Radial Groove Of The Humerus, Posterior View

Description

Radial groove anatomy dominates the posterior midshaft of the humerus, with the sulcus spiraling inferolaterally across the posterior surface between the medial and lateral aspects of the diaphysis. Proximal to the groove, the posterior surface broadens toward the region of the deltoid tuberosity laterally, while distally the shaft narrows toward the supracondylar ridges that lead to the medial and lateral epicondyles. The groove’s course places it posterior and slightly lateral relative to the shaft’s central axis, a relationship that becomes easier to appreciate when the humerus is isolated in a strict posterior perspective. Bony topography is the point. Clinically, this is the segment of the humerus that keeps surgeons and examiners honest because the radial nerve and the profunda brachii artery (deep artery of the arm) travel together in the spiral groove before the nerve pierces the lateral intermuscular septum to enter the anterior compartment. Midshaft humeral fractures, compression from prolonged immobilization (classically “Saturday night palsy”), and posterior approaches to the humerus all hinge on knowing where this groove sits relative to the diaphysis and the distal landmarks. Surface lighting that separates cortical contours from background helps the viewer track the sulcus without confusing it for the nutrient foramen or for irregularities at the muscle attachment areas. Use this illustration in upper limb osteology labs, anatomy and radiology teaching files on humeral shaft fractures, and operative anatomy references for posterior or lateral exposure where radial nerve protection is emphasized. It also suits orthopedic patient education materials that explain why wrist and finger extension weakness can follow a midshaft injury. Anatomical accuracy verified by SciePro's Medical Advisory Board.