In this injury, a fall or blow causes the top of your arm bone to pop out of the shoulder socket. Unlike a lot of joints in your body — your elbow, for instance — the shoulder is incredibly mobile. You can twist and move your upper arm in almost any direction. But there’s a price for this ease of movement. The shoulder joint is inherently unstable, prone to slipping out of place.
In severe cases of a dislocated shoulder, the tissue and nerves around the shoulder joint get damaged. If you keep dislocating your shoulder, you could wind up with chronic instability and weakness.