Spinal Nerves Vs. Medial Nerves

The human body has 31 pairs of spinal nerves. The medial nerves, also called the medial nerve branch block, transmit a pain message from the facet joints and muscles around the joints.

Spinal Nerve Locations

• Patrick McCaffrey, professor of the Communication Sciences and Disorders Graduate Program at California State University, Chico, identifies the locations of the spinal nerves: Eight pairs of nerves are found at the top of the spinal cord; 12 in the thoracic region; five each in the lumbar and sacral regions; and one in the coccygeal area.

Nerve Roots

• The spinal nerves "have both a sensory and a motor aspect," McCaffrey writes. The motor fibers attach to the anterior side of the spine's gray matter, while the roots of the sensory fibers are found in the posterior root ganglia.

Spinal Nerve Function

• The spinal nerves make up the "final common pathway" as messages travel from the central nervous system, and provide impulses to the lower body, according to McCaffrey.

Facet Joints

• Medial branch nerves carry messages from the facet joints. These small joints in the back of the spine form the connections between each vertebra, explains the Dartmouth-Hitchcock Medical Center, and determine your neck's range of motion.

Medial Injections

• The Permanente Medical Group says medial branch nerves "do not control any muscles or sensations in your arms or legs," meaning a medial branch block injection for lower back pain won't impair movement elsewhere.