Each spinal nerve has both sensory and motor fibers. The ramus communicantes, which contains both the GVA and GVE fibers joins the spinal nerve at this point completing each spinal nerve. Immediately after leaving the intervertebral foramen, each spinal nerve divides into an anterior and a posterior branch. The larger anterior branches supply the muscles and skin of the rest of the torso and the extremities. The spinal cord mediates a number of reflexes.
Reflexes are pre-programmed stereotypical responses to specific sensory stimulation.
Respiratory muscles are supplied by the spinal nerves. The phrenic nerve, which is formed by motor fibers of C4 - C5 innervate the diaphragm. Lumbar nerves supply the legs and the sacral nerves control the bowel, bladder and sexual functions. The sensory functions of these body parts - touch, pressure, pain, temperature, etc. The dorsal column tract consisting of fasciculis cuneatus and fascuculis gracilis carry discriminative touch, proprioception, stereognosis and position sense.