The light bulb sign refers to the abnormal AP radiograph appearance of the humeral head in posterior shoulder dislocation. When the humerus dislocates it also internally rotates such that the head contour projects like a light bulb when viewed from the front 1. light bulb sign (hepatic hemangioma light bulb sign (adrenal pheochromocytoma In particular, the light-bulb sign may appear in cases where the humerus dislocates posteriorly and it also internally rotates such that the head contour projects like a light-bulb when depicted in the anterior-posterior X-ray views.
FileLightbulb sign posterior shoulder dislocation Roe vor und nach Reposition 001.jpg WikEM
The Lightbulb sign: As seen above, is due to internal rotation of the humeral head. The Rim sign, which is a widening of the glenohumeral joint, usually > 6mm The Trough Line sign, which is a vertical line on the medial aspect of the humeral head, that results from humeral head impaction. Mechanism Traditionally posterior dislocations have been associated with epileptic seizures, high energy trauma, electrocution and electroconvulsive therapy (ECT), although the incidence associated with ECT especially has decreased somewhat in recent years. 34 Images Summary Posterior shoulder instability and dislocations are less common than anterior shoulder instability and dislocations, but are much more commonly missed. Diagnosis is made radiographically in the setting of acute dislocations. Posterior dislocation is a rather rare injury, often misdiagnosed. The current report offers valuable insights regarding the anatomical background of this clinical entity and emphasizes the 'light-bulb sign,' which can be observed in anterior-posterior shoulder X-rays when there is a posterior dislo.
The 'Lightbulb Sign' doesn't always mean a posterior dislocation
Presentation Work up for trauma. Patient Data Age: 25 years Gender: Male x-ray The humeral head is forced into the internal rotation as it dislocates posteriorly, giving the appearance of a lightbulb sign. Case Discussion Posterior dislocation of the right shoulder on frontal projection can be difficult to identify. Revisions: 12 format_list_bulleted Contents add The shoulder is a highly mobile joint that sacrifices stability for an increased range of movement. As a consequence of this trade off, dislocations are common, with an incidence of up to 1.7% in the general population. In addition, the lightbulb sign also refers to abnormal configuration of the humeral head on radiograph in posterior shoulder dislocation. 15 Our study has number of limitations. First, the sample size of our cohort is too small to endorse this finding as a reliable sign, although it may be explored in the future as a distinguishing feature. lightbulb sign: fixed internal rotation of the humeral head which takes on a rounded appearance 2 trough line sign: dense vertical line in the medial humeral head due to impaction of the humeral head loss of normal half-moon overlap sign, in which the glenoid fossa appears vacant due to the lateral displacement of the humeral head
Shoulder Dislocation Reduction Immobilisation
Photo A traditional incandescent light bulb, with its characteristic cone like shape. Photograph courtesy of Roger Bickle, Melton Mowbray, UK. Case Discussion A posterior shoulder dislocation on the AP radiograph adopts a shape described at appearing like a traditional lightbulb. 1 article features images from this case Case Discussion. The lightbulb sign occurs when the humeral head is posteriorly dislocated causing humeral head internal rotation giving this appearance. A second view should be used to confirm these findings, or CT when positioning can be difficult due to pain and/or associated fracture.
Posterior dislocation, "light bulb sign" Source: Dr. Alexandra Stanislavsky; radiopaedia.org While the axillary or scapular Y views often help demonstrate posterior shoulder dislocations, the. (A) Lightbulb sign demonstrating rounded appearance of the humeral head with a posterior glenohumeral dislocation. (B) Axillary radiograph of locked posterior glenohumeral dislocation. Figure 17-4. Velpeau axillary x-ray.
Shoulder examination station OSCE
Right shoulder anterior-posterior (AP) radiogram showed no fracture but the lightbulb sign (Fig. 1), that is, the humeral head resembling a lightbulb on AP shoulder radiogram because the humeral head is held in fixed internal rotation after posterior shoulder dislocation, was missed by the attending emergency physician. Description. Lightbulb Sign in Posterior Shoulder Dislocation - Shoulder X-Ray - Lil Bone Peep @peds_sports_med #Lightbulb #Sign #Posterior #Shoulder #Dislocation #XRay #radiology #msk.
