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- See Rotator cuff;
- origin: infraspinatus fossa of scapula
- insertion: posterior aspect of greater tuberosity of humerus, capsule of shoulder joint; 
- demensions: infraspinatus has been shown to average 29 mm wide, with a mean medial-to-lateral width of 19 mm
- action: extension, horizontal extension and lateral rotation of humerus at the shoulder joint.
         - the infraspinatus is the primary muscle force resposible for external rotation;
         -  reversed origin insertion action: with the arm fixed, abducts the inferior angle of the scapula;
         - synergists: Teres Minor, Subscapularis, Deltoid;

- nerve supply: suprascapular, C5, C6 

 The role of the supraspinatus and infraspinatus muscles in glenohumeral kinematics of anterior should instability.

 Changes in the moment arms of the rotator cuff and deltoid muscles with abduction and rotation.

 Isolated paralysis of the infraspinatus muscle.

 Suprascapular neuropathy in volleyball players.

 Suprascapular nerve injuries with isolated paralysis of the infraspinatus.  

Infraspinatus Delamination Does Not Affect Supraspinatus Tear Repair.