Concept of a Neck Protective Device (CNPD).

During impact or sudden acceleration, the cervical and thoracic region of the spine of operators of Habitable Mobile Vehicles (HMV) may be exposed to extensive trauma since "whiplash"-type motion typically leads to impairment of a cervical joint. Furthermore, the frequent necessity of supporting added mass above the shoulders (e.g., crash helmet, displays, oxygen mask) can magnify the moment of inertia of the head. This additional mass affects the biomechanics of a Helmet-Head-Neck System and determination of the tolerable magnitudes of acceleration which it can undergo. Even if the body of the operator is restrained by seat belts, such acceleration can arise in all three vectors (Gx, Gy, and Gz). The population at risk for injury due to such forces are individuals exposed to forces generated in racing cars, involved in automobile impacts or emergency landing of aircraft, in normal landing on carriers or in piloting of 5th generation fighter planes, and in other aspects of operator activity in HMV. Various methods of fixation of the head to prevent cervical injury are described in the literature: cervical collars, inflated thoracic defensive members, airbags, cervical supports, etc. However, all of these have some deficiencies related either to one-time availability or the restricted range of head motion which they produce. Widely used automatic retaining systems composed of belts with forced pull and airbags, while successful in other regards, do not adequately protect the head and neck of the operators who are chronically exposed to iterated percussion, and other acceleration forces under diverse extreme conditions.