Shoulder dislocation is damage to the shoulder joint. It corresponds to the exit of the head of the humerus outside its cavity at the level of the scapula. It requires immediate treatment by the doctor.

Definition of shoulder dislocation

Shoulder dislocation is joint damage. It is one of the most frequent dislocations. The joint concerned is the scapulohumeral or glenohumeral joint. This connects the humerus (arm bone) to the scapula, better known as the scapula (flat, triangular bone located at the back of the thorax). The configuration of this joint contributes to the great mobility of the arm but also explains the high frequency of dislocations of the shoulder.

Normally, the spherical head of the humerus is inserted into the glenoid cavity of the scapula. However, sometimes the head of the humerus comes out of this cavity. This is called a dislocation of the shoulder.

Types of shoulder dislocations

First of all, it is possible to distinguish:

• a total dislocation of the shoulder which occurs when the head of the humerus comes completely out of the glenoid cavity of the scapula;
• a partial dislocation, or subluxation.

Then, other types of shoulder dislocations can be identified:

• previous dislocations which represent 95% of cases and which occur when the head of the humerus moves towards the front of the body;
• posterior dislocations that occur when the head of the humerus comes out towards the back of the body;
• lower dislocations which are characterized by a downward shift.

Causes of shoulder dislocation

Shoulder dislocations are caused by applying too much force to the joint. In other words, it is too violently pushed, pulled or twisted.

The dislocation can be caused by a direct impact on the shoulder or have an indirect origin, in particular during a fall on the hand or the elbow.

Some of the causes of shoulder dislocations include:

• sports trauma, especially when receiving blows on the shoulder;
• falls on the hand or elbow;
• road accidents.

Diagnosis of shoulder dislocation

A healthcare professional can usually diagnose a dislocated shoulder by a simple physical examination. This is supplemented by an interrogation on the pain felt and the circumstances of the injury.

In some cases, however, an x-ray may be requested by the healthcare professional. This medical examination can in particular make it possible to rule out or identify the presence of a bone fracture. Different management will be necessary in the event of a fracture of the scapula or humerus. 

People affected by shoulder dislocation

The risk of shoulder dislocation concerns everyone. It can happen at any time and at any age. However, it is often considered that certain athletes are more at risk because of their activity (skiing, judo, etc.). 

Having a dislocated shoulder in the past also increases the risk of having a new one. The joint is weakened. The risk of recurrence is particularly higher in:

• people who have already had a severe shoulder dislocation;
• people who have had a shoulder dislocation before the age of 30.

• Sharp pain in the shoulder: The dislocation of the shoulder results in severe pain in the scapulo-humeral joint. The pain can spread to the arm. The intensity is often such that it prevents any movement of the arm.
• Deformation and swelling: In the event of a dislocation of the shoulder, the head of the humerus completely or partially emerges from the glenoid cavity of the scapula. This displacement may be visible by a deformity which is usually accompanied by swelling in the shoulder.
• Other symptoms: Other signs can sometimes accompany a dislocated shoulder. Indeed, the latter can cause stretching or tearing of the tissues around the joint (ligaments, tendons, blood vessels, nerves, etc.). Motor and sensory deficits can then occur. For example, muscle spasms and numbness in the deltoid (shoulder muscle) may occur. In some cases, the dislocated shoulder is associated with a bone fracture.

Treating a dislocated shoulder involves replacing the joint. Be careful, this practice must necessarily be done by a healthcare professional. Under no circumstances should you try to replace your shoulder by yourself. The risk of complications is high. 

Replacing the joint is a painful practice. It is done after the administration of a sedative, analgesics or anesthetics. Different methods can be used by healthcare professionals:

• a traction-counter-traction;
• external rotation;
• Cunningham’s technique.

The joint is then immobilized with a sling or bandage. This immobilization lasts about three weeks. However, the healing time for a dislocated shoulder may vary from case to case. 

Finally, rehabilitation sessions are set up after immobilization.

It is difficult to prevent a shoulder dislocation. However, if it does occur, simple actions can prevent complications and limit pain. It is advisable to keep the arm as still as possible, especially with the help of a sling or splint. Applying ice can also help reduce swelling and relieve shoulder pain.