Rotator cuff tear acromial shapes is likely both genetic and acquired. In the latter case, only age has been positively correlated with progression from flat to curved or hooked. The nature of mechanical activities, such as sports involving the shoulder, along with frequency and intensity of such sports, may be responsible for the adverse development. Sports such as bowling in cricket, swimming, tennis, baseball, and kayaking, are most frequently implicated. However, a progression to a hooked acromion may simply be an adaptation to an already damaged, poorly balanced rotator cuff that is creating increasing stress on the coracoacromial arch. Other anatomical factors that
Synovial sheath Synovial sheath A synovial sheath is one of the two membranes of a tendon sheath which covers a tendon. The other membrane is the outer fibrous tendon sheath. The tendon invaginates the synovial sheath from one side so that the tendon is suspended from the membrane by the mesotendon, through which the blood vessels reach the tendon, in places where the range of movement is extensive. The mesotendon disappears or remains in the form of narrow tendinous bands as threads known as vincula tendina. The synovial sheath is found where the tendon passes under ligaments and through osseofibrous tunnels; their