istic to the abdomen and thorax, when by an
injury to the cord in the sacral spine the perinaeal apparatus alone
becomes paralysed, its relaxation allows the thoracic and abdominal
force to evacuate the pelvic organs involuntarily. It would appear,
therefore, that the term "paralysis" of the bladder or rectum, when
following spinal injuries, &c. &c. means, or should mean, only a
paralytic state of the abdomino-pelvic muscular apparatus, entirely or
in part. For, in fact, neither the bladder nor rectum ever acts
voluntarily per se any more than the stomach does, and therefore the
name "detrusor" urinae, as applied to the muscular coat investing the
bladder, is as much a misnomer (if it be meant that the act of voiding
the organ at will be dependent upon it) as would be the name "detrusor"
applied to the muscular coat of the stomach, under the meaning that this
were the agent in the spasmodic effort of vomiting.

The urinary bladder, G, Plate 49, (in the adult body,) occupies the true
pelvic region when the organ is collapsed, or only partly distended. It
is situated behind the pubic symphysis and in front of the rectum,
C,--the latter lies between it and the sacrum, A. In early infancy, when
the pelvis is comparatively small, the bladder is situated in the
hypogastric region, with its summit pointing towards the umbilicus; as
the bladder varies in shape, according to whether it be empty or full,
its relations to neighbouring parts, especially to those in connexion
with its summit, vary also considerably. When empty, the back and upper
surface of the bladder collapse against its forepart, and in this state
the organ lies flattened against the pubic symphysis. Whether the
bladder be distended or not, the small intestines lie in contact with
its upper surface, and compress it in the manner of a soft elastic
cushion. When distended largely, its summit is raised above the pubic
symphysis, the small intestines having yielded place to it, and in this
state it can be felt by the hand laid upon the hypogastrium.

The shape of the bladder varies in different individuals. In some it is
rounded, in others pyriform, in others peaked towards its summit. Its
capacity varies also considerably at different ages and in different
sexes. When distended, its long axis will be found to coincide with a
line passing from a point midway between the navel and pubes to the
point of the coccyx, the obliquity of this direction being greatest when
t