QS Study

A typical intercostal nerve is the anterior primary rami of 3rd – 6th thoracic spinal nerves, which supply only the thoracic wall, are called typical intercostal nerve. The thoracic wall is supplied by the 12 pairs of the thoracic spinal nerves. Anterior and posterior rami are formed as soon as they leave the intervertebral foramina.

Functional components – The contraction of the external intercostal muscles causes an elevation of the ribs whereas both the internal and innermost intercostal muscles to lower the ribs.

  1. General somatic afferent.
  2. General somatic efferent.
  3. General visceral afferent.
  4. General visceral efferent.

Location of the cell bodies: All spinal nerves including typical thoracic intercostal nerves are mixed nerve. The motor intercostal nerve is then identified in the mid-anterior chest region; it is located on the pleura behind the exposed rib periosteum, deep to the intercostal muscle at the caudal margin of each rib. They carry both motor & sensory nerve fibers.

  1. Cell bodies of motor fibers are located at the anterior horn of gray matter of ‘spinal cord.
  2. Cell bodies of sensory fibers are located at the dorsal root ganglia.