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Pectoralis Minor: Function, Blood Supply & Innervation

Instructor: Dan Washmuth

Dan has taught college Nutrition, Anatomy, Physiology, and Sports Nutrition courses and has a master's degree in Dietetics & Nutrition.

The pectoralis minor is a relatively small but important muscle located in the chest. Read this lesson to learn all kinds of interesting facts about this muscle, including its function, blood supply, and innervation.

Small Muscle of the Chest

When you were a kid, did you ever try to hold your breath under water for as long as you could? Before you went under water, what did you do? You probably took in a big, deep breath, right? This big, deep breath was made possible in part by the pectoralis minor muscle.

The pectoralis minor muscle is a relatively small muscle that is located in each side of the chest, directly under the much larger pectoralis major muscle. Specifically, this muscle begins from the third through fifth ribs and then extends diagonally up the chest and attaches to the scapula (shoulder blade).


The pectoralis minor is a relatively small muscle that runs up diagonally on both sides of the chest.
pectoralis minor


What Does the Pectoralis Minor Do?

The pectoralis minor muscle functions primarily to move the scapula both forward and downward. The scapula is one of the bones that make up the shoulder joint. By moving the scapula forward and downward, the pectoralis minor muscle helps to maintain the mobility of the shoulder joint, which is one of the most mobile joints in the body.

Additionally, the pectoralis minor functions to raise the third through fifth ribs, which can aid in inhalation by helping the rib cage to expand, allowing lung capacity to increase (just like when you took a deep breath before trying to hold your breath underwater).


The pectoralis minor helps to elevate the rib cage when a person takes a deep breath in, just like when you are trying to hold your breath for a long time.
holding breath


Blood Vessel of the Pectoralis Minor

Muscles are very metabolically active tissues, meaning that they required a lot of blood in order to function properly and stay healthy. The blood vessel that supplies the pectoralis minor muscle with blood is the thoracoacromial artery, which is a short artery that branches off the larger axillary artery of the chest and upper extremities.


The pectoralis minor muscle receives its blood supply from the thoracoacromial artery.
arteries

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