URINARY BLADDER. 



Harrison, are " inserted anteriorly and laterally into the 

 cellulo-vascular and glandular tissue around the cervix, 

 and posteriorly into a more dense tissue connecting the 

 urethra to the vagina." 



The circular fibres are found to be scattered, pale, and 

 indistinct on the upper portions of the bladder, while on 

 the lower and about the neck they become more distinct 

 and close, and form what is considered by some a distinct 

 muscle, called the sphincter vesicce. There are a variety of 

 opinions in reference to this sphincter muscle ; some, with 

 Mr. Guthrie, asserting that there are no fibres around the 

 neck of the bladder capable of forming a sphincter, while 

 others, as Mr. Bell, Harrison, and Homer, distinctly de- 

 scribe them. 



Sir Charles Bell represents a plane of muscular fibres, 

 forming a semicircular band, about an inch in breadth, sur- 

 rounding the lower half of the orifice of the urethra, and 

 at this point especially strong, and dispersing into the 

 substance of the bladder ; while the upper half of the orifice 

 is surrounded by a weaker set of fibres, though continuous 

 with the lower, thus completing the sphincter. 



Homer speaks of a similar muscular band on the lower 

 semi-circumference of the neck of the bladder, the fibres of 

 which, however, he finds not to run into the ordinary mus- 

 cular structure of the bladder, but to go transversely and 

 be connected with the lateral lobes of the prostate ; while 

 the superior semi-circumference presents a broad, thin, 

 muscular layer, which is lost in the muscular structure of 

 the bladder. 



Beneath the mucous membrane of the vesical triangle, 

 this same anatomist describes a muscular structure of the 

 same extent and shape as the triangle itself. The anterior 

 angle he traces to the posterior part of the caput gallina- 

 ginis. Between the two ureters, says Mr. Harrison, the 

 circular or transverse fibres are very distinct, and a semi- 

 lunar band forms the base of the trigone. Muscular fibres 

 are also traced around and upon the ureters. 



The third set of muscular fibres, from their honey-comb 



