Question

What is the purpose of the CR angle on the lateral projection of the knee?

a) To project the patellofemoral joint
b) To prevent foreshortening of the femur
c) To open the joint space of the knee
d) To visualize the intercondylar eminence

Answer 1

The CR angle on the lateral projection of the knee is designed to ensure clear visualization of the intercondylar eminence, a key structure for the attachment of cruciate ligaments and the stabilization of the knee joint.

Step-by-step explanation:

The purpose of the central ray (CR) angle on the lateral projection of the knee is to visualize the intercondylar eminence. This anatomical structure is where the anterior and posterior cruciate ligaments are anchored. These ligaments are crucial for the stabilization of the knee joint during movements such as flexion and extension by preventing excessive anterior or posterior displacement of the femur on the tibia. Proper visualization of the intercondylar eminence ensures an accurate assessment of these critical ligaments, especially in cases of knee trauma or injury.