Category: Muscles

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Anatomy & Physiology: Muscles—Pectoralis Minor.

Structure.

• Origin: ribs 2-5, ribs 3-5, or ribs 2-4.
• Insertion: coracoid process of scapula.

Function.

• Concentric action: protracts scapula/abduction, depresses scapula, and downward rotation; lateral tilting the scapula at he scapulocostal joint (ScC), upward tilt of scapula at ScC.
• Reverse mover action: elevates ribs 3-5 during forced inhalation when scapula is stabilized.
• Eccentric action: controls/restrains/slows scapular retraction, elevation, upward rotation, medial tilt, and downward tilt; controls/restrains/slows depression of ribs 3-5.
• Isometric action: stabilization of the shoulder girdle, stabilization of scapula, stabilizes ribs 3-5.
• Innervation: medial pectoral nerve.
• Arterial supply: pectoral branches of the thoracoacromial trunk (branch of axillary artery); posterior intercostal arteries (branch of aorta); lateral thoracic artery (branch of axillary artery).

Clinical Significance.

Pectoralis minor. Used with permission by 3D4Medical.

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.

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Anatomy & Physiology: Muscles—Subclavius.

Structure.

• Origin: first rib.
• Insertion: clavicle.

Function.

• Concentric action: depress and move clavicle anteriorly at sternoclavicular joint (SC); protraction of clavicle at SC, downward rotation of clavicle at SC joint; helps stabilize pectoral girdle.
• Reverse mover action: elevate first rib of sternocostal and costospinal joints.
• Eccentric action: controls/restrains/slows clavicular retraction, elevation, upward rotation, and controls/restrains/slows depression of first rib.
• Isometric action: stabilization of the scapula. Stabilization of clavicle and first rib.
• Innervation: subclavian nerve.
• Arterial supply: clavicular branch of thoracoacromial trunk (branch of axillary artery), suprascapular artery (branch of thyrocervical trunk).

Clinical Significance.

Subclavius. Used with permission by 3D4Medical.

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.