Neck and Thorax Tolerance Levels of Belt-Protected Occupants in Head-On Collisions 751149

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 km/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 (Tarriere 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 great 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 bodies, 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 - 9 = 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, 7, 8 and 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.