Pseudodislocation of the humerus

Pseudodislocation of the shoulder results from an occult fracture with distension of the glenohumeral joint due to hemarthrosis that causes inferior displacement of the humeral head compared to the glenoid.

This may be mistaken for shoulder joint dislocation. Often, attempts are made to "relocate" the humeral head, which is both fruitless and painful. Therefore pseudodislocation of the humerus is one of the skeletal "do not touch" lesions.

Radiographic features

Plain radiograph

On an AP view, the head of the humerus is inferiorly subluxed and mimics a posterior shoulder dislocation.  An axial or trans-scapular view shows it is not anteriorly or posteriorly displaced and there is no glenohumeral dislocation.

CT/MRI 

May be useful for detection of occult fracture which is causing hemarthrosis.

Treatment and prognosis

The joint can be aspirated to show the normal position of the humeral head when the fluid has been removed from the joint.

Siehe auch:

• scheinbare Subluxation

und weiter:

• skelettale "do not touch"-Läsionen