81 
ABDOMINAL VISCERA OF THE HORSE. 
loped by peritoneum, and constitutes the anterior false ligament. 
The peritoneum coming off from the rectum on to the superior 
surface of the bladder, gives rise to a pouch termed the recto¬ 
vesical pouch, or cul de sac, and laterally to the triangular folds 
limiting the latter, known as the superior false ligaments. Behind 
the peritoneal reflection, the bladder is attached to the rectum 
and pelvic parietes by a continuation of the pelvic fascise, 
which, leaving the inferior surface of the pelvis at the sym¬ 
phisis pubis, comes on to the bladder, forming the inferior true 
ligaments of the latter ; the fascia is then continuous on to the 
rectum, blending with the cellular coat. The pelvic fascia is 
also traced on to the prostate and sides of the bladder from the 
posterior part of the obturator foramen, constitutingjhe'lateral 
true ligaments. 
Beneath this fibro-serous coat are muscular fibres arranged in 
a peculiar manner. There is an outer longitudinal set traceable 
from the cervix forwards towards the body, where the fibres 
diverge and become oblique, and some even circular; this layer is 
principally developed posteriorly. The inner or circular layer is 
not arranged in concentric rings; but its fibres, beginning at the 
fundus, appear to arise from various centres on the surface, 
and to be taking a direction more or less curved in different parts, 
so as to get transversely to the long axis of the viscus, and thus 
from the inner side have a circular appearance. These fibres 
are more decidedly circular at the neck, and act somewhat like 
a sphincter. Some of the deeper fibres at the neck of the 
bladder extend forwards to each orifice of the ureter, marking 
the limit of the vesical trigon, whose office must be that of ap¬ 
proaching the lips of the elliptical apertures. 
The mucous coat of the bladder is generally more or less 
coated with mucus and epithelium, which guard the structure 
from the corroding effects of the secretion it has to come in con¬ 
tact with. It is thrown into numerous folds, taking various 
directions, but principally concentrical towards the fundus, and 
longitudinal at the cervix, all of which are effaceable by dis¬ 
tention of the bladder, and are most prominent when the latter 
is collapsed. At the upper part of the urethral orifice of the 
bladder the mucous lining is smooth and free from folds, mark¬ 
ing out a triangular space, bounded anteriorly by a line drawn 
between the orifices of the ureters, and laterally by two lines 
meeting at a spot at the superior part of the vesical orifice. 
This is termed the vesical trigon. At its apex is a projecting 
fold of mucous membrane or uvula vesicse, which seems to 
moderate the flow of urine into the urethra. 
The bladder is supplied with blood from the internal pudicj 
and its veins empty into the internal pudic vein. 
VOL. XXV. M 
