Caudal regression syndrome with sacral rib: MRI features.

Caudal regression syndrome (CRS) involves improper and incomplete development of distal spinal segments. Sacral rib is an unusual entity, where an accessory rib arises from the sacral vertebral segments. Very few cases have been described in the English literature. We present the case of a 3-year-old girl presenting with urinary and bowel incontinence and difficulties in walking with left-sided sacral rib, terminal cord syrinx, and caudal regression syndrome, involving sacrococcygeal segments, diagnosed on MRI. The association is not well illustrated in previous reports.