| Nerve | Key Muscle(s) | Action Tested | | :--- | :--- | :--- | | T1 | Abductor pollicis brevis, interossei | Finger abduction/adduction | | T2–T6 | Intercostals | Rib elevation (inspiration) | | T7–T11 | External oblique, internal oblique | Trunk rotation, sit-up | | T12 | Quadratus lumborum, transversus abdominis | Lateral trunk flexion |
The larger branch that becomes the intercostal nerves (T1–T11) or the subcostal nerve (T12). thoracic nerve distribution
The thoracic nerves originate from the thoracic spinal cord, specifically from the T1 to T12 vertebrae. Each thoracic nerve exits the spinal canal through the intervertebral foramen, which is the space between adjacent vertebrae. Once outside the spinal canal, the nerves divide into two main branches: the ventral ramus and the dorsal ramus. | Nerve | Key Muscle(s) | Action Tested
Dysfunction of the thoracic nerves can result in a range of clinical symptoms, including: Once outside the spinal canal, the nerves divide