What tube angle is recommended for AP projection of the fifth digit when joint spaces are of concern?

What tube angle is recommended for AP projection of the fifth digit when joint spaces are of concern?

• A. 0 degrees
• B. 15 degrees cephalic
• C. 15 degrees caudal
• D. 30 degrees cephalic

Answer: (B)

To visualize the joint spaces in the AP view of the fifth digit, a slight tilt of the x-ray tube toward the head helps separate the joints and reduce bone superimposition. A 15-degree cephalad angle aligns the beam with the plane of the finger joints, improving visibility of the distal interphalangeal and metacarpophalangeal joints without introducing excessive distortion. Zero degrees often leads to overlapping joints, while a caudal tilt or a much larger cephalad angle can worsen overlap or distort the anatomy. So, 15 degrees cephalad is the best choice for this scenario.

To visualize the joint spaces in the AP view of the fifth digit, a slight tilt of the x-ray tube toward the head helps separate the joints and reduce bone superimposition. A 15-degree cephalad angle aligns the beam with the plane of the finger joints, improving visibility of the distal interphalangeal and metacarpophalangeal joints without introducing excessive distortion. Zero degrees often leads to overlapping joints, while a caudal tilt or a much larger cephalad angle can worsen overlap or distort the anatomy. So, 15 degrees cephalad is the best choice for this scenario.