For the arm and hand to work normally for all the tasks of daily activities and sports, the shoulder joint must be able to provide a wide range of motion to the upper limb. Unfortunately, the normal anatomic design that allows for great motion also places the shoulder joint at risk for injury.
Instability in the shoulder, a situation in which the shoulder slips out of place, often occurs due to an injury when the ligaments, which hold the ball and socket of the shoulder together, are stretched or torn.
In some circumstances, even without major injury, the shoulder can slip out of place. This usually occurs during sports that involve overhead repetitive stress on the shoulder, especially during overhead activity, such as baseball, tennis, volleyball and swimming.
In some situations, this problem can be controlled with therapeutic exercises designed to restore muscle coordination, strength and stamina. For some athletes, depending on the types of shoulder instability problems and their sports activities, braces can help to minimize the shoulder instability problem. However, in many circumstances, surgery is needed to repair or tighten the injured ligaments.