Pectoralis Major

Pectoralis Major

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The Pectoralis Major: Anatomy and Function

The Pectoralis Major muscle is a large, fan-shaped muscle located on the anterior wall of the chest. It is composed of two portions, the sternal head and the clavicular head.

Attachments: The Pectoralis Major's clavicular head originates from the anterior section of the medial clavicle. Meanwhile, the sternal head is attached to the front of the sternum, the top six costal cartilages, and the aponeurosis of the external oblique muscle. This muscle's distal attachment goes to the intertubercular sulcus of the humerus.

Function: The Pectoralis Major muscle is responsible primarily for adduction and medial rotation of the upper limb.

Innervation: In terms of nervous supply, the Pectoralis Major is primarily innervated by the lateral and medial pectoral nerves.

Blood Supply: The muscle receives its blood supply via the thoracoacromial artery, specifically the pectoral branch, the superior thoracic artery, and the lateral thoracic artery.

Pectoralis Major Injury

Injury to the Pectoralis Major is relatively more common than injury to other chest muscles. Injury of this muscle often results from significant direct trauma or a sudden force on the shoulder, such as the snatch in weightlifting or bench pressing with too much weight. It can also be caused by overuse or repetitive trauma.

Symptoms of Pectoralis Major injury vary depending on the severity of the injury. Pain is usually the most common symptom, with some people reporting a feeling of instability. Swelling, reddening, and bruise-like discoloration of the chest area may also be observed. In more serious cases, the arm may be weakened, and the elbow may lose its range of motion.

Diagnosis of Pectoralis Major injury is usually done through physical examinations, imaging studies and other diagnostic tests. Ultrasound or MRI may be used to detect muscle tear. Other tests, such as electromyography (EMG) or a nerve conduction study (NCS) may also be used to check the integrity of the nerves.

Treatment options for Pectoralis Major Injury depend on the severity of the injury. Rest, ice, and analgesics can provide relief to minor injuries. Physical therapy is usually recommended for a complete recovery from muscle tears, as it helps to strengthen the affected area. Surgery may also be recommended in more severe cases, to repair the muscle or to relieve the pressure on the nerves.


The Pectoralis Major is a key muscle of the anterior chest wall. It is responsible for adduction and medial rotation of the upper limb, and it is innervated by the lateral and medial pectoral nerves. Injury to this muscle is relatively common, and can be caused by direct trauma, overuse, or repetitive trauma. Treatment options vary depending on the severity of the injury, but can include rest, ice, analgesics, physical therapy, or even surgery. It is important to seek medical attention in order to properly diagnose and treat Pectoralis Major Injury.

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