Latissimus Dorsi

Muscle Origin

All lumbar vert., sacrum, coccyx and posterior iliac crest to intertubercular sulcus of the humerus.

Spinous processes of thoracic T7-T12, 9th to 12th ribs, the lumbar and sacral vertebrae (via the thoracolumbar fascia), and the posterior third of the external lip of the iliac crest. Occasionally by a slip from the posterior surface of the inferior angle of the scapula.anatomy-model-muscles-back-039-edited

Insertion

Floor of intertubercular groove of the humerus.

The Latissimus Dorsi ends as a flattened tendon in front of the attachment of teres major to the floor of the bicipital groove of the humerus. As the muscle curves around the inferolateral border of teres major, the fiber bundles of latissimus dorsi rotate around each other, so that fibers that originate lowest insert highest on the humerus, and fibers that originate highest insert lowest on the humerus.

Action

Extends, adducts and medially rotates humerus at the shoulder.

The Latissimus Dorsi adducts, extends and internally rotates the arm when the insertion is moved towards the origin. When observing the muscle action of the origin towards the insertion, the lats are a very powerful rotator of the trunk.

Innervation – Nerve control

Thoracodorsal nerve.

The latissimus dorsi is supplied by the sixth, seventh, and eighth cervical nerves through the thoracodorsal (long scapular) nerve. Electromyography suggests that it consists of six groups of muscle fibres that can be independently coordinated by the central nervous system. Wiki

Artery

Thoracodorsal branch of the subscapular artery.

The thoracodorsal artery is a branch of the subscapular artery. It travels inferiorly with the thoracodorsal nerve and supplies the latissimus dorsi. Wiki

Antagonist muscles

Deltoid and trapezius muscle.

Deltoid, Supraspinatus, Infraspinatus, Teres major and minor, Subscapularis.

Pictures of muscles

 

Trigger Point Referrals

 

Stretching description

 

Exercises

 

Injuries

 

Treatment

 

Additional Resources
Wiki
Innerbody

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