Latissimus Dorsi, Lateral View

Description

Running in a lateral profile from the posterior axillary fold to the lower back, the latissimus dorsi blankets the posterolateral thoracic wall and narrows superiorly toward its tendon on the proximal humerus. Its inferior fibers broaden into a thin aponeurosis that blends with the thoracolumbar fascia over the lumbar vertebrae and posterior iliac crest, lying posterior to the ribs and lateral to the spinous processes. The muscle passes inferior to the scapula, contributing to the contour of the flank and forming the posterior boundary of the axilla, with the humerus positioned anterior and lateral to the thorax. Bony landmarks such as the ribs, scapula, clavicle, vertebral column, and pelvis provide clear attachment context. A true lateral view clarifies how latissimus dorsi wraps from midline posterior attachments to an anterior humeral insertion, explaining its combined actions of shoulder extension, adduction, and internal rotation. This relationship matters in axillary surgery because the latissimus forms the posterior axillary fold and overlies the plane used for exposure of the axillary vessels and brachial plexus in some approaches. It also frames common reconstructive and sports medicine discussions, from latissimus dorsi tendon transfer for irreparable rotator cuff tears to harvesting a latissimus dorsi myocutaneous flap based on the thoracodorsal vessels. A dependable landmark. Ideal for musculoskeletal anatomy lectures on the back and shoulder, surgical atlases covering axillary dissection and thoracodorsal pedicle anatomy, and patient education materials explaining tendon transfer or flap reconstruction. Rehabilitation texts can also pair this view with biomechanics of pulling, climbing, and swimming to connect form to function. Anatomical accuracy verified by SciePro's Medical Advisory Board.