"AP foot, the thick portion of the wedge over the distal aspect of the foot"
"Compensating filters are external, uniquely shaped; typically aluminium mounts often affixed to the collimator of the x-ray tube. The filters are used to limit the primary beam at an anatomical region during a specific examination that requires fine radiographic detail at both the 'denser' and 'less dense' regions, e.g. a horizontal beam lateral hip requiring detail at both the proximal and distal portion of the image."