Posterior Dislocation of the Shoulder

1st image: normal AP
2nd and 3rd images: post dislocation on AP and lateral

Mechanism of Injury
Direct force to anterior aspect of shoulder
Electric shock, seizures with arm in adduction, flexion and internal rotation
Examination
Painful shoulder with arm held in internal rotation and unable to externally rotate
Palpable head posterior to shoulder
X-rays
AP and Y-scapular views; axillary views if possible
AP view: light bulb sign, loss of overlap of humeral head on glenoid rim
Y-scapular and axillary views: humeral head posterior to glenoid cavity
Management
Prompt reduction at A&E after X-rays reviewed
IV pethidine 50mg +/- sedation with IV midazolam
Traction on arm with shoulder in 90 abduction and then externally rotating the arm
Place upper limb in triangular arm sling after reduction, +/- strap arm to chest
Check for neurovascular injuries after reduction
Check X-rays to confirm reduction and exclude fracture
If reduction successful: Analgesics. TCU Ortho SOC within 2 weeks
If reduction unsuccessful: contact Ortho MO-on-call to attempt reduction at the A&E