. 2). It is sug-
gested that a careful examination for such
bruising be routinely made in human accident
victims as it may serve as a valuable sign of
more serious intra-abdominal injury. Up to

approximately 25g., congestion and/or minimal

Figure 2.

6

a

hemorrhages were noted in the brain, spleen,
heart, uterus, and pancreas. In general, however,
the pathology appeared to be reversible and com-
patible with recovery. Above 25g., injury was
more severe and along with damage to the pre-
viously mentioned organs, ruptured urinary blad-
ders, pulmonary lacerations and interstitial and
pericapsular renal hemorrhages were increasingly
frequent. Beyond 30g. survival could be consid-
ered marginal and beyond 40g., the impacts were
definitely lethal.

Since previous clinical reports have suggested
that incorrect wearing (loose, high) of the lap
belt may have contributed to the injuries,’#2%353
556177 an attempt was made to duplicate this
factor in three runs. While this did appear to
result in more extensive injury in one case at
30g. (8372), it was inconclusive for two other
tests at 34g. (3315) and 40g. (2880).

Previous human tests by Lewis and Stapp with
healthy, young male subjects resulted in com-
plaints of abdominal pain at 15-20g.4 Minimal
contusions over the hip area and abdomen as well
as strain of the anterior abdominal musculature

Typical contusion resulting from impingement of lap belt in impact.


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and included patterns simulating exposures in
forward- and rear-facing seats in aircraft as well
as automotive impacts.°** The preliminary
work in which 11 pregnant baboons were sub-
jected to 12 experimental impacts, indicated that
at 20g. maternal trauma was minimal, but fetal
death occurred in association with fetal head
injury, placental separation, and maternal shock.?*
In response to requests by the Society of Auto-
motive Engineers S-9 Committee and the Stew-
ard and Stewardess Division of the Air Line
Pilots Association, a second test series examined
the problem of lap belt only restraint protection
for aircraft occupants in lateral seating positions
such as lounge, aircrew, or stewardess station.
Twenty-four deceleration tests were performed
on 24 adult female baboons, in controlled experi-
ments comparing sideward, rearward, and for-
ward impact effects. Impact levels causing
injury to the baboon subjects in 14 lateral orien-
tations were determined to be much lower than
in either rearward- or forward-facing body
orientations, with fatal injuries occurring as low
as 16.5g. when the occupant wore a lap belt only.
A final test series compared two types of ex-
perimental systems, the inverted-Y yoke with
inertia reel and the airbag restraint system.
In addition, forward, rearward, and sideward
tests were made of other systems currently in
use, such as the 3-point (lap belt-diagonal belt
system) and the diagonal only restraint system
favored in some European automotive vehicles.
The entire series of related studies of restraint
protection and impact injuries using baboon sub-
jects has been brought together in this paper to
present, an overall view of trauma sustained by
the occupant restrained by the systems evaluated.

II. Methods and Materials

Sixty-two deceleration tests were performed on
59 adult female Savannah baboons (Papio cyno-
cephalus )*, ranging in body weight from 15.5 to
36 pounds (9.5 to 16.3 kg.). Age estimates based
on dental examination ranged from 414 to 12
years (CS).

The tests of this series were conducted on the
Daisy Decelerator between 23 May 1966, and
3 June 1967.7 Several sled and seat combina-
tions were used, depending upon the particular
profile run. All seats were scaled down propor-

*Previously designated by primatologists as Kenya Baboon
(Papio doguera).

a sl

tionately for the baboon, and as noted in Table I,
the F-111 test frame, mounted on the ARL Omni-
Directional sled was used for most of the tests.
The 4,500-pound tensile test. nylon webbing used
in each test was replaced after each run; lap
belt angle was 55° to the plane of the seat pan.
Prior to each run, static belt tension for each
side was stabilized at 1.5 kg. (3.3 lb.).

Subject orientations (presented in Table I)
were 90° sideward facing (45° seat pitch), 50°
sideward facing (138° and 20° seat pitch), for-
ward facing (13°, 20°, and 45° seat pitch), and
rearward facing (13° and 20° seat pitch) body
orientations.

