The muscles around the shoulder girdle can be broadly split into 2 groups:
- The movers: These are all the muscles around the shoulder that produce powerful movements such as lifting, i.e. The Pectorals, Latisimus Dorsi, Trapezius, Deltoid, Biceps and Triceps.
- The stabilisers: These are needed to control the head of the Humerus (the ball) in the Glenoid (the socket) while the arm is moving, This allows the powerful movers to work efficiently and to minimalise shoulder dysfuctions which can result in pain. The Rotator Cuff is a collective term given to the following muscles: Supraspinatus, Infraspinatus, Subscapularis and Teres Minor that form a strong cuff around the shoulder joint. A muscle becomes a tendon when it inserts into a bone, thus the term muscle and tendon are often synonymous.
The Supraspinatus muscle is the most commonly injured muscle. Its tendon runs under the bone on top of the shoulder and can get squashed between the underside of the shoulder blade and the head of the Humerus (the ball).
Commonly patients notice a loss of power in the arm, changed patterns of movement and often pain, especially at night. The aims of surgery are to try to address these problems, however a full range of movement and normal power is not always achievable. Not all tears are painful and to some extent may be a consequence of ageing; not all tears require surgery.