Latissimus dorsi

Latissimus Dorsi

The Latissimus Dorsi (commonly referred to as the "lats") is a large, flat muscle on the back that stretches to the sides, behind the arm, and is partly covered by the trapezius on the back near the midline.

Anatomy

The latissimus dorsi originates from the inferior thoracic and lumbar vertebrae, sacrum, iliac crest, and the four lowermost ribs. It inserts on the floor of the intertubercular groove of the humerus. Its main functions are to adduct, extend and internally rotate the arm. It has a synergistic role in extension and lateral flexion of the lumbar spine.

Function

The latissimus dorsi is responsible for extension, adduction, horizontal abduction, flexion from an extended position, and (medial) internal rotation of the shoulder joint. It also has a synergistic role in extension and lateral flexion of the lumbar spine.

Clinical significance

Due to its versatility in function, the latissimus dorsi is often used in surgical procedures such as breast reconstruction surgery after mastectomy, or to repair a rotator cuff tear.

Training

Exercises that target the latissimus dorsi include pull-ups, chin-ups, and lat pulldowns. In bodybuilding, this muscle is developed to give the back a wide and powerful appearance.

See also

• Muscular system
• Human anatomy
• Trapezius muscle
• Breast reconstruction