Subscapularis muscle
Deep muscles of the chest and front of the arm, with the boundaries of the axilla. (Subscapularis visible near center top.)
Latin	musculus subscapularis
Gray's	subject #123 440
Origin	subscapular fossa
Insertion	lesser tubercle of humerus
Artery	transverse cervical artery, [1] subscapular artery
Nerve	upper subscapular nerve, lower subscapular nerve (C5, C6)
Actions	rotates medially humerus; stabilizes shoulder

The Subscapularis is a large triangular muscle which fills the subscapular fossa and inserts into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.

Contents 1 Origin and insertion 2 Relations 3 Innervation 4 Actions 5 Injury diagnosis 6 Additional images 7 References 8 External links

[edit] Origin and insertion

It arises from its medial two-thirds and from the lower two-thirds of the groove on the axillary border(subscapular fossa) of the scapula.

Some fibers arise from tendinous laminæ which intersect the muscle and are attached to ridges on the bone; others from an aponeurosis, which separates the muscle from the Teres major and the long head of the Triceps brachii.

The fibers pass lateralward, and, gradually converging, end in a tendon which is inserted into the lesser tubercle of the humerus and the front of the capsule of the shoulder-joint.

[edit] Relations

The tendon of the muscle is separated from the neck of the scapula by a large bursa, which communicates with the cavity of the shoulder-joint through an aperture in the capsule.

[edit] Innervation

Innervation to subscapularis is supplied by the upper and lower subscapular nerves, branches of the posterior cord of the brachial plexus.

[edit] Actions

The Subscapularis rotates the head of the humerus medially (internal rotation); when the arm is raised, it draws the humerus forward and downward. It is a powerful defense to the front of the shoulder-joint, preventing displacement of the head of the humerus.

[edit] Injury diagnosis

The Bear Hug test (internal rotation while palm is held on opposite shoulder and elbow is held in a position of maximal anterior translation) for Subscapularis muscle tears has high sensitivity. Positive Bear-Hug and Belly Press tests indicate significant tearing of subscapularis.[1]

[edit] Additional images

Diagram of the human shoulder joint

Left scapula. Costal surface.

Left humerus. Anterior view.

The axillary artery and its branches.

[edit] References

[edit] External links

• LUC subs
• Subscapularis+muscle at eMedicine Dictionary

This article was originally based on an entry from a public domain edition of Gray's Anatomy. As such, some of the information contained within it may be outdated.

v • d • e List of muscles of upper limbs (TA A04.6, GA 4.432) Shoulder deltoid · rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) · teres major fascia: Deltoid fascia · Supraspinous fascia · Infraspinous fascia Arm (compartments) Anterior coracobrachialis · biceps brachii · brachialis Posterior triceps brachii · anconeus · Articularis cubiti Fascia Axillary sheath · Axillary fascia · Brachial fascia · intermuscular septa (Lateral, Medial) Other spaces (Quadrangular space, Triangular space, Triangular interval) Forearm Anterior superficial: pronator teres · palmaris longus · flexor carpi radialis · flexor carpi ulnaris · flexor digitorum superficialis deep: pronator quadratus · flexor digitorum profundus · flexor pollicis longus Posterior superficial: mobile wad (brachioradialis, extensor carpi radialis longus and brevis) · extensor digitorum · extensor digiti minimi · extensor carpi ulnaris deep: supinator · anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) · extensor indicis Fascia Bicipital aponeurosis · common tendons (Extensor, Flexor) · Antebrachial fascia Other Cubital tunnel Hand Lateral volar thenar (opponens pollicis, flexor pollicis brevis, abductor pollicis brevis) · adductor pollicis Medial volar hypothenar (opponens digiti minimi, flexor digiti minimi brevis, abductor minimi digiti) · palmaris brevis Intermediate lumbrical · interossei (dorsal, palmar) Fascia posterior: Extensor retinaculum · Extensor expansion anterior: Flexor retinaculum · Palmar aponeurosis

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