CAMRT Radiography Practice Exam

How can one determine if the CR angle was adequate for an axial projection of the clavicle?

1. More than 50% of the clavicle appears on the image

2. The medial end is at the level of the 3rd rib

3. The entire clavicle is projected above the ribs

4. Most of the clavicle should be above the ribs and scapula

The correct answer is: Most of the clavicle should be above the ribs and scapula

The determination of whether the central ray (CR) angle was adequate for an axial projection of the clavicle primarily involves evaluating the position and visibility of the clavicle in relation to the surrounding anatomy. The statement regarding most of the clavicle being projected above the ribs and the scapula indicates that the CR angle has effectively raised the clavicle into a more horizontal position. This occurrence allows for improved visualization and minimizes superimposition of the clavicle over the ribs and scapula, which is essential for accurate assessment of the clavicle's condition or any potential injuries. In a well-performed axial projection, it is expected that the majority of the clavicle will be clearly above the ribs, thus indicating that the CR angle was sufficient to avoid obscuring the anatomical structure with overlying tissues. This positioning reduces the chances of diagnostic errors that can occur when parts of the clavicle are not adequately visualized. The other potential choices offer varying insights into the positioning of the clavicle but do not align as closely with the essential goal of ensuring maximum clarity for diagnostic purposes. For example, simply showing more than half of the clavicle or having the medial end at a specific rib level does not fully ensure the visibility needed to assess the clavicle accurately, nor does