All About Pectoralis Minor Muscle/Pectoralis minor is a thin triangular muscle situated at the upper part of the chest, beneath the pectoralis major in the human body. It arises from the upper margins and outer surfaces of the third, fourth, and fifth ribs, near their cartilages and from the aponeuroses covering the intercostalis. The fibers pass superior and lateral and converge to form a flat tendon, which is inserted into the medial border and upper surface of the coracoid process of the scapula.
Pectoralis minor tightness may be seen in individuals with scapular dyskinesis, and stretching is used for the treatment of altered scapular motion in sports and clinical fields. However, few researchers have reported on the effects of pectoralis minor stiffness on scapular motion during arm elevation. This study investigated whether an acute decrease of pectoralis minor stiffness after stretching changes the scapular motion during arm elevation. The study allocated 15 dominant and 15 nondominant upper limbs in healthy men as control and interventional limbs, respectively. In the intervention limb group, the shoulder was passively and horizontally abducted at 150° of elevation for 5 minutes to stretch the pectoralis minor muscle. Before and after stretching, an electromagnetic sensor was used to examine 3-dimensional scapular motion during abduction and scaption. Ultrasonic shear wave elastography was used to measure pectoralis minor stiffness before and immediately after stretching and after arm elevation.
Anatomy of Pectoralis Minor
The pectoralis minor lies underneath its larger counterpart muscle, pectoralis major. Both of these muscles form part of the anterior wall of the axilla region.
- Attachments – Originates from the 3rd-5th ribs, and inserts into the coracoid process of the scapula.
- Function – Stabilises the scapula by drawing it anteroinferior against the thoracic wall.
- Innervation – Medial pectoral nerve.
The Function of Pectoralis Minor
The pectoralis minor depresses the point of the shoulder, drawing the scapula superior, towards the thorax, and throwing its inferior angle posteriorly.
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).
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.
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