Subscapularis muscle

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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)
Action:	rotates medially humerus; stabilizes shoulder
Dorlands /Elsevier	m_22/12551017

The Subscapularis is a large triangular muscle which fills the subscapular fossa.

Contents 1 Origin and insertion 2 Relations 3 Innervation 4 Actions 5 Additional images 6 References 7 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] 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 As such, some of the information contained herein may be outdated. Please edit the article if this is the case, and feel free to remove this notice when it is no longer relevant.

v • d • e List of muscles of upper limbs VERTEBRAL COLUMN trapezius - latissimus dorsi - rhomboid (major, minor) - levator scapulae THORACIC WALLS pectoralis major - pectoralis minor - subclavius - serratus anterior SHOULDER deltoid - rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis) - teres major ARM anterior compartment: coracobrachialis - biceps brachii - brachialis posterior compartment: triceps brachii - anconeus FOREARM anterior compartment: superf. - pronator teres - palmaris longus - flexor carpi radialis - flexor carpi ulnaris - flexor digitorum superficialis anterior compartment: deep - pronator quadratus - flexor digitorum profundus - flexor pollicis longus posterior compartment: superf. - mobile wad (brachioradialis, extensor carpi radialis longus and brevis) - extensor digitorum, - extensor digiti minimi - extensor carpi ulnaris posterior compartment: deep - supinator - anatomical snuff box (abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus) - extensor indicis 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)