Time duration varied from 0.059—0.121 second,
the latter being the longest duration at 30g. the
Daisy track was capable of providing safely with
this sled load. Entrance velocities varied from
36.4 ft./sec. to 94.4 ft./sec., rate of onset from
1,200 to 6,800 g./sec., and peak sled forces from
15g. to 57g. Figure 1 diagrams the configuration
of the various restraint systems used. Since the
air-bag and inverted-Y yoke systems were ex-
perimental, a brief additional description for
these follows: The air-bag restraint for the
baboons was scaled down to be of the same rela-
tive size as the full-size version for the humans
previously tested with anthropomorphic dum-
mies for automotive use. Each bag was folded
into a test instrument panel 10’’ forward of the
seated baboon (Fig. 1-F). Bag inflation was
initiated by electronic impulse as the sled probe
penetrated the brake system at impact. As the
subject came into contact with the bag during
impact, the bag was deflated through pressure
relief diaphragms on either side. This produced
a dynamic system with deflation occurring as
the occupant moved into the restraint during the
impact sequence. Air bag tests were designed
as paired tests, from 30g. to 50g. (avg. g., sled
acceleration), with one animal terminated im-
mediately post-impact (3-6 minutes), and the
second animal for each g-level allowed to sur-
vive for chronic post-impact monitoring. Two
of the latter were monitored for 4 weeks (and
one for 12 weeks) to allow any possible trauma
as a result of impact to become evident.

The upper torso inverted-Y yoke restraint
system consisted of a single lap belt with an
experimental upper torso harness. Strain gauges
were mounted on both sides of the lap belt to
record belt forces. The upper torso portion of


C. 3-Point System (Diagonal and Lap Belt
Combination). Since the 3-point restraint
(American) configuration (Fig. 1-C) has not yet
been used extensively in the United States, acci-
dent experience is still limited and injuries at-
tributed to this system have been infrequently
reported to date. A rupture of the spleen with
fracture of five ribs, a fractured sternum,* and
a hyper-flexion/hyper-extension cervical injury*’
have been reported as attributed to the American
3-point system. (In the American 3-point system,
both® ends of the diagonal and lap belt are at-
tached independently, while in the European
3-point system, there are only three points, one
end of the lap belt continuing upward to form
the continuous diagonal attachment.) Swedish
studies have reported few injuries due to this
system*7* and similar results have been reported
from England*® and Australia." In a Dutch
study, “three times as many chest. and leg in-
juries” were found for diagonal and 3-point users
as for lap belt users.? The major advantage of
the 3-point system over either the single diagonal
or the lap belt is that it offers additional protec-

tion by preventing flexion of the upper torso.
Disadvantages appear to be that it must fit the
occupant correctly to be effective, and that in
side impact, the occupant on the side opposite the
impact may slip out of the harness, while the
occupant on the near side might receive cervical
injury from neck impingement on the belt. Nev-
ertheless, 8 properly worn 3-point restraint sys-
tem is clearly an improvement over the lap
belt.97°8

Table III provides data for three forward-
facing, one 50° side-facing, and two 90° side-
facing tests of the American 3-point system. In
two forward-facing impacts at 20g. and 22g., no
injury was found in one case and slight injury
(pancreatic petechial hemorrhage, adrenal peri-
capsular hemorrhage. uterus broad ligament
hematoma) in the other. A third test at 30g.
(20° seat pitch, 74.2 ft./sec. velocity, 3,000 g./sec.
onset rate for 0.095 sec. duration) also resulted
in minor trauma (belt contusions—(Fig. 11)—
dural congestion). The diagonal and lap belt
combination appears to provide much better in-
jury protection at this level of impact than the

ss. .
x“

Frovre 9. Giant nuclei in the muscle fibers.

18


0.3 to 0.5g. activation is necessary because of
“panic braking” decelerations, not occurring in
aircraft.

Tests were started initially at 30g., due to the
estimated restraint capability of this system. At
this level, in forward impact, trauma was minor,
consisting of dural and lung congestion and
cardiac micro-hemorrhage. At 43g. trauma was
similar, except that a scapular fracture occurred
as a result of belt impingement over the shoulder.
Belt contusions were also observable. At 49
peak sled g., trauma was severe and probably
fatal. Bilateral avulsion of the pectoralis
muscles with severe contusions due to belt pres-
sure was marked, and a partial dislocation of
the humerus occurred. Dural congestion and
pericardial, adrenal, uterine, and abdominal wall
hemorrhages were found. Again, myocardial
fragmentation was observed.

