Which of the following describes the correct part positioning for a lateral hand x-ray?

In a lateral hand x-ray, the correct positioning involves aligning the hand on its ulnar surface, ensuring that the 5th digit (the little finger) is aligned with the ulna. This positioning is essential because it allows for a clear imaging of the hand's skeletal structures from a lateral perspective, providing the necessary contrast and detail for accurate diagnosis.

By placing the hand in this manner, the bony anatomy of the wrist, hand, and fingers is better visualized, which is vital for evaluating fractures, dislocations, or other pathologies. Positioning the hand in this way also minimizes superimposition of the phalanges and allows the radiologist to assess each finger and its relationship to the wrist and forearm accurately.

The other options do not achieve the optimal positioning needed for a lateral view. For example, placing the hand palm down or flat without rotation could obscure important details and lead to an inaccurate interpretation of the x-ray images. Similarly, bending the wrist and curling the fingers could create overlapping shadows in the imaging, hindering clarity. Thus, the proper alignment on the ulnar surface with the 5th digit in line with the ulna is crucial for obtaining a quality lateral hand x-ray.