Think of your shoulder joint as a round, smooth golf ball that is resting on a tee. This golf ball needs to stay in place for you to complete your swing and hit that ball, to see it soaring through the sky. Your shoulder joint is supported and stabilised by muscles and ligaments as well and just like the golf ball staying in place on the tee, your shoulder joint needs to be stable for you to move (or swing) your arm.
A shoulder dislocation is not just a joint injury
When a traumatic force is applied to your shoulder, big enough to force the head of the humerus out of the socket, it causes a dislocated shoulder. Your body will respond to the trauma of a shoulder dislocation by initiating a massive inflammatory reaction. A dislocated shoulder needs to be placed back into the right position as soon as possible, because this inflammation will lead to swelling and severe pain later on, which makes it harder to manage. Other structures like the static and dynamic stabilisers around the shoulder joint will always be injured as well. Muscles (usually the rotator cuff muscles), ligaments or the labrum can tear, nerves or arteries can be damaged and bones can even fracture.
If these stabilising muscles are not strong enough to withstand a force applied to your shoulder, it is so much easier for a shoulder dislocation to happen. They will be overwhelmed and unable to handle the force that is pulling or pushing your arm out of its socket. These muscles are pulled past their limits. This leads to a dislocated shoulder and a muscle injury.
The same counts for the ligaments around your shoulder. If you are very hypermobile or ‘double-jointed’, you naturally have more range than most people. It also means that your ligaments have become lax over time. Now, when a traumatic force is applied to your shoulder, the ligaments won’t be able to withstand it, and it leads to your arm ‘popping’ out of the socket. With ligaments that allow too much movement and that is stretched apart with a shoulder dislocation injury, your shoulder stability will not be what it should be. There is a great chance that this type of injury will happen to you again. Next time, it will happen a lot easier and won’t need as much force.
A partial dislocation (subluxation) happens when the humerus only ‘popped’ out of the socket partially or spontaneously relocates back into position by itself.
A shoulder can dislocate in four directions: Anterior (to the front), posterior (to the back), inferior (downwards) or superior (upwards). The severity of your injury and how you got injured, will determine in which direction your shoulder gets dislocated.
Types of Shoulder dislocations:
- Anterior shoulder dislocation: This is the most common direction in which a shoulder dislocates. It usually happens when you fall onto your arm that is stretched out or when you get a direct hit/tackle onto your shoulder. The head of the humerus will ‘pop’ out towards the front of your shoulder.
- Posterior shoulder dislocation: This is an uncommon form of shoulder dislocation. It usually happens with severe muscle contraction due to seizures or electrical shock or when you fall forward over your bike, directly onto your outstretched arm.
- Inferior shoulder dislocation: This is a very uncommon form of shoulder dislocation. Only with extreme forces, forcing the head of your humerus down and out of the socket, will you get an inferior shoulder dislocation.
It is very important to get your shoulder checked out after a shoulder dislocation. This way, instabilitiy and any other injured structures around the shoulder can be identified and you can get the right treatment from the start.