Is a shoulder dislocation the same as a shoulder separation?
No! A shoulder dislocation is often confused with a shoulder separation, but these are two very different injuries! It is important to distinguish between these two problems because the issues with management, treatment, and rehabilitation are different. If you sustained a shoulder separation rather than a shoulder dislocation, you can read more about that injury in the information on separated shoulders.
What happens when you sustain a shoulder dislocation?
The shoulder joint is made of three bones which come together at one place. The arm bone (humerus), the shoulder blade (scapula), and the collarbone (clavicle) all meet up at the top of the shoulder. A shoulder separation occurs when there is an injury to the joint between the scapula and clavicle--this is called an acromioclavicular (or A-C) separation. A shoulder dislocation occurs when there is an injury to the joint between the humerus and scapula.The joint between the humerus and scapula, also called the glenohumeral joint, is a ball-and-socket joint--the ball is on the top of the humerus, and this fits into a socket of the shoulder blade called the glenoid. This joint is incredible because it allows us to move our shoulder though an amazing arc of motion--no joint in the body allows more motion than the glenohumeral joint. Unfortunately, by allowing this wide range of motion, the shoulder is not as stable as other joints. Because of this, shoulder dislocations are not uncommon injuries.
How does a shoulder dislocation happen?
A shoulder dislocation generally occurs after an injury such as a fall or a sports-related injury. About 95% of the time, when the shoulder dislocates, the top of the humerus is sitting in front of the shoulder blade--an anterior dislocation. In less than 5% of cases, the top of the humerus is behind the shoulder blade--a posterior dislocation. Posterior dislocations are unusual, and seen after injuries such as electrocution or after a seizure.
What are the symptoms of a shoulder dislocation?
Patients with a shoulder dislocation are usually in significant pain. They know something is wrong, but may not know they have sustained a shoulder dislocation. Symptoms of shoulder dislocation include:
- Shoulder pain
- Arm held at the side, usually slightly away from the body with the forearm turned outward
- Loss of the normal rounded contour of the deltoid muscle
How is the diagnosis of a shoulder dislocation made?
Diagnosis of a shoulder dislocation is usually quite apparent just by talking to a patient and examining their joint. Patients must be examined to determine if there is any nerve or blood vessel damage. This should be done prior to reduction (repositioning) of the shoulder dislocation. X-rays should be obtained to check for any fracture around the joint, and to determine the pattern of the shoulder dislocation.
Read more about the treatment of shoulder dislocations...
