The shoulder is the junction of three bones: the humerus (upper arm bone), the clavicle (collarbone), and scapula (shoulder blade). The ball-like head of the humerus fits into the cup-like end of the scapula known as the glenoid. This junction is commonly referred to as the shoulder socket, and is stabilized in part by the shoulder capsule, a series of ligaments that connects the humerus to the glenoid. When the ligaments weaken, the shoulder has a greater tendency to dislocate. This is known as instability, which can lead to greater and more painful shoulder conditions, especially dislocation and subluxation.
Causes and Risk Factors
Causes
Often an initial subluxation or dislocation forces the ligaments of the shoulder capsule to stretch. If the initial condition does not heal properly, instability will result and worsen over time. Risk Factors
Overhead sports, such as baseball, volleyball and swimming, pose a great risk of instability. Additionally, those with above-average joint laxity, or looseness of the ligaments, stand at great risk of shoulder instability.
Last updated: Jan-01-00
