As name indicates, X ray KUB, means x ray of Kidney, ureter, bladder, but the fact is it never gives information about kidney, ureter and bladder most of time. It is taken in standing position so as to see air water level in bowels, some of chest region is covered so as to see gas under diaphragm and to rule out any chest injury means ribs.
However X ray KUB is done so as to see kidney stones, Gall bladder stones, faeces in constipation, air fluid level in intestinal obstruction, to check out the position of stent of ureter or nasogastric tube. It also covers pelvis region so that you can see any stone in bladder and urethra. Now watch out video below on youtube reading an interesting KUB X-Ray.
We have also explained how to see Iliopectineal line, ilioischial line, anterior and posterior rim of acetabulum