Georg Schmidt

QUANTIFICATION OF SIDE IMPACT RESPONSES AND INJURIES

Side impacts have been shown to produce a large portion of both serious and fatal injuries within the total automotive crash problem. These injuries are produced as a result of the rapid changes in velocity an automobile occupants body experiences during a crash. Any improvement to the side impact problem will be brought about by means which will ultimately modify the occupants rapid body motions to such a degree that they will no longer produce injuries of serious consequence. Accurate knowledge of both the bodys motion and resulting injuries under a variety of impact conditions is needed to achieve this goal. Possession of this knowledge will then permit development of accurate anthropomorphic test devices and injury criteria which can be used to create effective injury countermeasures in vehicles.

Human Response to and Injury from Lateral Impact

Lateral impacts have been shown to produce a large portion of both serious and fatal injuries within the total automotive crash problem. These injuries are produced as a result of the rapid changes in velocity that an automobile occupants body experiences during a crash. In an effort to understand the mechanisms of these injuries, an experimental program using human surrogates (cadavers) was initiated. Initial impact velocity and compliance of the lateral impacting surface were the primary test features that were controlled, while age of the test specimen was varied to assess its influence on the injury outcome. Instrumentation consisted of 24 accelerometer channels on the subjects along with contact forces measured on the wall both at the thoracic and pelvic level. The individual responses and resulting injuries sustained by 11 new subjects tested at the University of Heidelberg are presented in detail. An examination of the relationship between forces applied and responses observed in the thorax is discussed. The average injuries for different sled test conditions are presented based on a total of 42 cadaver tests (11 of which are the ones discussed above). The comparison of rigid wall and padded wall sled tests is made based on these average injuries. For the covering abstract of the conference see HS-036 716. (Author/TRRL)

Neck and thorax tolerance levels of belt-protected occupants in head-on collisions

Our tests with fresh human cadavers were continued (cf. proceedings, 18th Stapp Car Crash Conference). Presented herewith are the results of 103 tests evaluated so far. While the severity of injuries showed an increase with advancing age, it is not obviously dependent upon weight or sex. Under the conditions chosen by us, the 12 to 30-year age group reached the thorax tolerance level at an impact velocity of still below 50 kn/h with a stopping distance of 40 cm, the 30- to 50-year age group of below 40 km/h, and the age group beyond 50 years below 30 km/h. A comparison of our results with volunteer tests (Ewing et al., 29) and with evaluated real accidents (Patrick et al., 22) as well as with similar cadaver tests (Terriere et al., 19) is made. When introducing safety testing regulations for vehicles in the light of dummy tests, the broad spectrum of the respective age groups has to be considered. The thorax injuries may be slightly mitigated due to a lessening of the surface pressure. The injuries of the neck and thoracic vertebra, on the other hand are apparently not dependent on this factor and to a varying extent, are always occurring at an impact velocity of 50 km/h. Here too, the severity of the injuries increases according to the age. Therefore, it was set grant store by the recording of vertebral injuries. By employing careful dissection and preparatory-techniques, disc injuries, hemorrhages in the region of muscles and intervertebral joints were found in the majority of the cases, where as less frequently fractures of vertebral arcs and fractures of the processus spinosus and transversus, respectively were noticed. Highly dangerous vertebral injuries involving contusion or rupture of the cervical or thoracic spinal cord occurred only rarely. The Abbreviated ACIR scale proved to be sufficient for the graduation of the injuries. The grades ranging from 0 to 4 may well-be compared with the AIS scale with grades from 0 to 9 (AIS 6 - = fatal is equivalent to ACIR 4). States and Huelke (30) suggest the simplification and reduction of the AIS scale. They recommend a condensation of figures 6 - 9, thereby approaching the ACIR scale. By measuring the bone hardness and bending strength of the ribs, the skeleton injuries observed in the tests were related to the age-dependent resistance capability. In concluding, reports will be rendered on the photographic evaluation of the phases of movement recorded laterally by a high-speed camera, and on the legal basis of cadaver tests.

Rib-cage injuries indicating the direction and strength of impact☆

The hardness and loading capacity of hundreds of rib pairs have been tested and compared with the results of about 200 tests concerning belt-protected human cadavers. Rib fractures exhibit patterns that indicate the direction and strength of impact. Differences are seen between static and dynamic loading. Deformation of the loaded rib cage can be demonstrated by X-ray examination.

