The shoulder is one of the most complex joints in the body. It is a ball and socket joint which allows for large range of motion. The shoulder girdle is composed of the clavicle and scapula which articulates with the humerus to make the glenohumeral joint.
The Scapula and Periscapular Muscles
The scapula, shoulder blade, is attached to the skeleton by the acromioclavicualr joint, otherwise it has no direct skeletal attachments to the skeleton and it fully supported on the thorax by musculature. Thus, it is very important that the muscles around the scapula, the periscapular muscles, are strong and functioning well for the shoulder joint to function at pain free capacity. With periscapular muscle weakness comes scapula dyskinesia, incorrect scapula movement, which can cause shoulder pain.
The Glenohumeral Joint
The glenohumeral joint is a ball and socket joint, where the head of the humerus sits in the glenoid socket, the glenoid is shallow and the head of humerus sits in it like a golf tee. To prevent the head of the humerus from falling out of the gelnoid there is a labrum which acts as a seal around the joint. The rotator cuff muscles keep the head of the humerus within the small glenoid fossa and stabilise the joint through movement to prevent dislocation.
Rotator Cuff Muscles
The rotator cuff is made up of: supraspinatus, infraspinatus, trees minor and subscapularis. The muscles originate on the scapula and connect to the head of the humerus, creating a cuff around the glenohumeral joint. They are essential in stabilising the shoulder in every type of shoulder movement. Balanced strength of the rotator cuff muscles is essential in maintaining function and avoiding pain of the entire shoulder girdle.
If the periscapular muscles or rotator cuff muscles are disfunctioning, it can lead to shoulder pain, neck pain, and cause functional impairment and a reduced quality of life.
Shoulder pain can just be caused by muscle imbalances, weakness, joint stiffness or increased joint laxity. Physiotherapists can assess, diagnose and determine a specific management plan for a shoulder problem to help reduce pain and improve function. It is important to see a physiotherapist to receive the correct exercises, learn correct movement and postural biomechanics because incorrect form can prematurely affect quality of rotator cuff muscles and tendons due to repetitive strains. Sometimes pain can be caused by a more serious pathology for example rotator cuff tear. Rotator cuff tears are a common injury of the shoulder than can occur at any age due to repetitive overuse or secondary to trauma. Incidence of injury increases with age, however some rotator cuff tears are asymptomatic. It is possible to manage rotator cuff tears conservatively with physiotherapy, not all rotator cuff tears require surgery. Overall, the shoulder is an amazing joint which moves through great ranges of motion that allows us to swim, throw a ball, reach for a high shelf, drive and many other activities. It is a vital to have functioning shoulder to achieve daily activities, as such it is very important to ensure your shoulders are strong and move with the correct biomechanics to prevent injury and pain.