THE STUDY ON ANATOMICAL STRUCTURE IN THE URETEROVESICAL JUNCTION

Abstract

As a result of examination of the anatomical structure of ureterovesical junction in sixteen normal bladder specimens by microdissection and histological method, the following views were obtained:
1) Intravesical ureter is formed to be oppressed by longitudinal muscle fibers of the posterior side of the bladder.
2) The ureter from 1-2cm upper side than ureteral hiatus to intramural segment is almost surrounded by the periureteral sheath running parallel to the strike. This periureteral sheath consists mainly of the longitudinal muscle fibers of the bladder and partly of the circular muscle fibers and collagen fibers. Accordingly, it is considered that the periureteral sheath has developed from the bladder.
3) On the roof and fundus of the Intravesical ureter, there exist thick circular and longitudinal muscle fibers running at right angles to the ureters, by which the ureter is oppressed upon extending and contracting of the bladder.
4) Although the ureteral muscle fibers are not stratified but reticulated at the extravesical portion, these fibers clearly run at the intravesical portion longitudinally. After the ureteral muscle fibers expand like a fan at the portion passing the ureteral orifice and from each side partly cross to form the superficial trigonal layer, almost all parts of these fibers reach the verumontanum but partially terminate under mucosa of the trigone.
5) Most of the superficial trigonal layer is consisted of the ureteral muscle fibers partially including the vesical detrusor muscle fibers.
6) There exist the vesical circular muscle fibers under the superficial trigonal layer. These vesical circular muscle fibers partly cross to the longitudinal muscle fibers of the deeper layer and reticulate. Some fibers run into the periureteral sheath.
7) The longitudinal muscle and circular muscle of the bladder are not separate and cannot be distinguished as outer and middle layers, but a continuity between them is witnessed.
According to these views, as to the role of UVJ for VUR prevention, I have reached the conclusion that VUR shall be prevented by wringing and oppression of the intravesical ureter by the tension and contraction of the vesical detrusor muscle, enlargement of the intravesical ureter and the reduction of cavity by the tension and contraction of the trigone, and the reduction of the ureteral cavity by the periureteral sheath.