Pectoral muscle

Pectoral Muscle

The pectoral muscles are a group of muscles located on the chest of the human body. These muscles are primarily responsible for the movement of the shoulder joint. The pectoral muscles are divided into two main parts: the pectoralis major and the pectoralis minor.

Pectoralis Major

The pectoralis major is a thick, fan-shaped muscle situated at the chest (anterior) of the human body. It makes up the bulk of the chest muscles and lies under the breast. The pectoralis major has two parts: the clavicular head and the sternal head.

• Clavicular Head: This part originates from the anterior surface of the medial half of the clavicle.
• Sternal Head: This part originates from the anterior surface of the sternum, the superior six costal cartilages, and the aponeurosis of the external oblique muscle.

The pectoralis major is responsible for movements such as flexion, adduction, and medial rotation of the humerus.

Pectoralis Minor

The pectoralis minor is a thin, triangular muscle located beneath the pectoralis major. It originates from the third to fifth ribs, near their costal cartilages, and inserts into the medial border and superior surface of the coracoid process of the scapula.

The pectoralis minor stabilizes the scapula by drawing it inferiorly and anteriorly against the thoracic wall. It is also involved in movements such as protraction and depression of the scapula.

Function

The pectoral muscles play a crucial role in the movement and stabilization of the shoulder joint. They are involved in various actions such as pushing, lifting, and rotating the arm. These muscles are also important for maintaining posture and supporting the upper body.

Clinical Significance

Injuries to the pectoral muscles, such as strains or tears, can occur due to overuse or trauma. These injuries are common in athletes who engage in activities that involve repetitive shoulder movements, such as weightlifting or throwing sports. Symptoms of a pectoral muscle injury may include pain, swelling, and limited range of motion in the shoulder.

See Also

• Muscle
• Shoulder joint
• Anatomy

References

• Pectoralis Major Muscle Anatomy
• Pectoralis Minor Muscle Anatomy

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