spina bifida occulta, defective closure of the laminae of the vertebral column in the lumbosacral region without hernial protrusion of the spinal cord or meninges. The defect, which is quite common, occurs in about 5% of the population. It is identified externally by a skin depression or dimple, dark tufts of hair, telangiectasis, or soft subcutaneous lipomas at the site. Because the neural tube has closed, there are usually no neurological impairments associated with the defect. However, any abnormal adhesion of the spinal cord to the area of the malformation may lead to neuromuscular disturbances, usually problems with gait and foot weakness and with the bowel and bladder sphincters. Compare spina bifida cystica.
