We present detailed anatomic findings on collecting system anatomy and
renal morphometry in the pig and compare these findings with previous
findings in humans. We studied three-dimensional polyester resin corr
osion endocasts of the pelviocaliceal system obtained from 100 kidneys
(50 pigs). Eighty kidneys were evaluated morphometrically, considerin
g length, cranial pole width, caudal pole width, thickness, and weight
. The pig collecting system was classified into two major groups (A an
d B). Group A (40%) was composed of kidneys in which the mid-zone is d
rained by calices dependent on the cranial or the caudal caliceal grou
p or both. Group B (60%) kidneys have the mid-zone drained by calices
independent of the polar groups, Group B includes two subtypes (B-I an
d B-II). The pig collecting system showed only angles smaller than 90
degrees between the caudal (lower) infundibulum and the renal pelvis.
Renal morphometric measurements revealed the following means: length 1
1.8 cm, cranial pole width 5.64 cm, caudal pole width 5.35 cm, thickne
ss 2.76 cm, and weight 98 g. As in human kidneys, one may group the pi
g collecting system into two groups. Nevertheless, in pigs, we did not
find a subdivision of Group A. The incidence of collecting systems in
Groups A and B and the subtypes of Group B in pigs are different from
those in humans. Also different from humans, in pigs, we found only a
ngles smaller than 90 degrees between the caudal (lower) infundibulum
and the renal pelvis. Except for the length, the means of the other mo
rphometric measurements of the pig kidney are smaller than those of hu
mans. From an anatomic standpoint, despite the differences pointed out
, we conclude that the pig kidney is a good animal model for endourolo
gic research and training.