Intraspinal communication of sacrococcygeal dermal sinuses.

Three cases of sacrococcygeal dermal sinus are reported, all of which terminated in the filum terminale and two of which caused meningitis. Because of the frequent incidence of sacrococcygeal dermal sinus and the rarity of an intraspinal communication, the embryogenesis of sacrococcygeal dermal sinus is discussed in regard to caudal development of the dural sac and the filum terminale. Contrary to contemporary opinion, sacrococcygeal sinuses cannot be disregarded as a route for intraspinal infection.