If you've ever had a dislocated shoulder, you know it's an injury that can cause severe pain and discomfort. But how serious is it, and what can you do to prevent it from happening?

To understand what a dislocated shoulder is, it helps to be familiar with the makeup of the shoulder itself. Three bones make up your shoulder joint:

• Collarbone (clavicle)
• Shoulder blade (scapula)
• Upper arm bone (humerus)

The top of the arm bone looks like a ball and fits into a socket (glenoid). A dislocated shoulder is when the ball pops out of the shoulder socket, the injury is called a dislocated shoulder.

A dislocated shoulder can be partial or complete. A partial dislocation means the ball is partially out of the socket. In contrast, a complete dislocation means the ball has come out. Both injuries can cause pain and swelling and prevent you from using your shoulder fully.

Dislocated shoulders are common, making up 50% of all joint dislocations. Symptoms include:

• Severe pain in the shoulder
• Swelling and bruising in the upper arm and shoulder area
• Weakness or numbness in your arm, hand, fingers, or neck
• Muscle spasms
• Trouble moving your arm properly

Shoulder injuries can occur for many reasons, including:

• Playing sports
• Car accidents
• Falling on your shoulder 
• Seizures and electric shocks, which can cause shoulder muscles to contract and pull the ball out of place

If you think you have dislocated your shoulder, you should never try to pop it back into place yourself. Attempting to do so could cause damage not only to the joint but also to shoulder muscles and ligaments, as well as blood vessels and nerves.

Instead, see a doctor as soon as possible. In the meantime, keep moving your shoulder as little as possible. Icing the area can help reduce pain and swelling.

To diagnose shoulder injuries, your doctor will do a physical exam. An X-ray might be necessary as well. Once the doctor has diagnosed a dislocated shoulder, they will perform a closed reduction, which is the process of placing the ball of the upper arm bone back into the shoulder socket. The pain usually stops when the shoulder joint is back in place.

After the joint is in place, your doctor may recommend immobilizing your shoulder in a sling or other device for several weeks. You can also ice the area three or four times a day during this time.

After the pain and swelling have gone down, your doctor will likely give you rehabilitation exercises. These exercises will help strengthen your muscles and restore your range of motion, helping to prevent future dislocations.

If repeated dislocations become a problem, wearing a brace can help. But when therapy and bracing fail to help, you might need surgery to repair the shoulder joint's ligaments.