The ratio of dorsal root ganglion cells to dorsal root axons in sacral segments of the cat.

Processes of dorsal root ganglion cells are depicted as being unbranched until they reach the spinal cord or periphery. This is an important concept because, for example, branching of these processes might be a basis for referred pain. Recently several studies indicate that axons of rat dorsal root ganglion cells branch in or near the ganglion. The present study extends this work by showing that there are approximately 1.4 dorsal root axons for each dorsal root ganglion cell in sacral segments of the adult cat, and these data are interpreted as indicating that many dorsal root axons in this animal also branch. Thus this study provides further evidence to indicate that a revision of our ideas about the organization of primary sensory cells is desirable. In addition, this study provides data to indicate that the numbers of both dorsal root ganglion cells and dorsal root axons differ on the right as compared to the left side of the same segment.