Physiotherapy for the Shoulder
The function of the human arm is to allow placement of the hand in useful positions so the hands can perform activities where the eyes can see them. Because of the huge range of positions required the shoulder is very flexible with a large motion range, but this is at the expense of some reduced strength and greatly reduced stability. A “soft tissue joint” is often a description of the shoulder, indicating it is the tendons, muscles and ligaments which are important to the joint’s function. Shoulder treatment and rehabilitation is a core physiotherapy skill.
The humeral head and the glenoid of the scapula make up the glenohumeral joint, with the glenoid being small and flat and the humeral ball being large and partly spherical. The main ligaments and shoulder tendons insert on the humeral head, giving the movement and support the joint requires. The socket is made deeper by the glenoid labrum, a rim made of cartilage, which aids joint stability. Above the shoulder lies a joint between the outer end of the clavicle and the acromion, part of the scapula. This is a stability joint for arm movement and called the acromio-clavicular joint.
A great many muscles act on the shoulder joint and on the other joints in the shoulder girdle, the acromioclavicular, sternoclavicular and scapulothoracic joints. The glenohumeral and scapulothoracic joints are acted upon by the major stabilisers and movers in the area, varying from power muscles which allow forceful work to stability muscles such as serratus anterior and the rotator cuff to smaller movement muscles such as deltoid. The muscles must keep the relationship between the shoulder blade and the thorax and ribcage steady and under control for the glenohumeral joint to also enjoy stability and precise movement.
The shoulder muscle tendons become flatter and thinner as they approach and then insert themselves onto the head of the humerus. By this way the rotator cuff, a group of four muscles including the supraspinatus, infraspinatus, teres minor and subscapularis, is able to exert its forces on the humeral head. The tendons coalesce as they surround and insert onto the ball of the humerus, forming a cuff around the ball, centering the ball on the socket to counter the tendency to slide upwards under muscle activity. Keeping the ball centred on the socket means the larger and more powerful muscles can perform functional shoulder and arm movements.
The rotator cuff degenerates with age, small tears appearing across its substance which can progress to massive tears, completely interfering with muscular function of the shoulder. Rotator cuff tears are often painful but it is not clear exactly why, as many older people have tears and do not have pain. Physiotherapists work to strengthen the rotator cuff or by exercising the main shoulder muscles without gravity resistance and gradually increasing the effort. Physios also work on rehabilitation after rotator cuff surgery for rotator cuff tears, following the detailed protocols for small, medium, large or massive rotator cuff tears.
The shoulder joint is not typically affected by OA (osteoarthritis) but when it is physiotherapists treat arthritic shoulders by joint mobilisations, muscle strengthening and ranges of motion. Once physio has nothing else to offer, total shoulder replacement is one of the further options, with various surgical techniques involving replacing the humeral ball and the scapular socket either anatomically or in reverse. The shoulder is often called a “soft-tissue joint” as the soft tissues, their strength and balance, are vital to the function of the joint. Post-operative physio management is essential as the correct protocol must be closely followed to ensure success.
Physiotherapists treat many other types of shoulder problems such as impingement, tendinitis, hypermobility, abnormal muscle patterning, fractures and dislocations. Impingement is treated by strengthening the rotator cuff or by subacromial injection or acromioplasty operation, where the end of the acromion can be excised. Tendinitis is treated by direct treatment of the tendon and graded strengthening and hypermobility by stability work and accepting the limitations dictated by the condition. Abnormal muscle patterning is managed by teaching normal patterns functionally and fractures and dislocations by the protocols laid down by the surgeons and trauma physiotherapists.