I recently had surgery for an unstable shoulder. The doctor commented that the socket was tear-shaped. Is this normal? Did it contribute to the constant dislocations I was having?

Recent technology has allowed us to take pictures of various joints and form a 3-D view of them. As a result we now know that some shoulder sockets are tear-shaped. Others are oval.

At first there was some question that the shape might be linked to injury or instability. Scientists thought stress, load, and bone density might be related to the shape. However, a recent study comparing unstable joints to normal, healthy joints disproved this idea.

There was a shift in where the surfaces of the shoulder joint made contact. This change was linked to type of trauma (major or minor), not the shape of the socket.