This wear and tear can lead to weakening of the rotator cuff tendons, through a condition know as impingement. The rotator cuff tendons are also subject to degeneration as we age. Let's look at how this can occur. The tendons of four muscles form the rotator cuff. The muscles are called the supraspinatus, infraspinatus, teres minor, and subscapularis.
Tendons attach muscles to bones.
Muscles are able to move bones by pulling on these tendons. The part of the scapula that makes up the roof of the shoulder is called the acromion. Between the acromion and the rotator cuff tendons there is a bursa. There are many bursae all over the body where tissues must move against one another. The bursa is a lubricated sac of tissue that protects the muscles and tendons as they move against one another.