Bankart and variants

Bankart-lesions and variants like Perthes and ALPSA are injuries to the anteroinferior labrum.
These injuries are always located in the 3-6 o'clock position because they are caused by an anterior-inferior dislocation.
The only exception to this rule is the reverse Bankart, which is the result of a posterior dislocation and injury to the inferoposterior labrum.
Bankart tears may extend to superior, but this is uncommon.

• Bankart
  Detachment of the anteroinferior labrum (3-6 o'clock) with complete tearing of the anterior scapular periosteum with or without an osseus fragment of the glenoid.
• Reverse Bankart
  Detachment of the posteroinferior labrum (6-9 o'clock) with tearing of the posterior scapular periosteum with or without an osseus fragment of the glenoid.
• Perthes
  Detachment of the anteroinferior labrum (3-6 o'clock) with medially stripped but intact periosteum.
• ALPSA = Anterior Labral Periosteal Sleeve Avulsion.
  Medially displaced labroligamentous complex with absence of the labrum on the glenoid rim.
• GLAD = GlenoLabral Articular Disruption.
  Represents a partial tear of anteroinferior labrum with adjacent cartilage damage.

Reference