The intercostal nerves are the anterior divisions of the thoracic paravertebral nerve (T1 to T12). The intercostals supply sensory processes for the thoracic pleura and abdominal peritoneum. each intercostal nerve runs its own independent course without plexus formation. A branch from the twelfth nerve, also call the subcostal nerve, joints the first lumbar nerve to contribute to the lumbar plexus.
Points of injection are determined by interpreting peripheral areas of pain and tenderness, paravertebral tenderness and the landmarks of the spine.