Belastbarkeit gurtgeschützter menschlicher Körper bei simulierten Frontalaufprallen

SummaryUtiliging a drop weight installation, frontal crashes with occupants wearing safety belts were simulated, using various harness systems. 10 male and female cadavers from 12 to 78 years were tested. Shoulder-belt-forces of 340–1000 kp and lap-belt-forces of 430–750 kp were measured by using crash velocities ranging from 50 to 79 km/hr, and a sled deceleration of 18.5 up to 31 g. Autopsy of young cadavers did not show any or only slight injuries; cadavers in the middle and old age groups showed not dangerous or dangerous injuries respectively. For young cadavers tested the chance to survive can be considered as good; for cadavers tested in the middle and old age groups survival chances can be considered as good to bad.ZusammenfassungUnter Verwendung verschiedener Gurtsysteme wurden Frontalaufpralle eines gurtgeschützten Beifahrers mit der Fallgewichtsbeschleunigungsanlage simuliert. Zur Verfügung standen 10 Leichen männlichen und weiblichen Geschlechtes im Altersbereich von 12 bis 78 Jahren. Bei Aufprallgeschwindigkeiten von 50 bzw. 79 km/Std mit einer Schlittenverzögerung, die zwischen 18,5 und 31 g lag, wurden Schultergurtkräfte von 340 bis 1000 kp, Beckengurtkräfte von 430 bis 750 kp gemessen. Die Obduktion ergab bei jungen Testobjekten keine bis leichte Verletzungen, bei Testobjekten im mittleren und Greisenalter nicht gefährliche bis gefährliche Verletzungen. Die überlebenschance für junge Testpersonen kann als gut, für Versuchsobjekte mittleren und Greisenalters als gut bis schlecht bezeichnet werden.

Rekonstruktion des Unfallherganges bei Halsverletzungen

SummaryBecause of a difficult postmortem examination, which requires much time, injuries of the neck are not always recognized distinctly. According to Weil (1968), the cervical vertebrae were injured by more than 50% of the traffic victims. Autopsy technique: The usual section of the scalp is lengthened behind the ears along the sternocleidomastoidmuscle to the manubrium sterni. In this way the superficial muscles of the neck may be well displayed. If a bone injury is suspected, x-ray examination must follow after removing the muscles in layers. By angiography of the arteriae vertebrates or carotides, suspected injuries of the vessels can be detected. The cervical and if necessary the breast and lumbar vertebrae are removed. Biomechanics. The biomechanic-functional unit, head — neck — trunk, exhibits this speciality that an acceleration or deceleration between head and trunk often takes place. Less frequent are the direct injuries of the neck. Acceleration works in axial and linear direction as pressure or tension. Muscle strainings, band lacerations and disruption of the vertebrae or the cranial base (circle fracture) occur. In case of tension the fragments of the os occipitale lay outside and in case of pressure within the cranial cavity. Forces as in the case of whiplash of following trunk impact work as rotational acceleration with the result of wringing off the neck. Dynamical tension loading of the cervical vertebrae with 160–360 kp results in disruption after lengthening from 6 to 11 cm, whereas pressure of 1350 to 1800 kp is needed for lacerations. So the violability is much greater by tension than by pressure.So far the description implies short (5–160 msec) and quick (> 15 km/hr or 1300 rad/sec2) motions according to dynamic impact. In case of quasi static pressure more fractures of the vertebral pedicles are detected, perhaps by shearing forces, to which the neck is exposed. The neck marrow can also be crushed vigorously, if vertebral bodies are dislocated. Injuries of the arteriae vertebrates are less frequent. Although measurements with reference to the loading capacity of the neck are known, experiments in a greater extent are nevertheless necessary. Reconstruction. Apart from the tensile lacerations which appear on the neck in front lateral following the cleavage directions of the skin, direct trauma to the skin of the neck is well known and is not to be discussed here. The tearing lines require some time for their formation. The nature of the injuries of soft tissues and — better — bones permits to recognize the dynamic (whiplash) or quasi static (pressure against abutment) origin. It is good to decide, whether the flexions of the neck were coming, from the front or the back or the sides. The locality of the lacerations illustrate well the direction of the hyperextension. These conclusions must be demonstrated by a critical examination of all details, for example the injuries of the head, damaging of cloths, foreign bodies in wounds and observations of intravital and post-mortal origin.ZusammenfassungEinige wichtige Kriterien bei der gerichtsmedizinischen Untersuchung von Halsverletzungen werden auf Grund eigener und der Literaturerfahrungen dargestellt. Besondere Beachtung gebührt einer geeigneten Sektionstechnik, der Biomechanik und den oft subtilen Verletzungsbefunden, damit eine optimale Rekonstruktion des Unfallmechanismus mö glich wird.

