Question

What is the rationale for positioning the hand in supination for the AP projection of the forearm?

a) To demonstrate the scaphoid without superimposition
b) To align the metacarpals parallel to the IR
c) To prevent foreshortening of the radius and ulna
d) To show the carpal bones in a lateral profile

Answer 1

Positioning the hand in supination during an AP projection of the forearm prevents foreshortening of the radius and ulna by ensuring they are parallel to the imaging receptor.

Step-by-step explanation:

The rationale for positioning the hand in supination for the AP (anterior-posterior) projection of the forearm is to prevent foreshortening of the radius and ulna. When in supination, the bones of the forearm, namely the radius and ulna, are aligned parallel to each other and to the imaging receptor (IR). This positioning ensures that the bones are accurately represented on the radiograph without overlapping or distortion, which would obscure diagnostic details. This is distinct from other projections which may focus on different anatomical structures like the carpal bones or the scaphoid.