American Society of Radiologic Technologist (ASRT) Practice Exam

When performing a lateral projection of the fourth toe, where is the central ray directed?

1. Proximal interphalangeal joint

2. Distal interphalangeal joint

3. Metatarsophalangeal joint

4. Tarsometatarsal joint

The correct answer is: Proximal interphalangeal joint

For a lateral projection of the fourth toe, the central ray is directed to the proximal interphalangeal joint. This is the correct direction because the primary focus of the lateral projection is to visualize the anatomy of the toe, particularly to capture the bone structures and any potential pathologies in the region. By centering the x-ray beam at the proximal interphalangeal joint, the resulting image will provide an accurate representation of the bone alignment and relationships within the toe, allowing clinicians to assess for fractures, joint issues, or other abnormalities effectively. The proximal interphalangeal joint serves as a pivotal point for this projection, as it is located between the first and second phalanges of the fourth toe, making it essential for optimal imaging. Proper positioning and central ray alignment ensure reduced distortion and increased detail in the radiographic image. Radiologic technologists must be meticulous about the central ray placement to obtain clear and diagnostically useful images.