What is the functional anatomy of the rotator cuff relative to supraspinatus tendonitis?

Updated: Dec 04, 2017
  • Author: Thomas M DeBerardino, MD; Chief Editor: Sherwin SW Ho, MD  more...
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The rotator cuff consists of 4 muscles, which control 3 basic motions: abduction, internal rotation, and external rotation. The supraspinatus muscle is responsible for initiating abduction, the infraspinatus and teres minor for controlling external rotation, and the subscapularis for controlling internal rotation. The rotator cuff muscles provide dynamic stabilization to the humeral head on the glenoid fossa, forming a force couple with the deltoid to allow elevation of the arm. It is responsible for 45% of abduction strength and 90% of external rotation strength.

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