One left sideward-facing impact was run at
32g., a severe side impact. An artifact occurred
when the subject’s head struck the side panel
upon rebound, resulting in fatal cranial fracture

and cerebral hemorrhage. Other trauma was not
significant and further tests should be conducted.

F. Air-Bag Restraint Tests. Nine tests with
seven subjects were run in the forward-facing
orientation (seat pitch 13°) with an experimental
air-bag restraint system (Fig. 1-F) developed
by Eaton, Yale & Towne, Inc.* Entrance ve-
locities ranged from 71 to 94.1 ft./sec. with onset
rates of 8,300 to 6,000 g./sec., and with durations
from 0.040 to 0.060 second. Peak g. forces varied
from 33 to 57g. (Table VI). Tests were started
at 33g., due to the anticipated capability of this
system. This system consisted of a lap belt re-
straint and an air bag, which was folded into a
panel 10’ in front of the subject (Fig. 12).
Upon impact, the bag inflated before the subject
began moving forward (Fig. 18). As impact
occurred, the gas was vented through two side
holes, forming a dynamic system, and gradually
decelerating the subject while distributing the
load over his body. These were, to our knowl-
edge, the first experimental tests of a dynamic
air-bag system under controlled simulated crash
conditions with living subjects.

#

hate
in,

im

Ficvre 11. Contusion resulting from impingement of 3-point restraint in 20g. impact at 60 ft./see. velocity.

15


PATHOLOGY OF TRAUMA ATTRIBUTED TO RESTRAIN'

SYSTEMS IN CRASH IMPACT

I. Introduction

Although restraint systems have been used for
over 50 years in military aircraft, and in some
form for about 113 years in lighter-than-air
types of vehicles, their use in other forms of
transportation has been relatively new. Such
systems have conclusively demonstrated their
overall protective value to vehicle occupants;
however, experimental evaluation of the various
systems is necessary for the design of improved
future systems, as well as for developing even
better protective use of present systems. In re-
cent years considerable attention has been focused
on the more sophisticated military restraint sys-
tems, and in particular on the protection of
rather specialized occupants of space vehicles.
Injuries reported in the past have primarily re-
lated to problems of high-speed ejection (vertical
+G,) decelerations involving vertebral trauma,
isolated clinical findings, or to by-products of
experimental studies involving other basic ob-
jectives.

Very little attention has been given to the type
and severity of injuries which may be attributed
to the vast majority of restraint systems more
generally used. Commercial airline transports
currently utilize only lap belts for passenger
protection as do almost all general aviation air-
craft in the United States, military troop trans-
ports, and military helicopter transports. Even
such advanced aircraft as the 350-passenger
Boeing SST, the 750-passenger Lockheed C5A,
and the 490-passenger Boeing 747 will have only
the lap-belt system in all but aircrew cockpit
positions. In addition, similar systems are now
being installed in some 8.5 million automotive
vehicles per year. Pilot populations such as the
Apollo astronauts, airline transport and military
pilots represent very select young male physical
types, and their restraint needs and injury toler-
ances may differ considerably from those of the

general population which include infants and
children, women, and the aged and infirm.

The work reported here was conducted on the
USAF 6571st Aeromedical Research Laboratory
Daisy Decelerator as a project of the Protection
and Survival Laboratory, Civil Aeromedical In-
stitute (CAMI), Federal Aviation Administra-
tion. These studies involved a series of related
investigations assessing the protection from im-
pact trauma provided by various restraint sys-
tems commonly found in aircraft and automotive
vehicles. The latter phases of this series also
included two experimental systems.

The initial project was designed to investigate
injury to the pregnant female and/or fetus due
to lap belt forces at impact. This question has
had some discussion, but very little clinical data
are available,** and no prior experimental study
has been conducted. The deceleration patterns
selected for this study were based upon the hypo-
thetical situation of a pregnant woman passenger
subjected to the impact forces of a specific type
of airline jet transport, at 175,000 Ibs. gross
weight, crash landing after losing power on one
engine at 200 feet altitude after takeoff (45°
body orientation, forward facing, 39g., 260 ft./
sec. impact velocity, and 0.125 seconds duration
of initial impact). The passenger was assumed
to be located in the first row of the first-class
section. Since this condition proved to be non-
survivable for the first experimental baboon sub-
ject protected by lap belt only, subsequent tests
were conducted at lower levels for this system,

The work reported in this study was supported by the Civil
Aeromedical Institute, Federal Aviation Administration, De-
partment of Transportation, Oklahoma City, utilizing the
facilities and cooperation of the 657Ist Aeromedical Research
Laboratory, Holloman AFB, New Mexico. The opinions ex-
pressed are those of the authors and do not necessarily reflect
the official viewpoints of the several organizations concerned.

