Rotator cuff tear results from tear of one or more of the rotator cuff muscles and their associated tendons. Which is the most commonly injured rotator cuff muscle?: (A) Supraspinatus, (B) Infraspinatus, (C) Teres minor, (D) Subscapularis
Answer is A. Supraspinatus is the most frequently injured muscle or tendon. Most of the injury result from overuse. Supraspinatus muscle: Its primary action is humeral abduction. The suprascapular nerve (C5-C6) and the suprascapular aery provide its innervation and blood supply.Infraspinatus muscle: Its primary action is lateral rotation of the humerus. The suprascapular nerve and the suprascapular aery provide its innervation and blood supply.Teres minor muscle: It causes lateral rotation of the humerus. The axillary nerve and circumflex scapular aery provide its innervation and blood supply.Subscapularis muscle: Causes medial rotation of the humerus with contraction. Upper and lower subscapular nerves and suprascapular, axillary, and subscapular aeries provide its innervation and blood supply.