Central nervous system of a thoracopagus.

Postmortem examination of the central nervous system (CNS) of a dicephalus thoracopagus tetrapus revealed two separate brains and spinal cords. On the conjoined side the spinal cord showed hypoplasia of the anterior horns and dorsal funiculi at the lower cervical and upper thoracic levels. Hypoplasia of the peripheral nerves, anterior horn cells, and dorsal funiculi is a consequence of a reduction in tissue mass due to a loss of inductive influence.