During the course of dissection of the filum terminale at autopsy in about 30 adults 5 cases of cysts (neither parasitic nor dermoid) on the extradural portions of the posterior sacral or coccygeal nerve roots were encountered. Since but 2 reports of similar cysts have come to my attention, this experience seems worth recording, particularly since it was possible to determine the site of origin of the cysts in these cases.
Marburg1 described 4 cases of cysts of the spinal ganglia. The cysts were solitary in 3 cases and multiple in the fourth. Hinrichs2 recorded a case in which 3 cysts occurred on the posterior thoracic and lumbar roots, in the region of junction of the root and the ganglion. The subjects were between 61 and 77 years of age and presented no symptoms referable to the cysts. Marburg concluded that it was likely that the cysts followed