The pia mater - a conduit for regenerating axons after ventral root replantation.

Previous studies have shown that replantation of avulsed ventral roots may lead to functional reinnervation of hindleg muscles. Regenerating motor axons may regrow for a considerable distance within the spinal cord before entering the replanted ventral root. In this study we show, in the rat and monkey, that many regenerating axons utilize an alternative pathway along the surface of the spinal cord, i.e. the pia mater. This type of reinnervation takes place entirely in the peripheral nervous system.