spina bifid a (spi'nah bi'fid-ah)

A congenital malformation caused by absence or deficiency of the laminae or spinous proce es of some of the vertebrae, usually a ociated with a sacculated protrusion of the membranes of the spinal cord. The sac contains cerebrospinal fluid and sometimes a portion of the cord, false s. b. Any congenital tumor communicating with the spinal canal but not with the spinal membranes, s. b. cervical is. S. b. of the cervical vertebrae, s. b. completa. A form in which the medullary groove fails to close in to form the neural canal. The ependyma and nerve substance remain in contact with the skin, s. b. completa partial is. S. b. completa only in the cervical region, s. b. completa restrict a. S. b. affecting only a local area in the cervical or lumbar region, s. b. completa total is. A form in which the neural canal is present as a broad plate, extending down the back and fusing on either side with the skin of the back. s. b. cystic a. S. b. with the protrusion of a cyst through the fi ure. s. b. dorsal is. S. b. of the dorsal vertebrae, s. b. in comp let a. A form in which the neural canal has closed, but the laminae and the surrounding ti ues have failed to close, s. b. lumbalis. S. b. of the lumbar vertebrae, s. b. lumbosacral is. S. b. of the lumbosacral region, s. b. sacral is. S. b. of the sacral vertebrae.