The animals used for these experiments were lawfully ac-
quired and treated in accordance with the principles of Lab-
oratory Animal Care issued by the Animal Facilities Standards
Committee of the Animal Care Panel, U.S. Department of

Health, Education, and Welfare, Public Health Service, March,
1963,


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24


ACKNOWLEDGMENTS

The authors wish to gratefully acknowledge the support and assistance
of a number of organizations and individuals who contributed to the work
reported in this paper. We especially wish to thank Richard F. Chandler,
Capt. Richard Sonntag, M.D., and Capt. Peter Hanson, 6571st Aeromedical
Research Laboratory, Holloman AFB, New Mexico; Allan Katzberg, Ph.D.,
Chairman, Department of Anatomy, Southwest Foundation for Medical Re-
search, San Antonio; and Jeffry S. Life and Bruce Pince, Space/Defense
Corporation, Birmingham, Michigan. Pathological histology was conducted
at CAMI, except for one series of radiographic analysis made by Dr. F. R.
Birkhill, Detroit, specific tissue examinations made by Dr. Allan Katzberg,
Southwest Research Foundation, San Antonio, and selected brain tissues
studied by Dr. Raphael Cilento, Detroit.

AUTHORS

Richard G. Snyder, Ph.D., Highway Safety Research Institute, Institute
of Science and Technology, University of Michigan, Ann Arbor, Michigan.

Clyde C. Snow, Ph.D., Civil Aeromedical Institute, Federal Aviation
Administration, Department of Transportation, Oklahoma City, Oklahoma.

Joseph W. Young, A.M., Civil Aeromedical Institute, Federal Aviation
Administration, Department of Transportation, Oklahoma City, Oklahoma.

Warren M. Crosby, M.D., Department of Gynecology and Obstetrics,
University of Oklahoma School of Medicine, Oklahoma City, Oklahoma.

Col. G. Townley Price, USA (Ret.) D.V.M., Civil Aeromedical Institute,
Federal Aviation Administration, Department of Transportation, Oklahoma
City, Oklahoma.

Qualified requesters may obtain Aviation Medical Reports from Defense Documentation
Center. The general public may purchase from Clearinghouse for Federal Scientific and
Technical Information, U.S. Dept. of Commerce, Springfield, Va. 22151.


2

nm

10.

1.

13.

14,

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16.

. Bastiaanse. J. C. and Borromon, A.

|. CHANDLER,

. Crospy, W. M.

REFERENCES

. AIKEN, D. W.: Intestinal Perforation and Facial
Fractures in Automobile Accident Victims Wearing
a Seat Belt. J. Louisiana State Med. Soc. 115:
235-236, 1963.

. ALLGoop, M. A. and Snow, ©. C.: Serum Amylase

and Lipase Levels in Normal Savannah Baboons
(Papio cynocephalus), Am. J. Vet. Clin. Path. 2:
135-137, 1968.

. ARMSTRONG, R.: National Bureau of Standards Tests

at Holloman AFB, Unpublished data, 1967.
BacxstroM, C.: Traffic Injuries in South Sweden
with Special Reference to Medico-Legal Autopsies
of Car Occupants and Value of Safety Belts.
Chirurgica Scandinavica, Suppl. 308, 1963,

Statistical
Seatbel: Rapport
Wegtransport Middelen.

Study. Effectiveness (of)
RA1-TNO, Instituut Voor
Netherlands, 1966,

}. Brrrett, J, H.: Safety Belts for Motor Vehicles in

Vietoria, Med. J. Australia 1: 67, 1964.
Bouin, N, I.: A Statistical Analysis of 28,000 Acci-
dent Cases with Emphasis on Occupant Restraint

Value. Proccedings, 11th Stapp Car Crash Confer-
ence, Anaheim, California, SAE paper No. 670925,
1967.
. Bourke, G. The Efficiency of Car Safety Belts.

