Presentation
Left shoulder pain after pushing a heavy object.
Patient Data
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There is lack of overlap between the glenoid and the humeral head. The shoulder is rotated such that the humeral head has a 'light bulb' appearance.
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Both the lateral and especially the axillary view clearly demonstrate the relationship between the glenoid and the humeral head, and confirm a posterior dislocation.
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On both views the acromion (A), clavicle (Cl), coracoid process (Co) and glenoid (G) are identifiable, and the humeral head can be seen lying posterior.
The patient went on to have closed reduction in the emergency department.
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Post reduction film demonstrate the anterior rim of the glenoid and humeral articular surfaces appearing congruent.
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Dislocation film demonstrates no congruency between the glenoid articular suface (blue) and that of the humeral head (yellow). In addition due to internal rotation the proximal humeral head has a rounded appearance, likened to a light bulb (light green).
Post reduction film demonstrate the anterior rim of the glenoid (blue) and humeral (yellow) articular surfaces appearing congruent.
Case Discussion
Typical appearances of a posterior shoulder dislocation, demonstrating the relatively subtle AP findings.