Multiple meningeal diverticula and cysts associated with duplications of the sheaths of spinal nerve posterior roots.

Multiple diverticula and cysts of the meninges were found during an anatomical dissection. They were associated with duplications of sheaths of the posterior roots of the spinal nerves. The diverticula and cysts appeared as simple flaccid corrugated dilatations of the sheaths, as ampullary expansions, as pediculated cysts, or as saccular dilatations of different sizes and locations. The duplication of the sheaths affected posterior roots of the thoracic nerves only. Some variations of the sheaths described in the literature are discussed. The possibility is considered that both conditions result from the same pathological factors in the embryo.