Dislocations of the shoulder occur when the head of the humerus is forcibly removed from its socket in the glenoid fossa. Other rare types of dislocations include luxatio erecta, an inferior dislocation below the joint, and intrathoracic, in which the humeral head gets stuck between the ribs.Many physicians believe that age is less of a predisposing risk factor for redislocation than activity level
A diagnosis of shoulder dislocation is often suspected based on patient history and physical examination. Radiographs are made to confirm the diagnosis. Most dislocations are apparent on radiographs showing incongruence of the glenohumeral joint. Posterior dislocations may be hard to detect on standard AP radiographs, but are more readily detected on other views. After reduction, radiographs are usually repeated to confirm successful reduction and to detect bony damage. After repeated shoulder dislocations, an MRI scan may be used to assess soft tissue damage.