Final answer:
For a PA radiograph with ulnar flexion focusing on the scaphoid bone, the carpal bones, including the navicular bone, as well as its anterior articulations with the three cuneiform bones and medial articulation with the cuboid bone, should be visible.
Step-by-step explanation:
When performing a PA (posteroanterior) radiograph with ulnar flexion to emphasize the scaphoid (navicular) bone, certain anatomical structures should be clearly visible. The goal is to properly demonstrate the carpal bones, especially the navicular bone, which articulates anteriorly with the three cuneiform bones: medial cuneiform, intermediate cuneiform, and lateral cuneiform. The radiograph should also reveal where the navicular bone articulates with the cuboid bone. It's important to check that the radial and ulnar deviation are minimized to ensure a clear image of the carpal bones.
The patient’s hand should be placed in the center of the image receptor with the elbow flexed at 90 degrees. The thumb should be in a relaxed position, with the fingers extended. By doing this, the weight-bearing aspect, or inferior surfaces of the carpal bones and specifically the navicular bone, will be profiled.