- URINAL' SYSTEiAl. 281 



The cervix is the small, circular, posterior part of the bladder. 

 It has a light-pinkish hue, and is comparatively thick and sub- 

 stantial to the feel. The triangular ligament attaches it to the 

 pubes, and it is continuous at the posterior end with the urethra. 



Structure. — The bladder has three coats : an external one, 

 which is derived from the peritoneum ; a mucous membrane, to 

 which it mainly owes its integrity and consistence ; and a dif- 

 fuse fibrous texture interposed between the two, which is of a 

 muscular nature. The peritoneal coat, which forms but a |)ar- 

 tial covering, is smooth, polished, and moistened with serous 

 exudation externally ; but found rough and pilous internally, when 

 torn from its adhesions with the muscular: in a word, it in 

 nowise differs in its properties from the peritoneal tunics of the 

 abdominal viscera in general. It serves to hold the bladder in 

 its proper place and position, and to a certain degree to counter- 

 act preternatural distention. 



'J'he muscnlar coat, though it may be demonstrated through 

 the pellucid peritoneum, is brought more distinctly into view by 

 stripping off that membrane, to which it is closely and firmly 

 attached by fine cellular tissue. Pale fasciculi are then seen 

 running irregularly in a longitudinal manner; and, underneath 

 them, others which are smaller, taking an equally iiregular 

 course in the circular direction: in the empty or half-distended 

 state of the organ, however, both these orders of fibres assume 

 spiral courses ; which enables them to bear considerable exten- 

 sion without the risk of rupture, while their cellular connexions, 

 being loose, admit of their being drawn apart with equal facility. 

 The longitudinal fasciculi are thickest about the fundus, where 

 they all converge to its central point ; the circular are strongest 

 around the cervix : the former exert a special contraction in 

 forcing the urine towards the neck, constituting what has been 

 called the detrusor uriuce; the latter, which are mingled with 

 cellular tissue and some small veins, giving them the feel of 

 greater substance than they really possess, form the sphincter 

 vesiccE of those who (with no more reason in my opinion) make a 

 separate muscle of this part. By the simultaneous contraction 

 of both orders of fibres the parietes of the bladder may be drawn 

 towards one common centre, so as to diminish its capacity 

 gradually in every part, until the cavity is even altogether 

 annihilated. 



The mucous coat shews itself exteriorly in the interspaces be- 

 tween the fasciculi of the muscular, covered only by the inter- 

 posed cellular tissue which serves as the conmion uniting me- 

 dium of all three tunics. While the bladder remains empty, the 

 contractions of the muscular coat throw this one into riigce, and 

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