Subscapularis Muscle

Origin

The subscapularis muscle originates from the:

- subscapular fossa of scapula;

- aponeurosis that surrounds the muscle.

Insertion

The fibers of the subscapularis muscle travel superolaterally and insert, via a broad tendon, onto the lesser tubercle of the humerus. Part of this tendon also merges with the capsule of the glenohumeral (shoulder) joint.

Key Features & Anatomical Relations

The subscapularis muscle is one of the rotator cuff muscles. It is a thick, multipennate type of skeletal muscle. It is located:

- anterior (deep) to the scapula, the glenohumeral (shoulder) joint, and the subtendinous bursa of subscapularis muscle;

- posterior to the serratus anterior and teres minor muscles, and the axillary artery and vein;

- superior to the teres major and latissimus dorsi muscles;

- lateral to the rhomboid major and minor muscles.

The subscapularis muscle contributes to the formation of the posterior wall of the axilla.

Actions

The subscapularis muscle medially rotates the arm at the glenohumeral (shoulder) joint. It is one of the four rotator cuff (SITS) muscles, the other three being the supraspinatus, infraspinatus, and teres minor muscles. These muscles work together to stabilize the glenohumeral joint, by holding the head of the humerus in the glenoid fossa of the scapula, during its movements (Standring, 2016).

List of Clinical Correlates

- Injury or rupture of rotator cuff

References

Standring, S. (2016) Gray's Anatomy: The Anatomical Basis of Clinical Practice. Gray's Anatomy Series 41st edn.: Elsevier Limited.

Actions

The subscapularis muscle medially rotates the arm at the glenohumeral (shoulder) joint. It is one of the four rotator cuff (SITS) muscles, the other three being the supraspinatus, infraspinatus, and teres minor muscles. These muscles work together to stabilize the glenohumeral joint, by holding the head of the humerus in the glenoid fossa of the scapula, during its movements (Standring, 2016).