Intercostal nerve (T2–T6) (ICN (for Intercostal nerve); no specific abbreviation for T2–T6 subset)

The intercostal nerves T2–T6, part of the somatic nervous system, arise from the anterior rami of thoracic spinal nerves T2 through T6. These mixed motor and sensory peripheral nerves run along each corresponding rib's costal groove between muscle layers in the chest wall. Their primary function is segmentally supplying motor fibers to the intercostal muscles responsible for respiration and providing sensory innervation from skin overlying the chest wall as well as parietal pleura lining inside the rib cage. They also carry sympathetic fibers that regulate sweat glands and blood vessel tone within their dermatomes. Clinically, they may be targeted with local anesthetic injections for surgical anesthesia or pain management but do not represent molecular targets suitable for pharmacological modulation by systemic drugs.

Other names

Thoracic intercostal nerve (T2–T6)Anterior rami of thoracic spinal nerves T2–T6Segmental thoracic nerves (T2–T6)

For local anesthetics: Blockade of voltage-gated sodium channels on axons within the nerve to prevent action potential propagation and thus sensory/motor transmission