Spinal concussion has received various definitions during the last three quarters of a century. Hassin,1 who reviewed the literature in 1923, pointed out that the term is reserved by some authors for instances of injury to the back in which anatomic changes are produced in the spinal cord without the intermediation of direct pressure on the cord, and that it is not used by them for direct injury to the cord from hemorrhage or tearing or from a sudden bending of the spine, which compresses the cord but leaves the canal thereafter unchanged.
Histologic study of the condition began when Schmaus2 produced spinal concussion in rabbits and advanced with the subsequent confirmation of his work by Kirchgässer,3 Spiller4 and Jakob.5 These investigators demonstrated degeneration of the nerve fibers and foci of softening in spinal cords unaffected by compression or hemorrhage. More accurate observations became possible