Superior Lateral Brachial Cutaneous Nerve, Posterior View

Description

Arising as the terminal cutaneous branch of the axillary nerve, the superior lateral brachial cutaneous nerve is shown from a posterior shoulder and arm perspective as it curves around the surgical neck of the humerus and emerges superficially along the posterolateral aspect of the proximal arm. The scapula sits medial to the proximal humerus, with the thoracic spine and posterior ribs forming a midline and thoracic backdrop. Proximally, the axillary nerve’s relationship to the posterior circumflex humeral vessels is implied by the nerve’s course toward the quadrangular space, then distally the cutaneous branch fans into the skin over the inferior deltoid region. Surface territory is the focus. Clinical relevance centers on localizing sensory change over the “regimental badge” area after shoulder trauma or surgery, where axillary nerve injury can follow anterior glenohumeral dislocation or fracture at the surgical neck of the humerus. A posterior view clarifies why the nerve becomes vulnerable as it exits deep to the deltoid and pierces the deep fascia, and it helps distinguish axillary nerve-related sensory loss from posterior radial cutaneous nerve symptoms that track farther down the posterior arm. For teaching, the distinction between motor branches to deltoid and teres minor and the superior lateral brachial cutaneous branch is easier to make when you can follow the nerve to its superficial emergence. Useful for brachial plexus and peripheral nerve modules in gross anatomy, physical diagnosis teaching on shoulder injuries, and orthopedic or sports medicine publications discussing axillary nerve risk during deltoid-splitting approaches and intramuscular injections. It also supports patient-facing diagrams for post-dislocation numbness patterns when kept at an appropriate level of simplification. Anatomical accuracy verified by SciePro's Medical Advisory Board.