Trapezoid Line On The Clavicle, Inferior View

Description

Trapezoid line on the inferior surface of the clavicle occupies the lateral third of the bone, just medial to the acromial end and anterior to the conoid tubercle. From this inferior perspective, the ridge runs obliquely, with its roughened cortical texture contrasting against the smoother adjacent undersurface of the shaft. Medially, the line fades into the flatter inferior clavicular surface, while laterally it approaches the acromial extremity within the shoulder girdle. A small landmark. This region matters because the trapezoid line marks the attachment area for the trapezoid ligament, the anterolateral component of the coracoclavicular ligament complex that suspends the scapula from the clavicle and stabilizes the acromioclavicular joint. Disruption of the coracoclavicular ligaments in higher grade acromioclavicular separations shifts load from ligament to bone, and distal clavicle fractures near the lateral third can behave as unstable patterns when the trapezoid and conoid ligament insertions no longer counteract superior displacement of the medial fragment. By isolating the inferior surface and the bony relief around the conoid tubercle and trapezoid line, the illustration gives a practical map for orienting bone tunnels, suture-button constructs, or hook plate positioning during AC joint and coracoclavicular reconstructions while keeping attention on the correct attachment footprint. Use this illustration in upper limb anatomy and osteology teaching to anchor palpation and labeling of clavicular landmarks beyond the commonly taught conoid tubercle, and in orthopedic or sports medicine publications discussing AC joint injury classification, distal clavicle fracture mechanics, or coracoclavicular ligament reconstruction. It also suits operative technique manuals where a single inferior viewpoint helps readers confirm laterality and implant orientation on the clavicle alone. Anatomical accuracy verified by SciePro's Medical Advisory Board.