Subscapularis muscle

From Wikipedia, the free encyclopedia

Subscapularis muscle
Image:Gray411.png
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:	humerus
Blood:	subscapular artery
Nerve:	subscapular nerves
Action:	rotates humerus medially; stabilizes shoulder
Dorlands/Elsevier	m_22/12551017

The Subscapularis is a large triangular muscle which fills the subscapular fossa, and arises from its medial two-thirds and from the lower two-thirds of the groove on the axillary border of the bone.

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.

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] Nerves

The Subscapularis is supplied by the fifth and sixth cervical nerves through the upper and lower subscapular nerves.

[edit] Actions

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

[edit] External links

LUC subs
PTCentral

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 As such, some of the information contained herein may be outdated.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.