Learning Radiology xray montage

Anterior Dislocation of the Shoulder


  • Glenohumeral dislocation most common shoulder dislocation (85%)
  • Glenohumeral joint dislocations make up >50% of all dislocations in the body
  • Anterior / subcoracoid shoulder dislocation (96%)
  • Mechanism
    • External rotation and abduction and external rotation
  • Age
    • Younger individuals
  • May be associated with
    • Hill-Sachs defect (50%) is a depression fracture of posterolateral surface of humeral head from impaction of the head against glenoid rim in subglenoid type
      • Best demonstrated on the AP projection with the arm internally rotated
    • Bankart lesion is a fracture of anterior aspect of inferior glenoid rim
      • Only cartilaginous portion of glenoid labrum may be fractured which may only be visible on MRI
    • Fracture of greater tuberosity (15%)
  • Complications
    • Recurrent dislocations (40%)
    • Post-traumatic arthritis
    • Injury to axillary nerve or artery 


Anterior Dislocation of the Humeral Head: Top image shows humeral head displaced from glenoid and lying inferior to the coracoid process (red arrow); the middle image demonstrates a defect along the posterolateral aspect of the head, which is the Hill-Sach's deformity (green arrow). The lower image is the scapular Y view (blue line outlines scapula). The head lies in a subcoracoid (i.e. anterior location). The white arrows point to the acromion.