BLADDER. 797 



The false ligaments of the bladder are, two posterior, two lateral, and one 

 superior. 



The two posterior pass forwards, in the male, from the sides of the rectum ; in 

 the female, from the sides of the uterus, to the posterior and lateral aspect of 

 the bladder ; they form the lateral boundaries of the recto-vesical fold of peri- 

 toneum, and contain the obliterated hypogastric arteries, and the ureters, beside 

 vessels and nerves. 



The two lateral ligaments are reflections of the peritoneum, from the iliac 

 fossae to the sides of the bladder. 



The superior ligament is the prominent fold of peritoneum extending from the 

 summit of the bladder to the umbilicus. It covers the urachus, and the oblite- 

 rated hypogastric arteries. 



Structure. The bladder is composed of four coats : a serous, a muscular, a 

 cellular, and a mucous coat. 



The serous coat is partial, and derived from the peritoneum. It invests the 

 posterior surface, from opposite the termination of the two ureters to its sum- 

 mit, and is reflected from this point and from the sides, on to the abdominal and 

 pelvic walls. 



The muscular coat consists of two layers of unstriped muscular fibre, an 

 external layer, composed of longitudinal fibres, and an internal layer of circular 

 fibres. 



The longitudinal fibres are most distinct on the anterior and posterior sur- 

 faces of the organ. They arise in front, from the anterior ligaments of the 

 bladder, from the neck of the bladder, and, in the male, from the adjacent por- 

 tion of the prostate gland. They spread out, and form a plexiform mesh, on 

 the anterior surface of the bladder, being continued over the posterior surface 

 and base of the organ to the neck, where they are inserted into the prostate, in 

 the male, and into the vagina in the female. 



Other longitudinal fibres arise, in the male, from the sides of the prostate, 

 and spread out upon the sides of the bladder, intersecting with one another. 



The circular fibres are very thinly and irregularly scattered on the body of 

 the organ ; but, towards its lower part, round the cervix and commencement 

 of the urethra, they are disposed as a thick circular layer, forming the sphincter 

 vesicre, which is continuous with the muscular fibres of the prostate gland. 



Two bands of oblique fibres, originating behind the orifices of the ureters, 

 converge to the back part of the prostate gland, and are inserted, by means of 

 a fibrous process, into the middle lobe of that organ. They are the muscles of 

 the ureters, described by Sir C. Bell, who supposed that, during the contraction 

 of the bladder, they served to retain the oblique -direction of the ureters, and 

 so prevent the reflux of urine into them. 



The cellular coat consists of a layer of areolar tissue, connecting together the 

 muscular and mucous coats, and intimately united to the latter. 



The mucous coat is thin, smooth, and of a pale rose color. It is continuous 

 through the ureters with the lining membrane of the uriniferous tubes, and 

 below, with that of the urethra. It is connected loosely to the muscular coat, 

 by a layer of areolar tissue, excepting at the trigone, where its adhesion is 

 more close. It is provided with a few mucous follicles ; and numerous small 

 racemose glands, lined with columnar epithelium, exist near the neck of the 

 organ. The epithelium covering it is intermediate in form between the columnar 

 and squamous varieties. 



Interior of the bladder. Upon the inner surface of the base of the bladder, 

 immediately behind the urethral orifice, is a triangular, smooth surface, the apex 

 of which is directed forwards ; this is the trigonum vesicse, or trigone vesicale. 

 It is paler in color than the rest of the mucous membrane, and never presents 

 any rugaB, even in the collapsed condition of the organ, owing to its intimate 

 adhesion to the subjacent tissues. It is bounded on each side by two slight 

 ridges, which pass backwards and outwards to the orifices of the ureters, and 



