THE BLADDER. 1905 



borders. On each side the serous covering passes from the organ to line the para- 

 vesical fossa, the sickle-shaped depression that separates the contracted bladder from 

 the adjacent pelvic wall. In front these side folds, the lateral false ligaments, meet 

 at the vesical apex, where they cover the fibrous band of the urachus and are reflected 

 onto the anterior abdominal wall as the anterior false ligament (ligamentum umbilicale 

 medium). An uncertain fold, the plica vesicalis transversa, often crosses the other- 

 wise smooth upper surface of the bladder. This peritoneal ridge, sometimes repre- 

 sented by two or more low wrinkles, extends laterally to be lost either on the pelvic 

 wall or, passing over the pelvic brim, towards the internal abdominal ring. Dixon ' 

 found the fold well represented in the male foetus, and inclines to the view that its 

 production is connected with a drag on the peritoneum incident to the formation of 

 the inguinal pouches. Behind the peritoneum passes from the posterior border of 

 the empty bladder over the upper end of the seminal vesicles and the vasa deferentia, 

 to form a horizontal crescentic shelf-like fold (plica rectovesicalis ) from 1-1.5 cm. 

 wide, that extends from the bladder backward, embracing the rectum and ending at 

 the sacrum on either side of the gut (Fig. 1619). 



Since this duplicature includes parts of the seminal ducts and vesicles, Dixon and Birming-- 

 ham' have suggested for its lateral and backward extensions, which contain bundles of invol- 

 untary muscle (m. rectovesicalis) attached to the sacrum and rectum, the appropriate name, 

 sacro-genital folds, and pointed out their correspondence to the utero-sacral folds in the female 

 (page 2007). The median part of the shelf-like plica, conspicuous behind the emptj- bladder, 

 but more or less obliterated on the distended organ, overhangs the lowest part of the peritoneal 

 recess, the recto-vesical fossa, that intervenes between the rectum and the seminal vesicles and 

 ampullae of the vasa deferentia, and towards which the fundus of the bladder is directed. In 

 recognition of these relations, the anterior wall of this recess being in direct relation with the 

 seminal tracts, the authors last mentioned propose to call this depression the recto-genital fossa, 

 — a term alike applicable to both sexes, since the relations of the rectum to the uterus in the 

 pouch of Douglas in the female are similar. All other parts of the bladder, including the 

 postero-inferior (fundus) and the antero-inferior surfaces, are entirely devoid of peritoneal 

 covering. In the female the serous membrane passes from the posterior border of the bladder 

 onto the anterior uterine wall, the shallow utero-vesical fossa intervening. Occasionally a corre • 

 sponding depression exists in the male as a slight indentation between the posterior vesical wull 

 and the seminal vesicles (Dixon). 



With the changes of form and position which the bladder undergoes when it becomeo dis- 

 tended are associated alterations in its peritoneal relations. These include the gradual obliter- 

 ation of the upper part of the recto-vesical fossa, along with the shelf-like fold, and the elevation 

 of the line of peritoneal reflection at the sides, so that the lateral false ligaments no longer reach 

 the pelvic floor, but pass from the lateral wall of the pelvis directly to the superior surface of the 

 bladder, from which the plica transversa has disappeared. Anteriorly the relations of the serous 

 covering are also affected, since with the rise of the bladder above the level of the symphysis 

 the peritoneum is carried upward and a suprapubic non-peritoneal area becomes progressively 

 more extensive until, in extreme distention, a space measuring vertically from 8-9 cm., or about 

 3X in-, niay be uncovered. 



Fixation. — The attachments of an organ so subject to considerable alterations 

 in size and form as is the bladder must ob\nously provide for such changes as well 

 as the maintenance of a more or less definite position. The ' ' ligaments ' ' of the 

 bladder are conventionally described as true and false, under the latter being included 

 the peritoneal folds (above described) that pass from the organ to the adjacent ab- 

 dominal and pelvic walls. The sacro-genital folds were formerly sometimes called 

 the posterior false ligaments. From the manifest instability of the relations and 

 attachments of the peritoneum incident to distention and contraction, it is evident that 

 such peritoneal folds can contribute litde to the definite support or fixation of the 

 bladder ; hence those parts of the organ possessing a serous covering are movable. 

 The inferior surface, on the contrary, is comparatively fixed on account of its close 

 relations to the pelvic floor (and in the male to the prostate) and the presence of 

 fascial bands or true ligaments. The latter are derived from the pelvic fascia, which 

 in the vicinity of the bladder presents a stout, glistening, band-like thickening (arcus 

 tendineus) that on each side stretches from the posterior surface of the symphysis, a 



^ Journal of Anatomy and Physiolog\', vol. xxxiv., 1900. 

 2 Journal of Anatomy and Physiology, vol. xxxvi.| 1902. 



120 



