Currently available biomechanical data are insufficient for determining the neck loads required to produce cervical injuries in automotive accidents. The purpose of this study was to initiate a series of experiments required for identifying injury mechanisms and to develop criteria suitable for representing the spectrum of significant functional and structural neck injuries that could be sustained by car crash occupants. The first test conducted was a static neck tension test performed on an anesthetized, 12.2-kg baboon (Papio hamadryas). A state of muscle paralysis was maintained throughout neck loading to mimic the flaccid muscle tone present in fresh human cadavers. Tensile neck loading was increased at a rate of 20.2 N every five minutes until definitive structural failure (atlas-occipital subluxation) occurred at the 1170 N load level. Neurophysiological testing in the anesthetized animal demonstrated that cervical spinal cord function was seriously impaired at the 595 N load level, i.e., at 51 percent of the structural failure load. The potential implications of this finding are discussed, relative to the understanding of injury mechanisms. In addition, a strategy is presented for deriving functional neural tissue impairment thresholds, from fresh human cadaver data, that may apply in real accident victims.