Subscapularis muscle

MRI. Partial rupture of the cranial subscapularis tendon at the insertion site.

Subscapularis muscle animation3

Subscapularis muscle animation

Thorax section 9

Shoulder joint

The subscapularis muscle is a large triangular muscle that fills the subscapular fossa of the scapula. It is one of the four muscles that make up the rotator cuff of the shoulder.

Anatomy

The subscapularis muscle originates from the subscapular fossa, which is the concave surface on the anterior side of the scapula. It inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder joint.

Innervation

The subscapularis muscle is innervated by the upper subscapular nerve and the lower subscapular nerve, both of which are branches of the posterior cord of the brachial plexus.

Blood Supply

The blood supply to the subscapularis muscle is primarily provided by the subscapular artery, a branch of the axillary artery.

Function

The primary function of the subscapularis muscle is to medially rotate the humerus. It also plays a role in the adduction of the arm and helps stabilize the shoulder joint by holding the head of the humerus in the glenoid cavity.

Clinical Significance

Injuries to the subscapularis muscle can result in pain and weakness in the shoulder, particularly during activities that involve internal rotation of the arm. Tears of the subscapularis tendon are less common than other rotator cuff injuries but can occur, especially in athletes and individuals who perform repetitive overhead activities.

See Also

• Rotator cuff
• Shoulder joint
• Scapula
• Humerus
• Brachial plexus

Related Pages

• Infraspinatus muscle
• Teres minor muscle
• Supraspinatus muscle
• Subscapular artery
• Upper subscapular nerve
• Lower subscapular nerve