The Anatomy Of The Posterior Surface Of The Humerus

Description

Across the posterior aspect of the humerus, the animation tracks along the proximal-to-distal shaft, orienting you to the posterior surface between the posterolateral and posteromedial borders. A shallow, oblique radial groove (sulcus nervi radialis) becomes the central landmark as it courses inferolaterally across the midshaft, separating the origins of the lateral and medial heads of triceps brachii. The sequence continues distally to the posterior distal humerus, where the shaft widens toward the supracondylar ridges and the posterior fossa region above the trochlea and capitulum. Bony topography stays in posterior anatomical position throughout. Clinically, the radial groove matters because the radial nerve and profunda brachii artery track directly against bone at this level, making them vulnerable in midshaft fractures and iatrogenic injury during posterior approaches to the humerus. Motion in the animation clarifies how the groove sits obliquely relative to the long axis of the shaft, and how its relationship to triceps origins creates a consistent corridor for safe dissection when identifying the nerve. This is the anatomy behind wrist drop after a spiral fracture. Use it when teaching upper limb osteology, surface anatomy, or posterior compartment of the arm in gross anatomy and orthopedic modules, and as a quick reference for surgical trainees preparing for humeral shaft fixation, radial nerve exploration, or posterior plating approaches. It also pairs well with radiology teaching on AP and lateral humerus projections by reinforcing where the radial groove lies in 3D space. Anatomical accuracy verified by SciePro's Medical Advisory Board.