Latissimus dorsi

Musculus latissimus dorsi

The broadest muscle of the back, forming part of the posterior axillary fold. It originates from the spinous processes of T7-T12, thoracolumbar fascia, iliac crest, and lower three ribs. It inserts on the floor of the intertubercular sulcus of the humerus.

Type Muscle
Body System Muscular
Body Region Back
Latin Name Musculus latissimus dorsi
FMA ID 13357

Function

Extends, adducts, and medially rotates the arm at the shoulder. A powerful climbing muscle. Also assists in forced expiration (coughing, sneezing) and trunk lateral flexion.

Clinical Significance

The latissimus dorsi is used in breast reconstruction and thoracic wall reconstruction. It is the main muscle used in swimming and rowing, susceptible to strain injuries. Thoracodorsal nerve injury causes weakness of arm adduction.

Frequently Asked Questions

What is the latissimus dorsi?
The latissimus dorsi is the broadest muscle of the back, forming a large, flat sheet that contributes to the posterior axillary fold. It is one of the prime movers of the upper limb, particularly for adduction and medial rotation at the shoulder.
Where is the latissimus dorsi located?
The latissimus dorsi originates from the spinous processes of T7–T12, the thoracolumbar fascia, the iliac crest, and the lower three ribs. Its fibers converge to insert on the floor of the intertubercular (bicipital) sulcus of the humerus.
What is the function of the latissimus dorsi?
The latissimus dorsi extends, adducts, and medially rotates the arm at the shoulder joint. It is particularly important in pulling movements such as climbing, swimming, and rowing, and also assists in respiration during forced expiration.
What conditions may be associated with the latissimus dorsi?
The latissimus dorsi may be involved in muscle strains from overhead or pulling activities, and is occasionally a site of referred pain in shoulder and back disorders. It is also used as a donor flap in reconstructive surgeries, such as after mastectomy.
What does the latissimus dorsi look like?
The latissimus dorsi is a broad, flat, fan-shaped muscle that forms the lower part of the back and the posterior axillary wall. On imaging, it is identifiable as a wide, thin muscular sheet covering the lower thoracic and lumbar regions.

Related Structures

anterior internodal tract anterior internodal fasciculus aponeurosis aponeuroses atrioventricular node A-V node Bachmann's bundle anterior interatrial band Biceps brachii Musculus biceps brachii bundle of His A-V bundle cardiac muscle tissue of myocardium cardiac Purkinje fiber cardiac Purkinje fiber

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Educational Disclaimer

This content is for educational and informational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider for medical decisions.

Data sources: Terminologia Anatomica, Foundational Model of Anatomy, Wikidata.