Posterior shoulder dislocation occurs when the arm bone slides backward from the socket. It is less common than anterior shoulder dislocation and occurs when a person raises their arm in front of ...

Posterior shoulder dislocation occurs when the top of the upper arm bone, known as the humerus, moves backward out of its socket. This causes pain, muscle spasms, and a limited range of motion.

Anterior deltoids. When you move your thumb inward, you use your anterior deltoids.You also use them when you move your arm forward in front of your body. Lateral deltoid. If you move your arms ...

Chronic shoulder instability occurs when the top of your arm bone, also called the head of your arm bone, slips out of its socket. This can cause your shoulder to dislocate, or it may itself be ...