Branching of sensory axons in the dorsal root and evidence for the absence of dorsal root efferent fibers.

The present study demonstrates that there are more dorsal root axons than dorsal root ganglion cells in the L6-S1 dorsal roots of the rat. The excess fibers do not come from aberrant dorsal root ganglion cells and our control procedures indicate that there are no extraneous fibers in these dorsal roots. Accordingly many dorsal root axons must branch in the dorsal root.