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Muscles: Latissimus Dorsi.

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Anatomy & Physiology: Muscles—Latissimus Dorsi.

Structure.

  • Origin: spinous processes of T7-T12; lumbar vertebrae; iliac and sacral crests; thoracolumbar fascia; ribs 9-12.
  • Insertion: inferior angle of scapula; intertubecular groove of humerus.

Function.

  • Concentric action: shoulder extension, adduction, and internal/medial rotation; draws arm inferiorly and posteriorly; scapular depression.
  • Reverse mover action: contralateral rotation of the pelvis and trunk at spinal joints. Ipsilateral elevation of pelvis at lumbosacral joint. Anterior tilt of pelvis. Trunk elevation.
  • Eccentric action: shoulder flexion, abduction, external rotation and spinal flexion. Controls/restrains/slows lateral rotation, abduction, and flexion of arm. Controls/restrains/slows ipsilateral rotation, ipsilateral depression, posterior tilt of pelvis. Controls/restrains/slows ipsilateral rotation, flexion, and depression of trunk. Controls/restrains/slows scapula.
  • Isometric action: stabilization of the lumbo-pelvic hip complex and shoulder. Stabilizes spinal joints.
  • Innervation: thoracodorsal nerves.
  • Arterial supply: thoracodorsal artery (branch of subscapular artery); dorsal branches of posterior intercostal arteries (branches of aorta).

Clinical Significance.

More.

References

Biel, A. (2015). Trail guide to the body: A hands-on guide to locating muscles, bones and more.

Cedars-Sinai. (2018). Vertebrae of the spine. Retrieved from https://www.cedars-sinai.org/health-library/diseases-and-conditions/v/vertebrae-of-the-spine.html

Clark, M., Lucett, S., Sutton, B. G., & National Academy of Sports Medicine. (2014). NASM essentials of corrective exercise training. Burlington, MA: Jones & Bartlett Learning.

Jenkins, G., & Tortora, G. J. (2012). Anatomy and Physiology: From Science to Life, 3rd Edition International Stu. John Wiley & Sons.

Muscolino, J. E. (2017). The muscular system manual: The skeletal muscles of the human body.