Presentation
Shoulder pain and stiffness following seizure.
Patient Data
Both frontal views, including what is supposed to be an external rotation view, are in internal rotation, giving the humeral head the appearnce of a light bulb. The axillary view shows posterior dislocation of the glenohumeral joint with posterior displacement of the humeral head with respect to the glenoid.
Case Discussion
A posteriorly dislocated humeral head is often "stuck" in internal rotation. Because the shoulder is locked in internal rotation, both the internal and external rotation views will be in internal rotation. The smooth appearance of the internally rotated humeral head has been likened to a light bulb, so a posteriorly dislocated humeral head locked in internal rotation has been called the light bulb sign.
Unable to process the form. Check for errors and try again.