BLADDER, NORMAL ANATOMY. 



386 



retained for ;i considerable time although it was 

 subjected to pressure, and was afterwards eva- 

 cuated through the urethra when the ligature on 

 the latter was removed. No alteration whatever 

 from the ordinary appearances was observed 

 either during the distension or the subsequent 

 emptying of its cavity, nor did any regurgi- 

 tation take place into the ureters in either 

 state. The same experiment with air instead 

 of water was repeated and with the same effect. 

 It may be further observed that the ductus 

 communis choledochus enters the duodenum in 

 a similar oblique way, that no regurgitation 

 from the intestine ever occurs into it, and yet 

 there is no peculiar muscular fasciculus attached 

 to its orifice which could execute the office 

 ascribed to these lateral boundaries of the tri- 

 gone. To these muscles Sir C. Bell also 

 attributes the projection into the bladder of the 

 third lobe of the prostate gland, usually called 

 the middle or Home's lobe, when this part is in 

 a state of enlargement. There are, however, such 

 plain and simple reasons for this tumour be- 

 coming prominent in this direction rather than 

 in any other, that it is unnecessary to search for 

 an explanation in the action of these muscles, 

 the undoubted development of which in such 

 cases may with a much greater degree of pro- 

 bability be considered as one of the effects and 

 not as the cause of this projection. 



The uvula or apex of the trigone varies very 

 much in its appearance in different persons. 

 In the normal state it is very small, and is 

 most distinctly seen by making only a small 

 opening in the upper region of the bladder 

 when in situ, and looking down towards the 

 cervix ; it then appears as a small projection 

 in the middle line of the orifice of the urethra, 

 which opening it thus assists to close or to fill. 

 It is much effaced by opening the bladder from 

 the urethra after its removal from the subject, 

 the mucous membrane being then easily ex- 

 tended. This projection is only a slight full- 

 ness or prominence of the mucous membrane 

 with an increase in the submucous tissue, in 

 which small follicles or cryptas may be dis- 

 cerned. This part appears rather vascular, and 

 probably possesses some peculiar organization ; 

 the situation also which it holds, as well as its 

 structure, appear to indicate it to be the seat of 

 a proper sensibility, which, when affected, ex- 

 cites the irritability of the whole organ. Many 

 facts which manifest themselves in the treat- 

 ment of urinary diseases seem to corroborate 

 this idea : thus, when a calculus is pressed 

 against this part of the mucous membrane, the 

 pain is insupportable, whereas when it falls or 

 is directed into the inferior fundus, the pain is 

 comparatively trifling; also when a bougie or 

 catheter is being passed into the bladder, a 

 peculiarly acute sensation is experienced as the 

 instrument comes in contact with this par- 

 ticular prominence. The uvula in the child is 

 the most depending part of the bladder, at 

 least in the erect posture ; Ihis is not the case 

 in the adult; hence probably we have in part 

 the reason why calculus is more painful in the 

 former than in the latter. 



The trigone in the female bladder comprises 

 a smaller area, but is broader in proportion 

 than in the male ; it is not so distinct or firm 

 in the former as in the latter, where it is sup- 

 ported not only by a dense substratum, but 

 also by the vasa deferentia, vesieulse seminales, 

 and prostate gland. This portion of the 

 bladder is so firm and incompressible that it is 

 probable the cavity corresponding to it can 

 never be wholly obliterated, so that in the most 

 contracted bladder a few drops of fluid are 

 still retained. The uvula, like other similar 

 portions of the mucous membrane, is subject 

 to infiltration and increase of size in acute in- 

 flammatory affections, as also to chronic and 

 permanent enlargement ; and as it lies nearly 

 over, but a little anterior to the middle lobe 

 of the prostate gland, it is therefore difficult, 

 and in most cases impossible to distinguish 

 affections of the latter from those of the former. 

 The uvula is smaller in the female than in the 

 male; hence the opening from the bladder into 

 the urethra is larger in the former than in the latter. 



Organization of the bladder. a. Arteries.- 

 In the normal slate the bladder is not very 

 vascular ; we have already mentioned that its 

 inner surface is pale and free from any red 

 vessels. The arteries, however, of the bladder 

 are very conspicuous when they have been in- 

 jected ; they are long and tortuous, and are 

 distributed chiefly along the sides, inferior 

 region, and cervix. They are derived from 

 various sources. The internal iliac or hypo- 

 gastric on each side, just before its ligamen- 

 tous termination, sends off one or two vesicul 

 brandies, which ramify on the superior and 

 lateral regions ; the middle hcemorrhoidal and 

 internal pubic also very generally send some 

 considerable branches to its inferior region and 

 cervix; the obturator and epigastric vessels 

 also very frequently send small arteries to it 

 anteriorly. When the bladder is distended, all 

 these vessels are seen very distinctly, and in 

 the muscular coat much more than in the sub- 

 mucous tissue, contrary to what may be ob- 

 served in the other hollow viscera ; this, how- 

 ever, is accounted for by recollecting that the 

 mucous coat of the bladder does not in its 

 normal and healthy condition possess, nor does 

 it indeed require any high degree of organi- 

 zation, as it is simply a reservoir, and has no 

 important function to execute further than to 

 secrete a fine mucous fluid which lubricates its 

 surface and defends it from the irritation of the 

 urine. This secretion mingles with the urine, 

 the properties of which it alters in a remark- 

 able manner whenever it is increased in quan- 

 tity, as occasionally occurs in chronic disease 

 of this organ. The muscular coat of the blad- 

 der is the essential agent in expelling its con- 

 tents, and is therefore more fully supplied with 

 vessels than any other of its tunics. 



b. Veins. The veins of the bladder are 

 large and numerous interiorly, and in old per- 

 sons in particular. There are but few on the 

 superior and lateral regions except towards the 

 inferior part of the latter. In the child the 

 veins are very inconsiderable: this difference 



