Thoracic Nerve Distribution -

| Nerve | Region | Key Motor Targets | Key Sensory (Dermatome) | | :--- | :--- | :--- | :--- | | | Superior thorax | Intercostals, hand muscles (via T1 contribution to brachial plexus) | Medial forearm/axilla | | T2 | 1st-2nd intercostal space | Intercostals | Upper chest, axilla (intercostobrachial nerve) | | T3-T6 | Upper thorax | External/internal intercostals | Anterior chest wall (nipple = T4) | | T7-T9 | Mid-lower thorax | Intercostals, serratus posterior inferior | Epigastrium (xiphoid = T6) | | T10 | Subcostal region | Abdominal obliques, transversus abdominis | Umbilicus (landmark) | | T11-T12 | Lower thorax/flank | Abdominal muscles, quadratus lumborum | Hypogastrium, inguinal region |

Medical Education / Clinical Reference Date: [Current Date] Reviewer: Senior Anatomist / Neurologist thoracic nerve distribution

The thoracic spinal nerves (T1–T12) are unique within the spinal nerve hierarchy due to their organized segmental distribution. Unlike the plexuses found in the cervical or lumbosacral regions, thoracic nerves maintain distinct dermatomes and myotomes. They provide motor innervation to the intercostal and abdominal wall muscles, sensory innervation to the thorax and abdomen, and autonomic functions via the sympathetic chain. This report details their anatomy, pathways, and clinical significance. | Nerve | Region | Key Motor Targets