Latissimus Dorsi, Gross Anatomy, Posterior View

Description

Prominent across the posterior trunk, the latissimus dorsi (highlighted) fans superolaterally from the thoracolumbar fascia and iliac crest region toward the axilla, where its fibers converge into a thick tendon that wraps around the inferomedial border of the teres major before inserting into the floor of the intertubercular sulcus (bicipital groove) of the humerus. Superiorly, the trapezius spans from the nuchal region to the scapular spine, while the deltoid caps the shoulder laterally and the triceps brachii occupies the posterior arm. Along the midline, the erector spinae columns sit deep and medial to the latissimus dorsi, and inferiorly the gluteus maximus and hamstrings form the posterior hip and thigh contours. Orientation is classic posterior anatomy. For shoulder mechanics, this is the insertion that matters, because the latissimus dorsi’s humeral attachment, after its characteristic anterior twist, drives extension, adduction, and internal rotation at the glenohumeral joint and contributes to depression of the scapular girdle during climbing or crutch walking. The relationship of the tendon to the posterior axillary fold provides a clean surface landmark for the thoracodorsal neurovascular bundle (thoracodorsal nerve and vessels) on the deep surface of the muscle. Surgeons care about that plane. It is also the same anatomy mobilized in a latissimus dorsi myocutaneous flap for breast and chest wall reconstruction, where preserving the thoracodorsal pedicle and understanding the humeral insertion can prevent functional loss and unwanted axillary bulk. In teaching, the posterior female torso format works well for gross anatomy labs, kinesiology modules on shoulder adduction and extension, and exam figures that test recognition of the posterior axillary fold and the bicipital groove insertion. Editorially, it fits atlases, operative manuals discussing pedicled flap harvest, and rehabilitation handouts after tendon transfer or shoulder stabilization procedures. Anatomical accuracy verified by SciePro's Medical Advisory Board.