Rotator cuff stability vary according to their stiffness and the direction of the force they apply upon the joint. In addition to stabilizing the glenohumeral joint and controlling humeral head translation, the rotator cuff muscles also perform multiple functions, including abduction, internal rotation, and external rotation of the shoulder. The infraspinatus and subscapularis have significant roles in scapular plane shoulder abduction (scaption), generating forces that are two to three times greater than the force produced by the supraspinatus muscle. However, the supraspinatus is more effective for general shoulder abduction because of its moment arm. The anterior portion of the supraspinatus tendon is
Rotator cuff tear these studies we see that the percentages of the prevalence of a rotator cuff tear are very close in number so these numbers show us the prevalence of rotator cuff tears in the general population. In an autopsy study of rotator cuff tears, the incidence of partial tears was 28%, and of complete rupture 30%. Frequently, tears occurred on both sides and the frequency increased with age. The frequency was also higher in females. Other cadaver studies have noted intratendinous tears to be more frequent (7.2%) than bursal-sided (2.4%) or articular-sided tears (3.6%). However, clinically, articular-sided tears are found to