- Infraspinatus muscle
Muscle infobox
Name = PAGENAME
Latin = musculus infraspinatus
GraySubject = 123
GrayPage = 441
Caption = Muscles on the dorsum of thescapula , and theTriceps brachii muscle : #3 isLatissimus dorsi muscle
#5 isTeres major muscle
#6 isTeres minor muscle
#7 isSupraspinatus muscle
#8 isInfraspinatus muscle
#13 is long head ofTriceps brachii muscle
Caption2 = Muscles connecting the upper extremity to thevertebral column .
Origin =infraspinous fossa of thescapula
Insertion = middle facet ofgreater tubercle of thehumerus
Blood =suprascapular andcircumflex scapular arteries
Nerve =suprascapular nerve
Action =Lateral rotation of arm &Abduction of arm and stabilizeshumerus
MeshName =
MeshNumber =
DorlandsPre = m_22
DorlandsSuf = 12549360
The Infraspinatus muscle is a thick triangularmuscle , which occupies the chief part of theinfraspinatous fossa .Origin and insertion
It attaches medially to the
infraspinous fossa of thescapula and laterally to thegreater tubercle of thehumerus .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 .Relations
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.Action
It is a lateral rotator of the
glenohumeral joint andadductor of the arm.The Infraspinatus and Teres minor rotate the
head of the humerus outward (external rotation); they also assist in carrying the arm backward. Studies by Lastayo, w., etc. have shown the infraspinatus to be the major external rotator of the shoulder in comparison with the teres minor.Fact|date=October 2007ee also
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Rotator cuff External links
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