J. Irish Med, Assoc, 57: 110-117, 1965.
Bruntus, U. and Lanparen, S.: The Effectiveness of
Safety Belts. An Analysis of 210 Belt Cases. Nord
Med. 66 : 1500-1508, 1961.
Camppert, B, J. and Krarsere, J. K.: Seat Belt
Effectiveness in the Non-Ejection Situation, Pro-
ceedings, Seventh Stapp Car Crash Conference, ©. C.
Thomas, 1964,
Camppett, H. E.: The Automotive Seat Belt and
Abdominal Injury. Surgery 119: 591-592, 1964.

R. F.: The Daisy Decelerator, ARL
TDL 67-8, 657ist ARL, Holloman AFB, New Mexico,
1967.
Crark, N, P., Wets, E. B. Jr, Brinkcey, J. W., and
TempLe, E.: Lateral Impact Tolerance Studies
in Support of Apollo. Report I. AMRL Memo M-29,
Wright-Patterson AFB, Ohio. February, 1963.
Cocke, W. M. Jr. and Mryer, K. K.: Splenic Rup-
ture Due to Improper Placement of Automotive
Safety Belt. J. Amer. Med. Assoc. 183: 698, 1963.
Snyper, R. G., Svow, C. C., and
Hanson, P. G.: Impact Injuries in Pregnancy: I.
Experimental Studies. Amer. J. Obst. & Gynec.
101: 100-108, 1967.
Crossy, W. M.: Impact Injuries in Pregnancy.
Proceedings, Civil Aviation Medical Assoc., Oklahoma
City, 12-14 October, 1967.

27

17.

18.

19.

28.

29.

30.

31.

34.

. Frercner, B. D, and Bragpon, B. G.:

. Harte, L,:

Curr, J. F.: Complete Rupture of the Pancreas.
Brit. J. Surg. 126 : 386-388, 1945,

De La PeNa, A. and GotpzieHer, J. W.: Clinical
Parameters of the Normal Baboon. The Baboon in
Medical Research, Proceedings, Vol. II, pp. 379-389.
First International Symposium on the Baboon and
Its Use as an Experimental Animal. Harold Vagt-
borg, Ed., University of Texas Press, 1967.
DeHaven, H., Tourry, B., and Macrt, 8.: Aircraft
Safety Belts: Their Injury Effect on the Human
Body, Crash Injury Research of Cornell University
Medical College, 1953.

DvBors, E. F.: Safety Belts Are Not Dangerous.
Brit. Med. J. 2: 605, 1952.

J. R. S.: Seat Belts and Cervical Spondy-

. Experts,
losis, Practitioner 188 : 802, 1962.
 Encperc, A.: Injuries Caused by Safety Belts. A

Contribution
an Unusual Case.
1961,

Federal Aviation Administration. Chapt. 9, Shoulder
Harness Installations, Section 1. Restraint Systems.
Advisory Circular No. 43.13-2, Change 2, Effective
5/26/67, Acceptable Methods, Techniques and Prac-
tices—Aircraft Alterations.

to the Discussion with Reference to
Svensk. Lakartidin. 58: 884-886,

| Fish, J. and Wricut, R. H.: The Seat Belt Syn-

drome—Does It Exist? J. Trauma 5: 746-750, 1965.

. FisHer, P.: Injury Produced by Seat Belts; Report

of Two Cases, J. Occupat. Med. 7: 211-212, 1965.
Seat-Belt
Fractures of the Spine and Sternum. JAMA 200:

177-178, 1967.

|. Preeark, R. J., Kon, J. M., Forx, F. A., and Baker,

R. J.: Traumatic Disruption of the Head of the
Pancreas, Arch. Surg. 91: 5-18, 1965.

Garrert, J. W. and Braunstein, P. W.: The Seat
Belt Syndrome. J. Trauma 2; 222-238, 1962.
Gerritsen, R., Bropese, A. S., and Pezz1, P. J.:
Unusual Abdominal Injuries Due to Seat Belts.
J. of the Albert Einstein Medical Center 14: 63-66,
1966.

Gissane, W. and Butt, J.: A Study of Motor-Way
Fatalities. Brit. Med. J. 1: 75, 1964.

Goatrr, E.: Road Accidents. Geigy, Basle, Switzer-
land Unfallopfer im Stressenverkeher. Series Chir-
urgica Geigy, No. 5, 1962.

