Role of Gelatinous Substance of Spinal Cord in Conduction of Pain

THE PATHS of the dorsal root fibers into Lissauer's zone and the dorsal funiculus of the spinal cord are well established. The manner of the termination of these fibers within the gray matter of the spinal cord and the pattern of the connecting neurons are not so well understood. This is particularly true of the human spinal cord. Although this problem has been studied by Ramón y Cajal,¹Ranson,²and others, there are still wide gaps in our knowledge of these connections. The majority of the studies on this subject have been based on the lower vertebrate forms, such as the chick and cat, with few observations on the higher mammals and man. Since the early literature on this subject has been reviewed by Barker³; Ranson⁴; Massazza⁵; Bok,⁶and Ariëns Kappers, Huber, and Crosby,⁷only the more recent investigations will be discussed. MATERIALS