Intercostal Nerves

nervi intercostales

The twelve pairs of thoracic nerve anterior rami are called intercostal nerves (T1 through T11) and subcostal nerve (T12), each running in the costal groove of the rib above between the internal and innermost intercostal layers. They supply the chest wall muscles and provide dermatomal sensation to the thorax and upper abdomen in horizontal bands. The classic dermatomal map of the chest is T4 at the nipple line, T7 at the xiphoid, T10 at the umbilicus, and L1 at the inguinal ligament.

Region: Chest

Anatomical Data

Origin, Insertion & Supply

Origin	Anterior rami of thoracic spinal nerves T1 through T11

Clinical Relevance

Clinical Notes

Intercostal nerve blocks provide analgesia for rib fractures, post-thoracotomy pain, and intercostal neuralgia from herpes zoster. Herpes zoster reactivation in an intercostal nerve produces the classic dermatomal chest wall pain and vesicular rash (shingles). Post-herpetic neuralgia from persisting intercostal nerve damage is a significant chronic pain condition managed with antivirals, tricyclic antidepressants, and nerve blocks.

Pathology

Common Injuries & Conditions

Intercostal Neuralgia

Persistent intercostal nerve pain from shingles, rib fracture, or thoracic surgery producing dermatomal chest wall pain and allodynia managed with analgesics, antivirals, and nerve block.