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
Mucous sheaths of the tendons around the ankle the level of the tip of the malleolus, while that for the Flexor digitorum longus is slightly higher; the former is continued to the base of the first metatarsal, but the latter stops opposite the first cuneiform bone. On the lateral (outer) side of the ankle a sheath which is single for the greater part of its extent encloses the Peronæi longus and brevis. It extends upward for about 4 cm. above the tip of the malleolus and downward and forward for about the same distance. Mucous sheaths of the tendons around the ankle The mucous sheaths of the tendons