Upper limb
Pectoralis Major, Sternocostal Head
Musculus pectoralis major (pars sternocostalis)
- Origin
- Sternum and costal cartilage of ribs 2-6
- Insertion
- Crest of the greater tubercle of the humerus, together with the other heads
- Function
- Adduction and internal rotation of the arm; the main depressor of a raised arm
- Innervation
- Medial and lateral pectoral nerves, C7-T1
- Movement & chain
- The largest and most powerful head of the pectoralis major; crucial in pushing and climbing movements where the arm is drawn from above downward.
- Palpation
- Large muscle bulk easily palpated over the sternum and ribs II–VI; forms the major part of the anterior axillary fold.
- Clinical
- Most common site of pectoralis major tendon rupture during heavy bench pressing; requires anatomic surgical repair to restore strength.
- Segmental innervation
- Myotome C7-T1.
- In clinical practice
- Wound management post-laparotomy/chest drain and abdominal wall monitoring; support incision site during coughing to prevent wound dehiscence.
- Region in the model
- Upper limb