Latissimus Dorsi · What Is It, Location, Function, and More

Published: Feb 04, 2025

Author: Lily Guo•

Editor: Alyssa Haag•

Editor: Ian Mannarino, MD•

Editor: Kelsey LaFayette, DNP, ARNP, FNP-C

Illustrator: Jessica Reynolds, MS•

Copyeditor: Stacy Johnson, LMSW

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What is the latissimus dorsi muscle?

The latissimus dorsi muscle, commonly known colloquially as the ‘lats,’ is one of the largest muscles of the back, stretching across the lower posterior thorax. Its primary function is in upper extremity movement. However, it also serves as a respiratory accessory muscle. The muscle is innervated by the thoracodorsal nerve, originating from the posterior cord of the brachial plexus (i.e., C6-8). Blood flow to the latissimus dorsi stems from the thoracodorsal branch of the subscapular artery, a branch of the axillary artery.

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Where is the latissimus dorsi located?

The latissimus dorsi is located in the lower posterior thorax. The uppermost fibers of the latissimus dorsi are oriented horizontally, while the lower fibers are oriented more vertically. The muscle originates from several locations, including the spinous processes of vertebrae T7-L5, the thoracolumbar fascia, posterior iliac crest, lower third or fourth ribs, and the inferior angle of the scapula. The muscle fibers then extend towards the axilla, wrapping around the teres major (i.e., a muscle located in the back that runs along the lateral border of the scapula), to insert on the floor of the intertubercular sulcus of the humerus.

What does the latissimus dorsi muscle do?

The latissimus dorsi muscle works with the teres major and the pectoralis major muscles to depress the arm and adduct, extend, and internally rotate the shoulder at the glenohumeral joint (i.e., shoulder joint). The latissimus dorsi muscle also functions to pull the thorax/trunk upwards and forwards by rotating the scapula downward. This occurs when the upper limbs, such as when climbing or performing a pull-up, are extended overhead. The latissimus dorsi further plays a role in the extension and lateral flexion of the lumbar spine. It is also active during deep inspiration and with forceful respiratory functions, such as coughing and sneezing.

Can the latissimus dorsi muscle be injured?

The latissimus dorsi muscle can be injured due to overuse, poor posture, or poor form in sports and exercise. Common exercises that engage the latissimus dorsi include weightlifting, pull-ups, and bench-presses. Specific sports that can increase the risk of latissimus dorsi muscle injury include golf, baseball, skiing, rowing, tennis, and swimming. If it is injured, an individual may feel pain across their entire back, shoulders, and scapula. In some cases, the pain may radiate to the inside of the upper arms and down to the fingers.

The clinician may use the manual muscle test to diagnose an injured muscle when the individual lies on their stomach with the injured arm lifted toward the ceiling. The clinician then applies downward pressure on the arm. If the latissimus dorsi is injured, the person will not be able to hold this position or resist force. Treatment of an injured latissimus dorsi muscle includes rest – typically as part of the RICE regimen, which is an acronym for Rest, Ice, Compress, and Elevate. The clinician may also suggest taking non-steroidal anti-inflammatory medication (e.g., NSAIDs) if the pain or swelling is severe.

What are the most important facts to know about the latissimus dorsi muscle?

The latissimus dorsi muscle is a large flat muscle in the lower thorax. Its origin is mainly from the vertebral processes of spinal levels T7-L5, and it inserts at the humerus to adduct, extend, and internally rotate the shoulder and arm. It also plays a role in the extension and flexion of the lumbar spine and in respiratory functions such as coughing and sneezing. The latissimus dorsi can be injured during exercise, specifically when performing pull-ups and bench-presses. Sports injuries, particularly in golf, baseball, or swimming, can cause latissimus dorsi muscle injury. The pain is often located across the back and can radiate to the arms and fingers. Diagnosis includes a manual muscle test, and treatment involves the RICE protocol and NSAID use.

References

Donohue, Benjamin; Lubitz, Marc (December 20, 2016). "Sports Injuries to the Latissimus Dorsi and Teres Major." The American Journal of Sports Medicine. 45 (10): 2428–2435. doi:10.1177/0363546516676062

Ernstbrunner, L., Jessen, M., Rohner, M., et al. (2021)Anatomical study of the teres major muscle: description of an additional distal muscle slip. BMC Musculoskelet Disord 22, 359. https://doi.org/10.1186/s12891-021-04227-3

Friedman, M.V., Stensby, J.D., Hillen, T.J., Demertzis, J.L., Keener, J.D. Traumatic tear of the Latissimus Dorsi Myotendinous Junction: Case Report of a CrossFit-Related Injury. Sports Health. 2015;7(6):548-552. doi:10.1177/1941738115595975

Henson, B., Kadiyala, B., Edens, M.A. StatPearls [Internet]. StatPearls Publishing; Treasure Island (FL): Aug 10, 2021. Anatomy, Back, Muscles.

Jeno, S.H., Varacallo, M. Anatomy, Back, Latissimus Dorsi. [Updated 2021 Aug 11]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK448120/