Which structure is demonstrated in profile medially on an internal rotation projection of the shoulder?

Which structure is demonstrated in profile medially on an internal rotation projection of the shoulder?

• A. Lesser tubercle
• B. Greater tubercle
• C. Coracoid process
• D. Humeral head

Answer: (A)

In an internal rotation projection of the shoulder, the lesser tubercle becomes prominently demonstrated in profile medially. This is because during internal rotation, the arm is turned inward, which allows the lesser tubercle to be positioned in a way that it faces directly outward, making it clearly visible on the radiographic image. The internal rotation aligns the lesser tubercle with the plane of the film, providing optimal visualization.

In contrast, the greater tubercle is located laterally and remains more obscured during internal rotation, appearing on the lateral aspect of the humerus. The coracoid process, while located medially, is not depicted in profile due to the rotation of the arm. Lastly, the humeral head is a significant structure, yet its position does not shift enough during internal rotation to show the lesser tubercle in the profile manner that is characteristic for this projection. Understanding the anatomy and orientation of these structures is crucial for radiographic interpretation and technique application in clinical practice.