Latissimus Dorsi
 
The Latissimus Dorsi lacks direct attachment to the vertebral column. It is attached via aponeurosis to the spinous processes of thoracic (T6-T12), lumbar (L1-L5), and sacral (median crest) vertebrae. Latissimus dorsi attaches directly to the lower 4 ribs and the posterior iliac crest. The thoracodorsal nerve innervates the Latissimus dorsi.

The nerve and vascular supply of the latissimus dorsi come from a discrete neurovascular pedicle in the axilla. This allows the bulk of the muscle and overlying skin to be mobilized as a substitute for the pectoralis major muscle following radical mastectomy for cancer of the breast. The latissimus dorsi muscle is a landmark for the lumbar (Petit's) triangle. It forms the posterior boundary, while the inferior boundary is the iliac crest, and the anterior boundary is the external abdominal oblique. Lumbar triangle hernias are seen in all age groups and are more common in males, arising more frequently on the left side.