Dislocated shoulder

Dislocated shoulder
The left shoulder and acromioclavicular joints, and the proper ligaments of the scapula.
Classification and external resources
Specialty	emergency medicine
ICD-10	S43.0
ICD-9-CM	831
DiseasesDB	31231
eMedicine	orthoped/440 radio/630 sports/152
MeSH	D012783
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A dislocated shoulder occurs when the humerus separates from the scapula at the shoulder joint (glenohumeral joint). The shoulder joint has the greatest range of motion of any joint, at the cost of low joint stability, and it is therefore particularly susceptible to subluxation (partial dislocation) and dislocation. Approximately half of major joint dislocations seen in emergency departments involve the shoulder.

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. In regards to recurrent dislocations, the supine apprehension test is a useful test in determining athletes who are predisposed to future dislocations.

There are three main types of dislocations: anterior, posterior, and inferior.

In over 95% of shoulder dislocations, the humerus is displaced anteriorly. In most of those, the head of the humerus comes to rest under the coracoid process, referred to as sub-coracoid dislocation. Sub-glenoid, subclavicular, and, very rarely, intrathoracic or retroperitoneal dislocations may also occur.

Anterior dislocations are usually caused by a direct blow to, or fall on, an outstretched arm. The patient typically holds his/her arm externally rotated and slightly abducted.

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Wikipedia