In a true AP projection of the shoulder, which structure should be seen in profile laterally?

• A. Coracoid process
• B. Greater tubercle
• C. Humerus
• D. Scapula

Answer: (B)

In a true anteroposterior (AP) projection of the shoulder, the greater tubercle of the humerus is the structure that appears in profile laterally. This positioning is essential because the greater tubercle serves as an important landmark for identifying the true position of the shoulder joint. When the arm is positioned in an AP view, the humerus is externally rotated, allowing for the greater tubercle to be visible on the lateral side. This visibility helps in assessing any potential injuries or abnormalities and ensures proper alignment of the shoulder joint in imaging.

The other structures mentioned may not be clearly visible in profile in this specific view. The coracoid process, while sometimes visible, does not present as prominently as the greater tubercle in a standard AP projection. Additionally, the humerus and scapula will be more general in appearance rather than specifically highlighted in profile, which is why the greater tubercle is the key focus in this projection.