The shoulder joint is surrounded by a thick band of tissue, called the capsule. The capsule is re-enforced in part by small, but very strong, ligaments designed to maintain normal joint stability. It can take quite a lot of force to tear the capsular ligaments.The shoulder usually only dislocates (or comes out of its socket) when a great deal of force has been applied to the shoulder. This is called a traumatic dislocation, or if they only partially dislocate, this is a subluxation.
Unfortunately, once a shoulder has been dislocated, there is a high chance of recurrence. Some people naturally have loose shoulder joints, and their shoulder can slip in and out of the joint more easily. When the shoulder comes out of the joint in more than one direction, this is known as “multi-directional instability” and can cause problems that affect normal activities of daily living such as reaching up high or over behind your head.
It is always important to have someone assess a dislocation as not only are the ligaments affected, but sometimes there can be small injuries to the bones in the shoulder. A Bankart lesion occurs when the cartilage or bone from the glenoid is damaged. A Hills Sachs lesion occurs when the head of the humerus is impacted and suffers an inwards fracture. Recurrent dislocations or dislocations with bony or cartilage damage often require surgical stabilisation.
Physiotherapy aims to help pain and improve function by helping to strengthen the muscles around the shoulder joint to help stabilise the shoulder joint and the muscles which provide support to the whole shoulder complex.
The shoulder joint is a ball and socket joint. A ball at the top of the upper arm bone (humerus) fits neatly into a socket, called the glenoid, which is part of the shoulder blade (scapula). The glenoid is surrounded by a ring of fibrous cartilage called the labrum for stabilization of the shoulder joint.
Sports that involve overhead movements and repeated use of the shoulder at your workplace may lead to sliding of the upper arm bone from the glenoid. The dislocation might be a partial dislocation (subluxation) or a complete dislocation causing pain and shoulder joint instability. The shoulder joint often dislocates in the forward direction (anterior instability), and sometimes in the backward or downward direction.
Your doctor will examine your shoulder and may order an X-ray to confirm the diagnosis.
