Anteroinferior dislocation of the shoulder is the commonest type of shoulder dislocation, it involves injury to the anteroinferior glenoid margin with or without injury to the posterosuperior humeral head.
The fibrocartilaginous labrum lines the glenoid cup, deepening it and making the glenohumeral articulation more congruent and stable.
Injuries to the anteroinferior glenoid involve labral tear (soft Bankart) or bony injury, either a fracture fragment or microtrabecular injury (osseous Bankart). There is usually an associated area of subchondral marrow edema at the humeral head with or without a depressed fracture. Needless to say that bone injuries are best assessed on CT.