The shoulder joint is a ball and socket joint, the ‘ball’ compromises of the humeral head (upper arm bone) and the “socket” compromises of the glenoid fossa which is a small concave cavity of the shoulder blade.
This type of structure makes the shoulder joint highly mobile, however, very unstable. The stability of the shoulder joint is provided by both the ligaments of the shoulder and the muscles around it, such as rotator cuff muscles.
The Rotator Cuff is a group of 4 muscles;
- Supraspinatus
- Infraspinatus
- Subscapularis
- Teres minor
These 4 muscles provide strength and stability for the shoulder, working not only to provide movement of the shoulder joint but also to centralise the ball in the socket. They arise from the scapular (shoulder blade) and come together to form a covering around the head of the humerus. These muscles are involved in almost every type of shoulder movement, in fact they are “fine tuning” the movement of the arm within the joint capsule.
Because of their prominent role in the shoulder function, assessment of the rotator cuff muscles is a very important element of your physiotherapy session.
