Fracture of a vertebral body end plate and disk protrusion causing subarachnoid block in an adolescent.

An apparently unique case of retroprotrusion of a portion of the vertebral end plate plus L4 disk in a 16-year-old boy demonstrated a complete myelographic block. The block was produced by a large fragment of bone which had broken off the inferior end plate of the body of L4 and was protruding into the spinal canal. Removal of the bony block and protruding disk resulted in complete resolution of symptoms.