Anterior Dislocation (Humerus)

Anterior shoulder dislocations account for 97 % of shoulder dislocations. They are usually due to indirect force, such as from abduction and internal rotation. The humeral head lies inferior and medial to the glenoid. As the dislocation occurs, the Hill-Sachs lesion and the Bankart fracture may occur as a result of the humerus striking the inferior rim of the glenoid. Labral (non-osseous) injuries may also result, leading to recurrent dislocations.
A AP radiograph of the shoulder. This shows marked overlap of the humeral head and the glenoid.

B Axillary radiograph of the shoulder. This view demonstrates the anterior dislocation of the humeral head (towards the coracoid).

C AP chest radiograph. The usual appearance of an anterior shoulder dislocation on a frontal radiograph.

Links to online textbooks

Wheeless' Orthopedics: discussion of anterior shoulder dislocation

References:

Lannigan A: Anterior glenohumeral dislocation J Accid Emerg Med. 1998 Sep;15(5):365. [See related articles]
Gleeson AP: Anterior glenohumeral dislocations: what to do and how to do it J Accid Emerg Med. 1998 Jan;15(1):7-12. [See related articles]

A	AP radiograph of the shoulder. This shows marked overlap of the humeral head and the glenoid.
B	Axillary radiograph of the shoulder. This view demonstrates the anterior dislocation of the humeral head (towards the coracoid).
C	AP chest radiograph. The usual appearance of an anterior shoulder dislocation on a frontal radiograph.