Inferior Lateral Brachial Cutaneous Nerve, Lateral View

Description

Running in the lateral arm, the inferior lateral brachial cutaneous nerve branches from the radial nerve in the region of the humeral radial groove, then courses superficially to supply skin over the inferolateral aspect of the upper arm near the lateral epicondyle. Deep to it, the triceps brachii, most prominently the lateral head, occupies the posterior compartment, with tendon fibers converging distally toward the olecranon. Anteriorly and slightly medial in this lateral perspective, the brachialis and biceps brachii margins may appear as layered muscular planes, while superficial veins track within the subcutaneous tissue overlying the lateral arm. Orientation is clear. Proximal to distal. Clinically, this small sensory branch matters because it sits near common landmarks for posterior approaches to the humerus and for procedures performed around the radial groove. Fractures of the midshaft humerus or surgical exposure for plating can injure the parent radial nerve and its cutaneous branches, producing numbness over the lateral arm that can be mistaken for lateral antebrachial cutaneous nerve symptoms or for referred pain from lateral epicondylitis. This lateral view also helps explain why posterior intramuscular injections or deep dissections in the triceps interval risk neuropraxia when the dissection drifts too close to the spiral groove. Use this illustration for upper limb anatomy teaching in gross anatomy, neuroanatomy, and regional anesthesia modules when you need to separate radial nerve motor findings from purely cutaneous sensory loss. It also fits operative atlases and patient education materials describing humeral shaft fracture complications and posterior arm surgical corridors. Anatomical accuracy verified by SciePro's Medical Advisory Board.