Cutaneous nerve anatomy relevant to lateral arm flap surgery.

BACKGROUND: The inferior lateral brachial cutaneous nerve (ILBCN) and posterior antebrachial cutaneous nerve (PACN) are clinically relevant during lateral arm flap elevation and procedures involving the distal arm and lateral elbow. However, their anatomy remains inconsistently described. This study aims to clarify the origins, courses, and anatomical relationships of the ILBCN and PACN to reproducible surgical landmarks. METHODS: Twenty-one upper extremities from twelve embalmed adult body donors were dissected. The ILBCN and PACN were traced from their origin at the radial nerve to their superficial distribution. Relationships to the lateral head of the triceps brachii, lateral intermuscular septum (LIMS), brachial fascia, distal deltoid attachment, and lateral epicondyle were documented. RESULTS: The ILBCN and PACN arose from a common trunk in 52.4% of specimens and separately in 47.6%. The ILBCN most commonly pierced the LIMS and became superficial in the anterior compartment (57.1%). The PACN most frequently became superficial posterior to the LIMS after piercing the distal attachment of the lateral head of the triceps brachii (61.9%). At the interepicondylar line, the PACN lay 15.6 ± 5.7 mm anterior to the lateral epicondyle. An overlapping cutaneous pathway supplying both ILBCN and PACN territories was identified in five specimens (23.8%). CONCLUSIONS: The ILBCN and PACN demonstrate reproducible anatomical relationships relevant to lateral arm flap elevation, sensory reconstruction, and preservation of donor-site sensibility. The overlapping cutaneous pathway identified in this study may contribute to variability in postoperative sensory outcomes involving the lateral arm and posterior forearm.