Spinal segmental dysgenesis: presentation of a rare spinal congenital abnormality.

Segmental spinal dysgenesis is a rare spinal congenital abnormality in which a segment of the spine and spinal cord fails to develop completely. This entity is often associated with other congenital anomalies such as multiple vertebral segmentation defects, congenital vertebral displacement, tethered cord, hydromyelia and syringohydromyelia.