A method of protecting the posterior neck and cervical spinal cord from injury when the torso of the user is restrained with respect to selected points on a fixed structure, when subjected to sudden deceleration or acceleration forces, by engaging the chin/forehead of the person's head with portions of a crash helmet, and transmitting the reaction forces bearing on said forehead and chin via said crash helmet and a flexible connection having a predetermined degree of stretch, coaxially along a single line passing only through the superior nuchal line on the back of the skull and substantially perpendicular to the axial line of the vertebrae-skull in the normal erect posture of the user, whereby rapid angulation movements of the head and neck do not occur during sudden forward-deceleration or upward-acceleration with ejection seat usage.Ģ. Thus, the restraint is along a line passing through a very small zone located at the lower central posterior area of the back of the head.ġ. The slight forward movement of the head and neck allowed by soft/medium webbing will attenuate the forces applied to the head and neck junction during forward-deceleration or upward vertical ejection-acceleration (from a military high performance fighter/bomber aircraft). The webbing for the inertial reel connection is preferably medium to soft. The helmet includes forehead padding, a wrap around cup shaped chin strap and an adjustable nape strap.
Such lethal injuries according to the invention are prevented by a single inertial reel connection to the helmet of the user, at a point, aligned with or slightly above the superior nuchal line of the skull of the user. The neck of human beings is at risk from lethal spinal cord injury with rupture of the atlanto-occipital membrane which holds the base of the skull to first cervical vertebra. The invention relates to an improved ejection seat restraint system for protecting the head and neck and spinal cord from injuries resulting from rapid forward deceleration and ejection from aircraft.