title: [Morphological studies on the renal papillae of the kidney in Japanese adults].
abstract: In the present study, 55 kidneys were obtained from 29 Japanese adults, sectioned frontally to expose their renal papillae, and were macroscopically observed. The average number of papillae per kidney was 12.87 +/- 3.09 (7 to 22); no differences by sex or laterality were found. The number of papillae was positively correlated with the number of minor calices (p < 0.01) and renal weight (p < 0.05). However, there was no correlation with the number of papillae and age. Additionally, a positive correlation was found between renal weight and the number of minor calices (p < 0.05). Based upon the number of the renal papillae in each renal calyx, the papillae were divided into "simple" and "complex" groups. The number of papillae in the complex group was 2 (bifid), 3 (trifid), or 4 (cruciate). These papillae were further grouped into two types, "separate" or "fused." Therefore, the papillae were classified into 7 types such as simple, bifid separate, bifid fused, trifid separate, trifid fused, cruciate separate, and cruciate fused. The appearance ratio of the above 7 types of papillae were as follow: simple (51.7%), bifid fused (23.4%), trifid fused (14.3%), bifid separate (6.0%), cruciate fused (4.1%), trifid separate (0.2%), and cruciate separate (0.2%). The number of simple papillae (214, 51.7%) was approximately the same as that of total complex papillae (200, 48.3%). In the complex group, the number of separate papillae (27, 13.5%) was quite fewer than that of fused papillae (173, 86.5%). The original papillae had the shape of a flat cone. The average long length of the bases of papillae were 6.7 mm in simple papilla, 10.3 mm in bifid fused papilla, 11.0 mm in bifid separate papilla, 11.9 mm in trifid fused papilla, and 13.7 mm in cruciate fused papilla. The more the number of papilla increases, the more the length of the bases of papilla becomes long. However, the short length of the bases and height in each papillae were not different. Simple and bifid papillae were mostly observed in the hilus, whereas trifid and cruciate were frequently found in the cranial part of the kidneys.
authors.affiliation: Second Department of Anatomy, Nippon Medical School, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Habara
authors.forename: M
authors.initials: M
authors.lastname: Asakawa
authors.forename: H
authors.initials: H
authors.lastname: Ito
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D044466:Asian People; D005260:Female; D006801:Humans; D007564:Japan; D007679:Kidney Medulla / Q000033:anatomy & histology*; D008297:Male; D008875:Middle Aged