| Function | C8 Nerve Root | T1 Nerve Root | | :--- | :--- | :--- | | | Finger flexors (FDS, FDP to middle/ring/little fingers), hand intrinsics (interossei, lumbricals 3&4), thumb adductor (adductor pollicis), long thumb flexor (FPL). | Hand intrinsics (thenar muscles – via median nerve; hypothenar & interossei – via ulnar nerve). T1 contributes significantly to median-innervated thenar bulk. | | Sensory | Medial forearm (medial antebrachial cutaneous), ring and little fingers (ulnar distribution, dorsal and palmar aspects). | Medial arm (medial brachial cutaneous) and variable contribution to medial forearm; minimal discrete autonomous zone but overlaps C8. | | Reflex | No deep tendon reflex is purely C8/T1. The finger jerk (flexor reflex) is partly mediated by these roots. | Same as C8. |
Shortly after exiting the intervertebral foramina, the C8 and T1 roots join to form the of the brachial plexus. From this trunk, nerves branch out to supply specific muscles and skin areas. This anatomical grouping explains why C8 and T1 pathologies often present with similar symptoms—an injury to one frequently affects the other. c8 t1 nerve roots
Although there are only seven cervical vertebrae, there are eight pairs of cervical nerve roots. The C8 nerve root is unique because it exits the spinal column (between C7 and T1). It is the final cervical nerve before the thoracic nerves begin. | Function | C8 Nerve Root | T1