384 



BLADDER, NORMAL ANATOMY. 



mal tissue, except perhaps mucous membranes: 

 elasticity exists at the pylorus and at the anus, 

 although true muscular and sphincter fibres are 

 evident at both these outlets. When this region 

 is carefully examined in the male subject, we 

 shall find that immediately behind the pubis, on 

 the anterior and lateral reflections of the pelvic 

 fascia, to these ligaments numerous muscular 

 fibres of the bladder are attached ; these are 

 chiefly longitudinal, but there are also several 

 transverse arched or semilunar, some upon, and 

 others underneath the longitudinal fibres, and 

 with which many of them are continuous. None 

 of these arched fibres pass around or behind the 

 prostate so as to encircle this region. The longi- 

 tudinal, the transverse and decussating or inter- 

 lacing fibres in this situation, are in greater 

 abundance, and may be raised in successive 

 laminae. Veins and nerves are very manifest in 

 and between these; several of the longitudinal 

 fibres of the deeper lamina- pass in so deeply as 

 to approach the mucous surface. When the 

 several strata of longitudinal fibres have been 

 raised from the front and lateral parts of this 

 region, the circular fibres of the bladder become 

 distinct, but do not appear so proportionably 

 increased as were the longitudinal ; but on de- 

 taching more completely the longitudinal strata 

 down to the circumference of the very opening 

 of the urethra, a distinctly fibrous, that is, mus- 

 cular tissue, is evident, bounding this opening 

 laterally and superiorly, but not below. This 

 muscular fasciculus is not intimately connected 

 to the general circular coat ; it appears redder, 

 and of a closer texture, and will be found to be 

 attached to the fibrous or tendinous substance 

 forming the anterior part of the trigone on each 

 side of the uvula, behind which it does not 

 pass. The longitudinal fibres are inserted partly 

 into this semicircular muscle, much in the same 

 manner as the levatores ani are inserted into the 

 circumference of the anus. This structure we 

 consider to be partly elastic, but essentially 

 muscular; it bounds the urelhral opening late- 

 rally and above, but not below; the slight pro- 

 jection of the uvula in the latter situation, and 

 the elasticity and gentle state of contraction 

 natural to all the sphincter muscles, will pre- 

 serve this opening in a constantly closed state 

 during the quiescent and normal condition of 

 the parts. This arrangement is on a level with 

 the uvula, and, of course, behind the orifices of 

 the prostate ducts, although the base of that 

 gland extends further back than this sphincter. 

 We have repeatedly examined beneath the 

 uvula for muscular fibres, but have found none 

 in a transverse direction ; there is, therefore, no 

 portion of a sphincter in that spot, and hence 

 one advantage of the slight elevation caused by 

 the uvula and by that portion of the prostate 

 gland denominated its middle lobe, which cor- 

 responds to it : indeed sphincter fibres in this 

 spot woujd be not only useless, but injurious, as 

 they could scarcely exist without interfering 

 with the ejaculatory ducts. We conceive, then, 

 that the urine is retained in the bladder partly 

 by the relaxed or passive state in which its 

 muscular coats usually remain until they are 

 excited by the sense of distension, partly also 



by the urine, when only in a moderate quantity, 

 gravitating, not towards the neck, but distending 

 the inferior fundus, which lies on a level lower 

 than that of the former, and principally by the 

 dense muscular, elastic, vascular, and nervous 

 tissue which surrounds three-fourths of the 

 orifice of the bladder. The gentle contraction of 

 the latter raises the uvula into the calibre of the 

 opening, while the remaining sides are pressed 

 into contact with it, and thus the bladder is 

 closed. When distension excites the usual feel- 

 ing, the muscular coat contracts, the sphincter 

 relaxes, phenomena exactly corresponding to 

 those which take place under similar circum- 

 stances in the rectum and anus; and as the 

 levatores ani expand the anal opening by draw- 

 ing the sphincter fibres outwards at the time 

 the expulsive powers of the rectum are dis- 

 charging its contents, so the longitudinal fibres 

 of the bladder draw out from the axis of the 

 urethral opening the relaxed sphincter which 

 encompasses three-fourths of it, while the 

 middle band of the posterior longitudinal will 

 plainly depress the uvula and expand the orifice 

 in that aspect, and will even retract and depress 

 the verumontanum, thereby freeing the passage 

 into the urethra, and retracting that sentient 

 caruncle from the irritating influence of the 

 urinary stream. 



The next coat of the bladder, the fourth of 

 some anatomists, or the -second common of 

 others, is the deep cellular, or more properly 

 the submucous cellular coat, by some also de- 

 nominated the nervous tunic. This coat invests 

 the whole organ and connects the muscular and 

 mucous tissues intimately yet loosely ; it con- 

 tains no adipose matter, but is very filamentous, 

 extensible, and elastic: in it are found those 

 vessels and nerves which are to supply the in- 

 ternal surface of the bladder, and which, except 

 in some situations, are not very numerous w lien 

 compared with those in the other hollow vis- 

 cera. This coat, though essentially cellular, pre- 

 sents very many fibrous threads through it, on 

 which much of its strength appears to depend, 

 particularly in those places where the muscular 

 coat is deficient. When the bladder is fully 

 distended, if we dissect off the muscular fibres 

 carefully without injuring this tissue, the mu- 

 cous membrane still remains supported ; but 

 as soon as a portion of this coat is detached, 

 the mucous membrane projects in an unsup- 

 ported sacculated manner. This coat corre- 

 sponds with that elastic tissue in the parietes 

 of the small intestines in some animals, out of 

 which the substance, commonly termed catgut, 

 is formed. 



The third proper coat is the mucous or lining 

 membrane, to expose which the bladder must 

 be opened by a perpendicular incision along 

 its anterior region. This tunic is but a portion 

 of the genito-urinary mucous membrane, and is 

 continuous with that lining the ureters above, 

 and the urethra below. Thevesical portion of this 

 membrane is very thin, has a soft and smooth feel 

 caused by the mucous fluid which lubricates it ; 

 its colour is very pale in the natural condition, 

 although in catarrh or in chronic inflammation 

 it presents a general vascular appearance; but 



