I have supraspinatus tendonosis and am told biceps tendon and bursa implicated as well. For years I have slept on my stomach hugging one pillow in each arm and angling my head down. Now, with this injury I try to sleep on my back but can’t. I assume that it is bad to sleep on my stomach with my arms up, but honestly, its more comfortable than on my “good” side which hurts my ‘bad’ shoulder – guess I need a pillow under that arm. And oddly, snuggling up on my ‘bad’ side, with shoulder against the underneath-pillow, isn’t bad at all.
The humerus, glenoid, scapula, acromion, clavicle and surrounding soft tissues make up the shoulder. There are three significant articulations: the sternoclavicular joint, the acromioclavicular joint and the glenohumeral joint. The glenohumeral joint is the most commonly dislocated major joint in the body.
Ligaments and surrounding musculature, including the rotator cuff muscles, contribute to shoulder joint stability. The rotator cuff is composed of the four muscles: supraspinatus, infraspinatus, teres minor and subscapularis that interlock to function as one unit. These muscles help with internal and external rotation of the shoulder and importantly depress the humeral head against the glenoid as the arm is elevated. The tendons join together to form one tendon, the rotator cuff tendon. This passes through the subacromial space. The subacromial bursa, which has a large number of pain sensors, fills the space between the acromion and the rotator cuff tendon. [ 1 ]