Correct answer:

This is usually an incidental finding noted on X-ray. When overlying skin changes (dimple, hair tuft, lipoma, sinus) are present, the cord beneath may be tethered to the skin by a fibrous band, and, as the child grows weakness in the legs may occur with sensory loss, pes cavus, or difficulty with bladder and bowel sphincters – ‘the tethered cord syndrome’.