Superior Lateral Brachial Cutaneous Nerve, Posterior View

Description

Positioned on the posterolateral shoulder, the superior lateral brachial cutaneous nerve (the cutaneous branch of the axillary nerve) emerges deep to the deltoid and pierces the deep fascia near the posterior border of the muscle to enter the subcutaneous tissue. From there it fans distally over the proximal lateral arm, superficial to the deltoid fascia and adjacent skin territory, while remaining lateral to the long head of triceps and posterior to the surgical neck region of the humerus. Portions of the posterior deltoid and neighboring rotator cuff contour are visible, with accompanying axillary-region vessels tracking in close proximity to the nerve’s parent trunk. Posterior visualization matters because it clarifies where the axillary nerve and its superior lateral cutaneous branch pass around the humerus in the quadrangular space, bordered by teres minor superiorly, teres major inferiorly, the long head of triceps medially, and the surgical neck of the humerus laterally. That corridor is a common site of injury in anterior shoulder dislocation and proximal humeral fractures, and it is also at risk during a posterior or deltoid-splitting approach, where an injection placed too high can injure the nerve and produce numbness over the “regimental badge” area. Small territory, big diagnostic payoff. Use this artwork for teaching upper limb dermatomes and peripheral cutaneous nerve fields in gross anatomy and regional anesthesia modules, or for illustrating axillary nerve palsy, quadrangular space syndrome, and safe deltoid intramuscular injection landmarks in clinical skills materials. It also suits orthopedic and sports medicine publications discussing posterior shoulder exposure and postoperative sensory findings. Anatomical accuracy verified by SciePro's Medical Advisory Board.