I dislocated my shoulder playing a neighborhood pick up game of volleyball. I never knew it was coming. One minute I spiked the ball over the net and the next I was on the ground in pain. How is that possible?

Many shoulder dislocations occur at work or during recreational or sports activities. Most people give the same report the first time it happens. They didn’t have pain, popping, or any symptoms to suggest the shoulder wasn’t stable.

Once a shoulder has dislocated, it can happen again. Warning signs and symptoms of repeated dislocations called prodromal symptoms may not be present. Most of the symptoms of first or repeat shoulder dislocation such as pain, muscle spasm, and loss of motion occur after it’s already happened.

Some people can pop their own shoulder out of the socket. This is called voluntary dislocation. Patients are advised not to do this since the soft tissue around the shoulder can get stretched, putting the person at greater risk of chronic dislocation.

The more times a shoulder is dislocated, the greater chance there is for rotator cuff tears around the shoulder.

The specific dynamics of the first dislocation may not be fully understood. Repetitive motion is a likely factor. Was there a partial tear of the rotator cuff already present? Or do the rotator cuff tears seen with shoulder dislocations happen after the joint dislocates? Researchers are investigating these questions with the hope of preventing shoulder dislocation and the damage that can occur.