The highlighted structure serves to prevent anterior dislocation of the femur onto the tibia. This type of dislocation is by far the communal type and typically results from external rotation, extension, and forced abduction. It can be auxiliary divided based on where the humeral head comes to lie, the division are as follows:
1. Subcoracoid: the most common
2. Subglenoid
3.Subclavicular
4. Intrathoracic: the very rare