el against the bone, causing its curve to be greater than if the
bladder were empty and collapsed. This fact requires to be borne in
mind, for, in order to introduce a bougie, or to allow a large injection
to pass with freedom into the bowel, the bladder should be first
evacuated. The coccygeal bones, Q, continuing in the curve of the
sacrum, bear the rectum, W, forwards against the base of the bladder,
and give to this part a degree of obliquity upwards and backwards, in
respect to the perinaeum and anus. From the point where the prostate, V,
lies in contact with the rectum, W, this latter curves downwards, and
slightly backwards, to the anus, P. The prostate is situated at a
distance of about an inch and a half or two inches from the anus--the
distance varying according to whether the bladder and bowel be distended
or not. [Footnote]

[Footnote: The distance between any two given parts is found to vary in
different cases. "In subjects of an advanced age," Mr. Stanley remarks,
"a deep perinaeum, as it is termed, is frequently met with. This may be
occasioned either by an unusual quantity of fat in the perinaeum, or by
an enlarged prostate, or by the dilatation of that part of the rectum
which is contiguous to the prostate and bladder. Under either of these
circumstances, the prostate and bladder become situated higher in the
pelvis than naturally, and consequently at a greater distance from the
perinaeum."--On the Lateral Operation of Lithotomy.]

The arteries of the bladder are derived from the branches of the
internal iliac, S. The rectum receives its arteries from the inferior
mesenteric and pudic. The veins which course upwards from the rectum are
large and numerous, and devoid of valves. When these veins become
varicose, owing to a stagnation of their circulation, produced from
whatever cause, the bowel is liable to be affected with haemorrhoids or
to assume a haemorrhagic tendency.

The pudic artery, S s, is a branch of the internal iliac. It passes from
the pelvis by the great sciatic foramen, below the pyriformis muscle,
and in company with the sciatic artery. The pudic artery and vein wind
around the spine, E, of the ischium, where they are joined by the pudic
nerve, derived from, T, the sacral plexus. The artery, in company with
the nerve and vein, re-enters the pelvis by the small sciatic foramen,
and gets under cover of a dense fibrous membrane (obturator fascia),
between which and the obturator muscle, i