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.
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.
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.