Zur Leistungsbeeinträchtigung durch Alkohol und Diazepam

SummaryAn investigation was carried out on the effect of the intake of diazepam and alcohol on simple performance tests. The combined administration of diazepam and alcohol led to an increase of the plasma diazepam concentration as compared to that obtained after diazepam without alcohol. Furthermore, after combined intake of diazepam and alcohol a decrease of performance was observed, that was significantly higher, than the effects obtained after either alcohol or diazepam alone. This impairment was especially noticeable during the first hour of the experiment, i.e. until the plateau of the diazepam plasma concentration was reached, while afterwards a correlation between diazepam plasma concentration and impairment of performance could not be established. The relevance of these findings for the interpretation of diazepam plasma concentrations in relation to the impairment of performance are discussed.ZusammenfassungIn einer an 65 Versuchspersonen durchgeführten Untersuchung wurde die Auswirkung der kombinierten Einnahme von Alkohol und Diazepam auf die Leistungsfähigkeit untersucht. Es zeigte sich, daß die Plasmaspiegel bei gleichzeitiger Einnahme von Alkohol und Diazepam höher waren als bei alleiniger Gabe von Diazepam. In gleicher Weise ergaben sich bei der Kombination beider Mittel höhere Leistungsbeeinträchtigungen als bei getrennter Einnahme von Alkohol und Diazepam. Die Wirkung war in der ersten Stunde nach der Medikation besonders deutlich und ging mit zunehmender Zeit zurück. Eine besondere Leistungsbeeinträchtigung besteht demnach in der Anflutungs- und früheren Plateauphase, während später trotz eines noch relativ hohen Plasmaspiegels weniger starke Leistungsminderungen nachweisbar sind. Die Bedeutung der Beziehung zwischen Plasmaspiegel und Leistungsbeeinträchtigung wird diskutiert.

Injury Patterns of Fatally Impacted Car Front Passengers in Regard to the Three-Point Seat Belt and Related Occupant Injury Modes

At the institute of forensic medicine of the university of heidelberg, post-mortems were performed on 117 victims who died in car crashes in the period from August 1, 1984 until July 31, 1986. This period was the initial two years of the seat belt law in the Federal republic of Germany requiring front seat car passengers to wear safety belts or be fined. The increased usage of safety belts from approximately 50% to about 94% was found to change injury patterns significantly. Injury patterns of belt-wearing occupants were found to differ markedly from those of unbelted passengers provided the passenger compartment remained uncompromised. A belted driver or front seat passenger in a frontal collision environment, sustains mostly trunk injuries whereas the same type of collision in the non-belted occupant involves head, lower and upper limbs, and pelvis. When legal aspects are involved, the medicolegal community is called upon more and more to answer two questions: (1) did the occupant wear a seat belt? And (2) what influence on the injury pattern would a correctly worn seat belt restraint have had?(Author/TRRL)

Behavior and Response of Wheel Chair, Passenger and Restraint Systems Used in Ruses During Impact

Frontal, lateral and rear-end collisions with dummy occupied wheel chairs on a deceleration sled were conducted in two test series at a collision velocity of 30 km/h, and a sled deceleration of 8 and 12 g. In the first dummy test series conventional restraint systems were used; in the second test series improved restraint systems were employed. In a further series, four cadaver tests were conducted. For all tests and collision directions the HIC values, as well as the resultant acceleration at the center of gravity lay below the admissible values of Federal Motor Safety Standard 208. Despite the low thorax accelerations numerous rib fractures occurred in the cadaver tests. In two cadaver tests, injury degrees of AIS 5 were observed (multiple liver ruptures, vertebral column injuries).