Rotator Cuff Tear
The bones that make up the shoulder and arm are connected in a ball-and-socket joint that is kept in place by the rotator cuff. The rotator cuff is an assembly of four muscles that cover the head of the humerus or the ‘ball’ part of the joint.
Rotator cuff tears occur when a tendon or muscle no longer attaches itself to the head of the humerus which can inflame the muscles, inhibit movement and irritate lubricating sacs called bursa that allow your arm to move smoothly. Rotator cuff tears are categorized into three types: partial- and full-thickness tears which come from repetitive stress, low blood supply to the rotator cuff disabling the muscle’s own ability to heal itself, and bone spurs.
For more information visit the American Academy of Orthopaedic Surgeons: https://orthoinfo.aaos.org/en/diseases–conditions/rotator-cuff-tears/