When performing an AP axial projection of the foot, the central ray is directed ____.

In the AP axial projection of the foot, it is crucial to direct the central ray correctly to achieve optimal visualization of the foot's anatomy. The correct technique involves angling the central ray towards the heel. Specifically, a 10° angle enhances the open joint spaces necessary for accurate diagnosis and assessment.

By directing the central ray toward the heel, the projection minimizes superimposition of the toes over the forefoot, ensuring that critical structures such as the metatarsals and tarsals are well delineated. This oblique angling helps to project the foot's anatomy more clearly, facilitating better image quality.

The other choices reflect angles that do not align with the standard practice for the AP axial projection of the foot. For instance, an angle away from the heel or toward the toes would not provide the appropriate visualization. Therefore, the practice of angling the central ray to the heel by 10° is fundamental for producing a diagnostic-quality image in this specific projection.