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 shoulder joint is constructed from the socket of the scapula and the humeral head, the ball at the top of the upper arm bone. The head of the upper arm is a large ball and important tendons insert onto it to move and stabilise the shoulder, but the shoulder socket, the glenoid, is small in comparison and very shallow. A cartilage rim, the labrum of the glenoid, deepens the socket and adds to stability. The acromio-clavicular joint lies above the shoulder joint proper and provides dynamic stability during arm movements, being made up from part of the scapula and the outer end of the clavicle.
The glenohumeral and scapulothoracic joints of the upper limb are acted on by large, strong, prime mover muscles as well as smaller stabilisers. The major back and hip muscles keep the shoulder stable to allow strong movements, the thoracic stabilisers keep the scapula stable so that the rotator cuff can act on a stable humeral head. The deltoid can then perform shoulder movements on the background of a solid base and allow precise placement and control of the arm for hand function to be optimal.
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.
As a person ages, the rotator cuff develops degenerative changes in its tendinous structures, causing small tears in the tendons which can enlarge until there is no continuity between the muscles and their attachments. This leads to loss of normal shoulder movement and can be very painful but is not always so and “Grey hair equals cuff tear” is a common saying. Physios work at rotator cuff strengthening, whilst in massive tears the main shoulder muscles can be progressively strengthened to improve function. Surgery is possible for massive, moderate and small rotator cuff tears and physiotherapists manage the post-operative protocols.
Osteoarthritis (OA) more commonly affects the hips and the knees, however the shoulder can be severely affected in which cases physiotherapy can help with advice, mobilisation of the joints and work on strength and joint motion. Once physiotherapy treatment has been tried then total shoulder replacement is the only remaining treatment option, surgical replacement occurring of the head of the arm bone and the socket of the shoulder blade. As the shoulder is referred to as a “soft-tissue joint” it is the balance and strength of the tendons, muscles and ligaments that determines a good outcome for the replacement. Physiotherapists closely follow the surgical protocols to get the optimal results.
Physiotherapy treatments include the assessment and management of many different shoulder pathologies such as shoulder fractures and dislocations, sub-acromial impingement, tendinitis, abnormal patterning and hypermobility. Physio treatment for fractures and dislocations depends on the severity and type of injury and follows the physiotherapy and surgical protocols. Patient education and muscle stabilising work is used for hypermobility, while biofeedback and correct muscle activity teaching is the treatment for abnormal patterning. Impingement physio is cuff strengthening and joint mobilisation, with joint injections and surgical acromioplasty if physiotherapy is not successful.
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Tags: injury management, physiotherapy, Fitness, Back pain
