The nerve supply to the upper limb is derived from the brachial plexus (formed by ventral rami of C5 to C8 and T1 spinal nerves). The five main branches of brachial plexus are axillary, musculocutaneous, median, ulnar, and radial nerves.
- The axillary nerve supplies the deltoid and teres minor muscles.
- The musculocutaneous, median, and ulnar nerves supply the muscles of anterior (flexor) compartments of the arm and forearm.
The radial nerve supplies the muscles of the posterior (extensor) compartments of the arm and forearm.
All the intrinsic muscles of the hand are supplied by the ulnar nerve except muscles of thenar eminence and first two lumbricals.