Nerve · Pelvis

Coccygeal nerve

Nervus coccygeus

The last and smallest spinal nerve — the thirty-first pair, and the end of a series that begins at the base of the skull. Its roots leave the very tip of the spinal cord's tapering end, travel down inside the dural sac as the lowest strands of the cauda equina, and emerge through the sacral hiatus. There it joins branches from the fourth and fifth sacral nerves to form the coccygeal plexus, a small network on the front of coccygeus, whose only output is the anococcygeal nerve to the skin over the tailbone. A whole spinal segment, in other words, whose entire remaining job is a patch of skin.