An experimental study of the anatomy of the tubules of the human kidney and its relation to calculus formation.

During a period of 28 years 6 clinical observations concerning humans and a dog indicated that micro-calculi can form and acquire laminated growth at the base of the papillae in the renal medulla. In the subsequent research, plastic casts were made of the distal tubules of human post mortem kidneys. Study of these showed that acute angle and Z-bends were more prevalent at the bases of the papillae in the lower calices. Macro-photographs revealed that kinks in the wall of the tubule can reduce the lumen at these points. The combined evidence suggests that crystals and cellular debris may become impacted at these sites and form the nucleus of a stone.