shoulder dislocation

anterior (subcoracoid)
- humerus --> beneath coracoid process, anterior to glenoid
- most frequent site + type of dislocation of any joint
- easily detected
- repeated dislocation ==> Hill-Sachs deformity and/or Bankart deformity
posterior
- 2 - 4% of shoulder dislocations
- 50% d/t seizures; trauma, electrical shock
- often missed on AP view: use "Y" or axillary view
- "rim" sign in acute dislocation
  - increased glenohumeral space (normal 6 mm --> widened to 14 mm)
- +/- compression fx of anterior surface of humeral head
20% ==> associated fx