. HANSEN, O. M. and Rasmussen, P. S.: Traffic Acci-

dent with a Spleen Injury Associated with the Use
of a Safety Belt. Ugeskr. Laeg. 125: 771-778, 1963.
Traumatic Rupture of the Pancreas.
Med, Bull. of Vet. Admin. 21(1) : 227-229, 1944.

Hanrr, J. F. and Lisa, J. R.: Isolated Nonpenetrating
Injuries of the Pancreas. Ten Year Review of


were recorded, upon rebound, since the force was
distributed upon the subject’s back rather than
being concentrated at the harness, as in forward-
facing impacts. All runs were survived without
significant trauma, At 44g., extensive abdominal
bruising was the only injury which could be
directly attributed to the restraint. Despite
findings of intra-cranial hemorrhage in three of
the four cases, these injuries were considered
reversible (with the exception of the fetal death).
The rearward-facing body orientation offered the
best support in impact for the lap-belt-only re-
strained subject.

B. Diagonal Belt Tests. Tests with the single
diagonal belt only (Fig. 1-B) were made because
this restraint system has been reported used in
as much as 85% of Swedish automobiles.t This
system extends across the shoulder and chest on
the outboard side (left shoulder for driver, right
shoulder for passenger) diagonally across the
chest to the opposite hip, where it is anchored to
the floor. In our tests, the subjects received fatal

Figure 7.

i

trauma. This system not only does not provide
pelvic restraint, which allows the subject’s lower
torso to swing forward and rotate out of the belt
at impact (unless stopped by striking the instru-
ment panel, car door, or other structure), but in
side impact produces an extremely lethal whip-
ping action in which the body literally rotates
about and out of the belt. There have been sev-
eral studies of injuries attributed to this type of
belt—including data on chest injuries,4%**74%77
as well as ruptured spleen,** and sternal frac-
ture.?>

In our series, two forward-facing 30g. tests and
one sideward-facing 30g. test were run (Table IT,
A and B). As can be readily seen from the severe
trauma received in each case, this “restraint”
system certainly does not appear to offer many
advantages, and cannot be considered equal in
protective capability to the lap belt. In each
case, massive destruction of the thoracic cage
occurred, with extensive avulsion and rupture
of the pectoral muscles, numerous rib fractures,

bat ia,

Lacerations of liver typical of trauma in impacted subjects protected by a single diagonal belt only.


lap belt only which appears to offer marginal
survivability at 30g.

Two rearward-facing tests were run in this
configuration, At 20g. no injury was found. At
40g., injury was not severe (subdural hemor-
rhage, subcapsular kidney hemorrhage, and
petechial hemorrhages), and only the kidney and
rib petechial hemorrhages are attributable to the
belt. (in rebound).

After one 50° left side impact at 22g., mod-
erate intra-dural hemorrhage was found upon
gross examination, and myofibrillar degeneration
upon microscopic histological study.

Two 90° sideward-facing impacts (Table III-
D) at 22g. and 30g. were run. At the lower level,
severe dural and urinary bladder hemorrhage
occurred, in marked contrast to the 22g, forward
run where no trauma was found. At 30g. trauma
was instantly fatal, due primarily to dislocation
of the atlanto-occipital joint as the neck impinged
upon the diagonal belt.

D. Full-Torso Restraint. The full-torso re-
straint (Fig. 1-D) consisting of lap belt and

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double shoulder harness has been long utilized in
military training, and is required at flight deck
crew stations of airline transport aircraft. Such
systems have been extensively tested and have
been demonstrated to be extremely effective.2%%8?
Numerous versions (5-point, etc.) have evolved
from this basic configuration. Because of the
previously proven protective value of the full-
torso restraint, only one animal was run in this
series, and at 20g. neither gross nor microscopic
trauma was found (Table IV).

E. Inverted-Y Yoke Double-Shoulder Har-
ness. An experimental system, called the in-
verted-Y yoke double-shoulder harness, with
inertia reel, (Fig. 1-E) was also tested in a series
of three forward- and one 90° side-facing im-
pacts (Table V).% This system offers the ad-
vantages of full-torso support while allowing
free and complete movement of the occupant to
reach controls and change position. It is com-
fortable, easy to slip into without mussing clothes,
and fits women comfortably. Activation of most
aircraft reels occurs at 2g., but in automobiles,

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Interfibrillar edema and vacuoles in the myofibers are indicated by the lightly stained areas in longi-

tudinally sectioned fibers.

14