Infraspinatus muscle

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Infraspinatus muscle
Image:Gray412.png
Muscles on the dorsum of the scapula, and the Triceps brachii. (Infraspinatus visible at center right.)
Image:Gray409.png
Muscles connecting the upper extremity to the vertebral column. (Infraspinatus visible at center left.)
Latin	musculus infraspinatus
Gray's	subject #123 441
Origin:
Insertion:
Blood:	suprascapular and circumflex scapular arteries
Nerve:	suprascapular nerve
Action:	Lateral rotation of arm & Adduction of arm
Dorlands/Elsevier	m_22/12549360

The Infraspinatus muscle is a lateral rotator of the glenohumeral joint and adductor of the arm.

It attaches medially to the infraspinous fossa of the scapula and laterally to the greater tubercle of the humerus.

The Infraspinatus is a thick triangular muscle, which occupies the chief part of the infraspinatous fossa; it arises by fleshy fibers from its medial two-thirds, and by tendinous fibers from the ridges on its surface; it also arises from the infraspinatous fascia which covers it, and separates it from the Teres major and minor.

The fibers converge to a tendon, which glides over the lateral border of the spine of the scapula, and, passing across the posterior part of the capsule of the shoulder-joint, is inserted into the middle impression on the greater tubercle of the humerus.

The tendon of this muscle is sometimes separated from the capsule of the shoulder-joint by a bursa, which may communicate with the joint cavity.

[edit] External links

LUC infs
SUNY Figs 03:03-04

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 As such, some of the information contained herein may be outdated.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