The cord in humans may be likened to a coaxial cable, about one inch in diameter, and is a continuation of the brain. It looks like firm, white fat; nerves extend out from the cord to the muscles, skin and bones, to control movement, receive sensations and regulate bodily excretions and secretions. The 31 pairs of Spinal nerves divide the cord into the following segments: 8 Cervical, 12 Thoracic, 5 Lumbar, 5 Sacral, and 1 coccygeal.