Area cribrosa in the medullary papilla is seen together with minor calyx. Minor calyx is the subdivision of a major calyx in the pelvis of the kidney. The minor calyx is an infolded tube forming a double-walled cup. The inner wall of the calyx fits over the papilla of a pyramid. Area cribrosa are the sieve-like appearance of the papilla which is produced by the large number of collecting tubules passing through it.