To demonstrate the lesser tubercle of the humerus in profile medially, which projection should be obtained?

The anteroposterior (AP) projection with internal rotation of the arm is the correct choice for demonstrating the lesser tubercle of the humerus in profile medially. This positioning rotates the humerus internally, allowing the lesser tubercle to be prominently displayed against the background of the greater tubercle and the humeral head, which effectively highlights it in the radiographic image.

Internal rotation places the arm so that the palm faces the thigh, facilitating the visibility of the lesser tubercle which is situated on the anterior aspect of the humerus. This positioning is essential for clearly visualizing and analyzing the anatomy or any possible pathologies associated with the lesser tubercle.

Other projections, such as the lateral view, tend to obscure the lesser tubercle and may instead focus on the greater tubercle due to the arm’s rotation and position. An AP projection with external rotation showcases the greater tubercle in profile while the lesser tubercle is positioned posteriorly and thus not visible. Lastly, a transaxillary projection is less commonly utilized and typically provides an alternative view, which may not effectively isolate the lesser tubercle’s visibility as desired in this situation.