1.4 Intrinsic Muscle of the Scapula and Shoulder: Medial Muscle of the Scapula

Medial Muscle of the Scapula

Subscapularis

Teres major

Coracobrachialis

name the medial muscles of the scapula and shoulder (3)

Subscapularis

• large muscle originating from the subscapular fossa

• it crosses the shoulder joint and inserts on the lesser tubercle of humerus

• it serves as the shoulder’s medial collateral ligament.

• Origin: subscapular fossa

• Insertion: lesser tubercle of the humerus

• Action: to adduct, extend, and stabilize the shoulder joint

• Innervation: Subscapular nerve and Axillary nerve

Teres major 

• directly caudal to the subscapularis, belies its descriptive name because it is not round but has three surface

• Origin: arises from the caudal border of the scapula

• Insertion: inserts with the latissimus dorsi muscle on the medial side of the humerus (teres major tuberosity)

• Action:  to flex the shoulder

• Innervation: Axillary nerve

Coracobrachialis

• crosses the medial surface of the shoulder obliquely

• a small spindle-shaped muscle that arises from the coracoid process of the scapula by a relatively long tendon that courses caudodistally across the lesser tubercle

• Origin: coracoid process of the scapula

• Insertion: crest of the lesser tubercle

• Action: to adduct, extend, and stabilize the shoulder joint

• Innervation: Musculocutaneous nerve