Latissimus dorsi | ARM MOVERS

The latissimus dorsi 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.

ORIGIN:

The latissimus dorsi originates via lumbodorsal fascia into spines of T7-L5, lower 4 ribs & iliac crest.

INSERTION:

The latissimus dorsi is inserted at the floor of the intertubercular groove of the humerus.

ACTION:

1. the agonist of arm extension.
2. powerful arm adductor.
3. medially rotates arm & shoulder.
4. depresses scapula.
5. pulls the body upward & forward with arms fixed overhead.

NERVE SUPPLY:

The latissimus dorsi is innervated by the sixth, seventh, and eighth cervical nerves through the thoracodorsal (long scapular) nerve.