RADIAL NERVE
- The radial nerve arises from the posterior cord of the brachial plexus.
- It runs down the posterior side of the arm & forearm.
- Innervates the post. part of the upper limb.
* Lower triangular
bordered laterally by the shaft of the humerus and medially by lat. border of long head of triceps.
Course:
In axilla and arm:
- Posterior to 3rd part of axillary a. and upper half of brachial a.
- It passes through the lower triangular space to run in Post. compartments of the arm in the spiral groove. (of the humerus)
- Pierces lateral intermuscular septum to go back to the ant. compartment in groove between brachialis & brachio-radialis muscles.
- Anterior to the lateral epicondyle of humerus. It ends by giving a superficial (sensory) and deep (motor) terminal branches.
Branches:
Proximal to spiral groove: (3 branches
- 2 muscular to triceps (Long & medial)
- 1 Post. cutaneous of arm.
In the spiral groove: (5 branches)
- 3 muscular: to triceps (lat. & med.) + anconeus.
- 2 cutaneus: lower lat. of arm + post. cut. of forearm.
Superficial terminal:
lateral 2/3 of dorsum of hand and dorsal surface of lateral 3½ fingers except nail beds.
Deep terminal:
- Reaches back of forearm by passing between two heads of supinator, winds around neck of the radius.
- Supplies ext. carpi radialis brevis & supinator (before piercing)
- Supplies the rest of the extensor compartment of the forearm (after piercing).