1) convulsive muscle contraction may produce powerful symmetrical traction forces, leading to bilateral even symmetrical joint dislocations and avulsion fractures; 2) do not miss simultaneous bilateral shoulder dislocations or fractures after convulsive events; 3) powerful external retraction forces to the shoulder girdle may induce bilateral traction neuropathy; 4) rarely, direct impact on both arms can cause bilateral AC joint disruptions.

Seizure disorders are known to cause fractures such as vertebral and rib fractures in case of convulsive events. Avulsion fractures may also occur due to sudden and unopposed muscle contractions. Joint dislocations, however, are less often encountered in such a scenario. Jerky retropulsion of the shoulder girdle may cause bilateral nerve traction injuries without osseous or articular damage. Furthermore, bilateral simultaneous AC joint dislocations may also occur in the event of a single impact on both arms.

Imaging findings of six patients showing both similar and different but bilateral and symmetrical shoulder (girdle) abnormalities will be displayed (plain radiographies, CT, and MR images). Three of them (two females, one male) suffered bilateral symmetrical shoulder dislocation each (one anterior-inferior, one posterior, and one another posterior dislocation where bilateral occurrence has been missed). Another male patient sustained bilateral avulsion of the lesser tubercles. The fifth patient (male) appeared with winged scapulae after sustaining a jerky retraction injury to his shoulder girdle while riding a...

Seizue episodes are capable to induce severe glenohumeral fracture-dislocations, both symmeztrically and simultaneously. While undisplaced tubercle fractures may be missed on plain films, shoulder dislocations may occur at both sides at the same time-point. In addition, synchronous bilateral AC joint injuries may occur under certain circumstances, depending on trauma mechanism. Rarely, jerky external retraction of the shoulder girdle can cause nerve route overstretching, resulting in neural traction damage, thus leading to subsequent muscle atrophy and weakness.

1. Cautero E, Gervasi E: Locked bilateral posterior fracture-dislocation of the shoulder in an epileptic patient: case report. Joints 2014; 2(3): 146-148. 2. Ballesteros R, Benavente P, Bonsfills N et al.: Bilateral anterior dislocation of the shoulder: review of 70 cases and proposal of a new etiological-mechanical classification. J Emerg Med 2013; 44(1): 269-279. 3. Jansen H, Frey SP, Doht S et al.: Simultaneous posterior fracture-dislocation of the shoulder following epileptic convulsion. J Surg Case Rep 2012: (11). 4. Eni-Olofu DO, Hobbs, NJ: Floating clavicle...

Thomas Grieser, MD Consultant in Radiology Central Hospital Augsburg Dept. of Diagnostic and Interventional Radiology and Neuroradiology 2 Stenglin Str D-86156 Augsburg GERMANY Email: [email protected]