Anatomical Location Of The Radial Groove On The Humerus

Description

Radial (spiral) groove on the humeral shaft is highlighted along the posterior surface of the mid-diaphysis, curving inferolaterally between the medial and lateral aspects of the bone. Proximal to it, the posterior humerus transitions toward the surgical neck and the posterior region adjacent to the greater tubercle, while distal to it the shaft narrows toward the supracondylar ridges. The depression sits deep to the lateral head of triceps brachii and approaches the lateral intermuscular septum as it tracks toward the distal arm. A shallow channel, but a loaded neighborhood. Clinically, this is the corridor for the radial nerve and profunda brachii artery, so its surface anatomy is tied directly to neurovascular risk in humeral shaft trauma and posterior arm surgery. Transverse or spiral diaphyseal fractures at the midshaft, and the classic distal-third pattern often discussed with Holstein-Lewis injuries, can injure the radial nerve where it lies against bone in or near the groove, producing wrist and finger extensor weakness with dorsal hand sensory loss. The fixed posterior perspective of the illustration helps learners map the groove to palpable diaphyseal landmarks and understand why the nerve becomes more superficial as it nears the lateral supracondylar region. Orthopaedic and trauma teaching materials can pair this illustration with exam findings for radial nerve palsy, plating corridors, and safe zones for posterior and anterolateral approaches to the humerus. It also fits upper-limb osteology labs, surgical anatomy chapters, and MCQ stems that test relations of the radial nerve to the humerus and triceps. Anatomical accuracy verified by SciePro's Medical Advisory Board.