82 URINARY GROANS. 



forming a close compact tissue, which has the effect of a parti* 

 cular apparatus for retaining, the urine, and is called Muscu- 

 lus Sphincter Vesicas UrinariEe. Generally, anatomists have 

 not considered this structure as distinct from the muscular coat 

 at large; but Sir Charles Bell, now a Professor in the University 

 of Edinburgh, whose reputation as an anatomist is well esta- 

 blished, gives the following account of it: 



" Begin the dissection by taking off the inner membrane of 

 the bladder from around the orifice of the urethra. A set of 

 fibres will be discovered, on the lower half of the orifice, which, 

 being carefully dissected, will be found to run in a semicircular 

 form round the urethra. These fibres make a band of about 

 half an inch in breadth, particularly strong on the lower part 

 of the opening, and, having mounted a little above the orifice, 

 on each side, they dispose of a portion of their fibres in the 

 substance of the bladder. A smaller and somewhat weaker 

 set of fibres will be seen to complete their course, surrounding 

 the orifice on the upper part; to these sphincter fibres a bridle 

 is joined, which comes from the union of the muscles of the 

 ureters."* 



After repeated observations on this point, I have come to the 

 conclusion that Mr. Bell has indicated a real structure; but my 

 own dissections have resulted as follows: The inferior semi- 

 circumference of the neck of the bladder is surrounded by a 

 thick fasciculus of muscular fibre, half an inch wide, running 

 in a transverse direction, and having its ends attached to the 

 lateral lobes of the Prostate Gland, being above the third lobe 

 of the latter. This fasciculus is perfectly distinct from the or- 

 dinary muscular fibre of the bladder, and resembles in its tex- 

 ture the musculo-fibrous coat of the arteries. The superior se- 

 micircumference is also surrounded by a thin layer of muscular 

 fibres of an ordinary kind, forming a broad, thin band of a cre- 

 scentic shape, the lower ends of which are insensibly lost in the 

 adjacent muscular coat of the bladder by being spread out. And, 

 lastly, beneath the mucous membrane of the vesical triangle there 

 is a triangular muscle of the same size as the vesical triangle. 

 Having elongated angles, the anterior angle may be traced to 

 the posterior part of the caput gallinaginis, and the posterior 



* Diseases of the Urethra, &c., p. 10. Lond. 1820. * 



