Key Points:

  • Posterior shoulder dislocations (PSD) are most likely associated with reverse Hill-Sachs lesion is a rare injury, often missed or misdiagnosed
  • CT and MRI scans are needed to detect the associated bone and soft tissue lesions usually
  • There is radiographic absence of external rotation on images in a standard shoulder series, presence of a lightbulb sign making head look round, trough line sign which is a dense vertical line in the medial humeral head, loss of normal half-moon overlap sign where glenoid fossa appears vacant, and rim sign which is a widened glenohumeral joint
  • Reverse Hill-Sachs defect and a reverse Bankart lesion are also commonly seen

Credit: Case contributed by Matt Corey MD to radRounds Radiology Network