Latissimus Dorsi

Description

Spanning the posterior thorax and lumbar region, the latissimus dorsi is presented as a broad, superficial sheet overlying the thoracolumbar fascia and the lower ribs, with its fibers sweeping superolaterally toward the posterior axillary fold. Medially, the muscle approaches the spinous processes of the lower thoracic vertebrae and the posterior iliac crest; laterally, it converges to a narrow tendon that twists around the teres major before inserting on the floor of the intertubercular sulcus (bicipital groove) of the proximal humerus. The scapulae sit superior and lateral to the muscle belly, and the vertebral column remains the midline skeletal reference from cervical to sacral levels. Posterior landmarks are clear. A posterior view like this matters because latissimus dorsi is both a powerful shoulder extensor and an important surgical donor. Its vascular pedicle (thoracodorsal artery and vein) and motor supply (thoracodorsal nerve, C6 to C8) enter the muscle on its deep anterior surface near the axilla, a relationship surgeons rely on during latissimus dorsi myocutaneous flap harvest for breast reconstruction or chest wall coverage. Tendon orientation also explains clinical findings: pain at the posterior axillary fold after overhead pulling or climbing can reflect a proximal latissimus tear, and the twisted insertion helps account for internal rotation strength even when the scapula is fixed. Use this artwork in gross anatomy and kinesiology teaching to connect thoracolumbar fascia, iliac crest, ribs, scapular position, and humeral insertion to specific shoulder actions, or in surgical education materials describing thoracodorsal pedicle dissection and flap design. It also supports orthopedic and sports medicine texts discussing proximal tendon injury patterns and rehabilitation targets for shoulder extension and adduction. Anatomical accuracy verified by SciePro's Medical Advisory Board.