In the PA tangential projection (Hughston method) of the patella, how many degrees should the knee be flexed?

• A. 30°
• B. 45°
• C. 60°
• D. 90°

Answer: (B)

In the PA tangential projection of the patella utilizing the Hughston method, the knee should be flexed at an angle of 45 degrees. This degree of flexion allows for optimal visualization of the patellofemoral joint by placing the patella in a position that maximally separates it from the femur. The 45-degree flexion provides a clear view of any potential abnormalities or pathologies associated with the patella, such as fractures or dislocations.

Moreover, this angle aligns the patella appropriately in relation to the x-ray beam, enhancing the clarity of the images obtained. It is important for radiographers to adhere to this specific degree of flexion to ensure accurate diagnostic information is captured.

In contrast, other angles such as 30 degrees or 60 degrees would not provide the same level of detail or could even obscure critical anatomical relationships. A 90-degree flexion might overly compress the joint and lose important visualization of the patella in relation to the femur, thus compromising the diagnostic quality of the image.