Humerus Showing The Lateral Border

Description

Humeral shaft anatomy is centered on the lateral border (margo lateralis), the narrow longitudinal ridge that separates the anterolateral and posterolateral surfaces from the proximal surgical neck region down toward the distal lateral supracondylar ridge. In this lateral perspective, the border reads as a straight, palpable crest along the outer arm, with the deltoid tuberosity positioned slightly anterior to it at midshaft and the lateral epicondylar region lying distal and inferior. Proximally, the greater tubercle and shaft contour define the lateral shoulder profile, while the distal flare toward the capitulum side frames the lateral elbow. A clean bony landmark. That lateral border matters because it anchors orientation when teaching surface anatomy of the arm and when describing fracture morphology on radiographs and CT. Spiral and oblique shaft fractures often propagate along cortical lines, and the relationship of the lateral border to the posterior radial (spiral) groove helps learners anticipate where the radial nerve and profunda brachii artery course relative to the posterolateral cortex, a recurring concern in midshaft humeral fractures. The fixed lateral lighting in the illustration helps separate the ridge from adjacent surfaces so you can point out what is border versus tuberosity versus distal crest without relying on labels. Orthopedic teaching files and exam questions benefit from this image when asking for side-specific landmarks, including the lateral supracondylar ridge as the origin region for brachioradialis and extensor carpi radialis longus and the nearby lateral epicondyle associated with lateral epicondylitis mechanics. It also fits well in surgical anatomy decks for humeral shaft approaches, where consistent naming of margo lateralis, deltoid tuberosity, and distal lateral column reduces ambiguity across texts. Anatomical accuracy verified by SciePro's Medical Advisory Board.