_1_, Sacro-coccygeus superior; _2_, sacro-coccygeus lateralis; _3_,
intertransversales; _4_, sacro-coccygeus inferior; _5_,
recto-coceygeus; _6_, sphincter ani externus; _6′_, branch
connecting sphincter ani with constrictor vulvæ; _7_, vestibular
bulb; _8_, tuber ischii; _9_, sacro-sciatic ligament. (After
Schmaltz, Atlas d. Anat. d. Pferdes.)
]
(2) The =middle hæmorrhoidal= or =vesico-prostatic artery= (A.
hæmorrhoidalis media) in the male arises usually near the prostate and
runs backward lateral to the rectum. It supplies branches to the rectum,
bladder, urethra, and accessory genital glands. In the female the
homologous vessel is much larger and gives off the =posterior uterine
artery= (A. uterina caudalis). This runs forward on the side of the
vagina, to which it gives branches, and ramifies on the body of the
uterus, anastomosing with the anterior and middle uterine arteries. (In
some cases this artery arises from the internal iliac or the umbilical.)
(3) The =perineal artery= (A. perinei) is relatively small in the male.
It passes upward at the side of the anus, which it supplies, and gives
twigs to the bulbo-cavernosus muscle and the skin of the perineum. In
the female it is large and is distributed to the anus and vulva, and
gives a large branch to the vestibular bulb.
(4) The =artery of the bulb= (A. bulbi urethræ) may be regarded as the
direct continuation of the internal pudic in the male. It lies at the
side of the urethra above the ischial arch, dips under the
bulbo-cavernosus muscle, and ramifies in the corpus spongiosum. Before
doing so it gives off a small branch which turns around the ischial arch
to reach the dorsum penis, and anastomoses with the deep branch of the
obturator.
(4_a_) The =artery of the clitoris= (A. clitoridis) is the homologue in
the female of the preceding vessel, but is much smaller. It passes to
the ventral surface of the vulva with the internal pudic nerve, supplies
the clitoris, and gives twigs to the vulva.
[Illustration: