Rotator cuff tear is caused by damage to any one of the four muscles or their ligaments that attach the muscle to the bone.
This happens because of acute injury, chronic overuse, or gradual aging. Tears can cause significant pain and disability with range of motion or use of the shoulder joint. The rotator cuff is made up of four muscles that help move and stabilize the shoulder joint.
The shoulder is a ball-socket joint that allows the arm to move in many directions. It is made up of the humeral head (the upper end of the bone of the upper arm) fitting into the glenoid fossa of the scapula (shoulder blade).
The humeral head is kept in place by the joint capsule and labrum, thick bands of cartilage that form an elongated cone where the humeral head fits.
The rotator cuff muscles are the dynamic stabilizers and movers of the shoulder joint and adjust the position of the humeral head and scapula during shoulder movement.
When the rotator cuff is torn or damaged, a variety of issues arise:
Pain and spasm limit the range of motion of the shoulder.
The muscles do not make the small adjustments within the joint to allow the humeral head to move smoothly.
Fluid accumulation within the joint due to inflammation limits movement.
Arthritis and calcium deposits that form over time limit range of motion.