An axillary radiograph is obtained and shown below. Which of the following is the correct diagnosis?

A. Anterior shoulder dislocation
B. Distal clavicle fracture
C. Humeral head fracture
D.A. Proximal humerus fracture
D. Posterior shoulder dislocation
E. Proximal humerus fracture

Answer

Choice "E"“D” is the best answer. This is an applied anatomy question. Knowing basic bony anatomy is essential. A labeled axillary radiograph of the shoulder is included here. After identifying that the humeral head is not congruent and centered on the glenoid, the diagnosis of shoulder dislocation is made. Next, the direction of the dislocation must be determined, which and again, requires knowledge of shoulder anatomy. The coracoid process (#4 in the labeled figure below) is an anterior process and said to be the “lighthouse of the shoulder.” Use this figure to orient yourself to the anterior and posterior planes. Additional clues from the previous vignette include the position of the shoulder (adduction, internal rotation) and a history of seizures. Electrocution is another commonly cited mechanism for posterior shoulder dislocations. …show more content…
There is no clavicle fracture.

Choice "B" is not the best answer. There is no proximal humerus fracture.

Choice "C" is not the best answer. There is no fracture of the proximal humerus. The apparent indentation is a normal anatomic structure, the bicipital groove, that which contains the long head of the biceps as it travels distally from its origin at the supraglenoid tubercle.

Choice "E" is not the best answer. Use the coracoid process (#4) to orient yourself to the anterior plane. It then becomes apparent that the humeral head has dislocated posteriorly.

Choice "A" is not the best answer. There is no clavicle fracture anterior shoulder