Latissimus dorsi muscle

Latissimus Dorsi Muscle

The Latissimus Dorsi muscle, shown in red.

The Latissimus Dorsi muscle is one of the largest muscles in the human body. It is a broad, flat muscle located in 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 lower part of the back, where it spans the lumbar and lower thoracic vertebrae, the lower three ribs, the iliac crest, and the inferior angle of the scapula. It inserts on the humerus, contributing to the movement of the shoulder joint.

Function

The Latissimus Dorsi muscle 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

Damage or injury to the Latissimus Dorsi can result in a condition known as "winged scapula", where the scapula protrudes from the back in an abnormal position. This can lead to difficulties in performing movements that involve pulling or lifting.

See Also

• Muscular system
• Human anatomy
• Trapezius muscle
• Rhomboid muscles