Abstract: A head support apparatus for protecting the head of a subject positioned in a vehicle against the detrimental effects of acceleration. Generally, the invention comprises a beam housing attachable to a support device for supporting a subject's upper body while positioned in the vehicle. The beam housing has a side opening on each side thereof and a channel formed in the interior of the housing, extending from one side opening to the opposite side opening. Beam housing support is provided for rigidly supporting the beam housing to the support device within a y-z plane defined by the intersection of a y-axis and a z-axis, but allowing rotation about an x-axis. The x, y and z axes define an orthogonal coordinate system wherein the x-axis extends through the subject's face to the back of the head, the y-axis extends laterally from ear-to-ear, and the z-axis extends vertically from the top of the head through the subject's chin.