Pectoralis Major Muscle
Pectoralis Major Clavicular Head
Origin: Anterior surface of the medial half of the clavicle
Insertion: Lateral lip of the bicipital groove of the humerus and the anterior lip of the deltoid tuberosity
Actions: Flexion, adduction, internal rotation of the arm at the shoulder
Innervation: Medial pectoral nerve (C8, T1) and lateral pectoral nerve (C5, 6, 7 )
Blood Supply: Pectoral branches from the thoraco-acromial artery
Primary Actions of the Pectoralis Major-Clavicular Head
1. Flexion of the arm at the shoulder
Agonists:
- Deltoid (anterior part)
- Biceps Brachii
- Coracobrachialis
Antagonists:
- Deltoid (posterior fibers)
- Triceps Brachii (long head)
- Latissimus Dorsi
- Pectoralis Major (sternal head)
- Teres Major
2. Adduction of the arm at the shoulder
Agonists:
- Latissimus Dorsi
- Teres Major
- Pectoralis Major (sternal head)
- Triceps Brachii
Antagonists:
- Deltoid (middle fibers)
- Supraspinatus
Coracobrachialis and teres minor assist with adduction of the arm at the shoulder.
3. Internal rotation of the arm at the shoulder
Agonists:
- Latissimus Dorsi
- Subscapularis
- Deltoid (anterior fibers)
- Pectoralis Major (sternal head)
- Teres Major
Antagonists:
- Infraspinatus
- Teres Minor
- Deltoid (posterior part)
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Pectoralis Major Sternal Head
Origin: Lateral aspects of the manubrium and body of the sternum, the upper six costal cartilages and the aponeurosis of external abdominal oblique
Insertion: Lateral lip of the bicipital groove of the humerus and anterior lip of the deltoid tuberosity
Actions: Adduction, internal rotation and extension of the arm at the shoulder
Innervation: Medial pectoral nerve (C8, T1) and lateral pectoral nerve (C5, 6, 7 )
Blood Supply: Pectoral branches from the thoraco-acromial artery
Primary Actions of the Pectoralis Major-Sternal Head
1. Adduction of the arm at the shoulder
Agonists:
- Latissimus dorsi
- Teres major
- Pectoralis major (clavicular head)
- Triceps brachii (long head)
Antagonists:
- Deltoid (middle)
- Supraspinatus
Coracobrachialis and teres minor assist with adduction of the arm at the shoulder.
2. Internal rotation of the arm at the shoulder
Agonists:
- Latissimus dorsi
- Subscapularis
- Deltoid (anterior)
- Pectoralis major (clavicular head)
- Teres major
Antagonists:
- Infraspinatus
- Teres minor
- Deltoid (posterior part)
3. Extension of the arm at the shoulder
Agonists:
- Latissimus dorsi
- Deltoid (posterior)
- Triceps brachii (long head)
- Teres major
Antagonist:
- Deltoid (anterior part)
- Biceps brachii
- Coracobrachialis
- Pectoralis major (clavicular head)
Muscle Pain Information: The pectoralis major muscle contributes to pain in the chest, shoulder, breast and upper back.
An excellent book for those beginning the study of anatomy. Coloring helps memory retention.
For intermediary anatomy students learning skeletal and muscle structure.
For beginning and intermediary anatomy . Muscle overlays on the human body. Excellent visuals!