A macroscopical study of the inferior phrenic artery of female rats, with reference to the embryological background of occurrence of the genital artery from this artery.
The principal aim of this study was to elucidate the general features of the inferior phrenic artery (IPA) of female rats which retain the original embryonic configuration of this artery. The artery of the right side was found to be detached from the renal artery, while that of the left side arose from the aorta. Between these fellow arteries, however, no essential morphological differences were discernible. At some point not far from their origin, they were found to break up into the ascending, suprarenal, suprareno genital and descending arteries. The ascending artery of the right side coursed along with the phrenic nerve, and vascularized a greatest portion of the total area of the partes sternalis et costalis of the diaphragm. Furthermore, the artery was found to be intimately associated with the inferior caval vein. Thus, it could be assumed that this artery of adult rats has been embryologically related to the musculus diaphragmaticus, transverse septum, ventral pleuroperitoneal fold, and the caval venous mesentery. The suprarenal artery took its course along the superior margin of this gland to reach the lateroinferior part of the pars costalis of the diaphragm. Its course and destination strongly indicates that in its development the suprarenal artery has been intimately related to the formation of the ventral pleuroperitoneal fold. The suprarenogenital artery was characterized as giving off a genital branch which entered first the diaphragmogenital ligament, and then took a descending course toward the ovary, in a quite similar manner of origin and course to those of the aberrant gonadal (testicular and gonadal) arteries observed in Japanese human adults (Shinohara et al., 1990; Hanie, to be published). The descending artery was observed to be closely associated with the major splanchnic nerve and the celiac ganglion. The variability of arteries of the IPA of female rats and also of humans, seems to reflect dramatic changes which have occurred in the early stages of development, and have influenced more or less the morphology of the uppermost abdominal anlages of the followings: transverse septum, musculus diaphragmaticus, dorsal and ventral pleuroperitoneal folds, suprarenal gland and celiac ganglion, urogenital organs, inferior caval vein in the caval venous mesentery. In conclusion, it could be said that the anatomy of female rats provide us valuable clues as to the essential configuration of the IPA of humans and the relationships of the IPA to structures which are thought to be directly involved in the development of this artery.
Mizukami
S
S
School of Nursing, Fukui Prefectural College, Japan.
Tanaka
S
S
Moriya
M
M
D000311:Adrenal Glands / Q000098:blood supply; D000818:Animals; D001158:Arteries / Q000033:anatomy & histology / Q000196:embryology; D003964:Diaphragm / Q000098:blood supply*; D005260:Female; D010053:Ovary / Q000098:blood supply*; D051381:Rats; D014599:Uterus / Q000098:blood supply