Congenital kyphosis is due to the same embryologic failure of segmentation or formation of the vertebrae as congenital scoliosis. The direction of the curve (lateral or posterior) depends on the location of the spinal defect. Anterior defects cause kyphosis, and lateral defects cause scoliosis. A combined deformity, kyphoscoliosis, is common. In about 15% of patients, congenital deformities are associated with an anomaly of the neural elements (e.g., diastematomyelia, neurenteric cyst).