The =external iliac artery= (A. iliaca externa) arises from the aorta
under the fifth lumbar vertebra, usually just in front of the origin of
the internal iliac. It descends at the side of the pelvic inlet along
the tendon of the psoas minor, crosses the insertion of that muscle, and
reaches the level of the anterior border of the pubis, where it becomes
the femoral artery. It is covered by the peritoneum and fascia, and is
related behind to the corresponding vein. Its branches are as follows:
1. The =circumflex iliac artery= (A. circumflexa ilium profunda) arises
from the external iliac at its origin or from the aorta directly. It
passes across the iliac fascia toward the external angle of the ilium,
near which it divides into two branches. The artery lies between the
fascia and the peritoneum and is accompanied by two veins and the
external cutaneous nerve of the thigh. The =anterior branch= gives twigs
to the iliacus and psoas muscles, and passes downward and forward in the
flank between the obliquus internus and transversus abdominis, in which
it ramifies. The =posterior branch= perforates the abdominal wall and
runs downward on the inner face of the tensor fasciæ latæ to the fold of
the flank, supplying branches to that muscle, the panniculus, the
precrural lymph glands, and the skin.
2. The =cremasteric artery= (A. spermatica externa) is a very small
vessel which arises in a variable manner. It springs most often from the
external iliac near its origin, but may come from the circumflex iliac,
the aorta between the external and internal iliac, or the latter vessel.
It accompanies the cremaster muscle to the inguinal canal, supplies
twigs to that muscle, the tunica vaginalis, and other constituents of
the spermatic cord (Fig. 450).
2_a_. The =middle uterine artery= (A. uterina media) of the female is
regarded as the homologue of the preceding vessel. It has a similar
origin, but is a much larger artery, which passes between the layers of
the broad ligament and reaches the horn of the uterus close to its
junction with the body. It is distributed to both, and anastomoses with
the anterior and posterior uterine arteries.