shoulder pain

Learn more about specific shoulder conditions

The shoulder has the greatest range of movement of all joints in the human body. It is composed of three bones namely the clavicle (collar bone), scapula (shoulder blade), and humerus (upper arm),

There are two joints which link these bones together: the acromioclavicular (AC) joint and the glenohumeral (GH) joint and two additional joints which attach the shoulder complex to the rest of the body: the sternoclavicular (SC) joint and the scapulothoracic (ST) joint.

Working in unison it is estimated that over 1,500 positions can be assumed by the shoulder. However, the high degree of mobility comes at the cost of stability with the shoulder being the most common joint to dislocate (see shoulder dislocation).

Glenohumeral Joint

The glenohumeral (GH) joint is the largest and most obvious joint in the shoulder complex. It is described as a "ball and socket joint" and consists of an articulation between the glenoid fossa of shoulder blade (which forms the socket) and the head of the humerus(which forms the ball.).

One of the many reasons for such a high degree of mobility in the shoulder joint is that the socket of the joint is quite shallow and therefore the ball of the joint is able to move throughout its wide range without impeding on the surrounding bone. This is the opposite to the hip which has a much deeper socket. To combat this instability, the Glenohumeral joint relies on the balance, strength and control of muscles, ligaments/capsule and labrum (cartilage) to function properly.

The Acromioclavicular joint

The Acromioclavicular Joint (AC) is found on the top of the shoulder and is located between the collar bone and part of the shoulder blade defined as the acromion. Through this articulation, the collar bone can act as a strut maintaining the upper limb away from the thoracic cage and thus permitting a greater range of upper limb motion. The AC joint is supported by the acromioclavicular, coracoacromial ligament and coracoclavicular ligament.

Sternoclavicular Joint

Located more centrally is the Sternoclavicular joint which connects the chest bone and thecollar bone. This joint is the only bony link between the upper limb and the spine and similar to the knee, this joint has a small cartilaginous disc which acts like a “washer” between the bones to allow movement. Along with this fibrocartilaginous disc, support is provided to this joint by the articular capsule, sternoclavicular, interclavicular and costoclavicular ligaments 

Scapulothoracic Joint

The scapulothoracic joint is the fourth joint which makes up the shoulder girdle. It is located between the shoulder blade and the underlying rib cage. Although considered a “false joint”, movement at this joint should be precisely coordinated with movement at the glenohumeral joint. This is vital as the scapula houses the socket of the joint attached to it and any changesin the degree of movement between these two joints (scapulothoracic rhythm) can play a detrimental role in the function of the shoulder girdle leading to abnormal biomechanics and possible injury.

Rotator Cuff Muscles:

The Rotator cuff muscles comprise of the memorable SITS muscles i.e. Supraspinatus, Infraspinatus, Teres Minor and Subscapularis. These muscles are the main stabilisers of the shoulder girdle. They form a hood surrounding the head of the humerus at the front, back and upper aspect of glenohumeral joint.

Simultaneous contraction of the rotator cuff muscles keeps the head of the head humerus in the glenoid cavity (socket) of the shoulder blade. An example of this would be throwing a ball, whereby the head of the humerus is pulled forward and the rotator cuff muscles are stretched, as the ball is released. The rotator cuff muscles subsequently contract to prevent the joint dislocating forwards. 

Any changes in the biomechanics of the shoulder girdle in the absence of trauma can also lead to irritation of surrounding muscles and tendons. This is also very commonly seen at our city based practice whereby faulty posture leads to excessive stress being placed on the muscles of the shoulder girdle as they travel from the scapula to the upper limb.

To learn more about specific conditions click on the link in the table below:

(The list of diagnoses given below and subsequent explanations should not be considered a replacement for a full medical examination. Furthermore, we do not purport to treat all the Conditions listed. Should you wish to discuss any of these conditions with our chiropractors please do not hesitate to phone the clinic on 020 7374 2272 or email enquiries@body-motion.co.uk)