Lets talk about the rotator cuff (aka: rotary cup or rotator cup)
The rotator cuff is comprised of 4 muscles that attach to different points on the shoulder blade and insert into the humerus (or your arm bone). The job of the rotator cuff is to lift your arm in many different directions (overhead, out to the side, and behind your back). When you lift your arm over your head the rotator cuff if functioning properly actually pulls down the humerus to avoid hitting a bone called the acromion (the bone on the outside of your shoulder). If your rotator cuff is torn, or you have tendonitis then you will most likely experience pain and/or weakness. Also you will have difficulty lifting your arm over your head, out to the side, or behind your back.
The four muscles of the rotator cuff are the suprapsinatus, infraspinatus, teres minor and subscapularis. The supraspinatus is the most common rotator cuff tendon that is torn.
Your shoulder blade and humerus (arm bone) work at the same time to lift your arm over your head. If there is a dysfunction of your rotator cuff or muscles that attach to the shoulder blade then you may be experiencing problems with your shoulder: loss of motion, weakness or pain. If you have questions about the rotator cuff or think you may have a shoulder problem post your comments below!