Neurovasculature of the Pelvis
Arterial supply of the pelvis
Several centimeters after the abdominal aorta bifurcates into the right and left common
iliac arteries, the common iliac artery further bifurcates into the internal iliac artery and the
external iliac artery.
As the external iliac artery passes inferiorly and posteriorly to the inguinal ligament and
exits the pelvis, it is referred to as the femoral artery.
The external iliac artery
While the external iliac artery gives rise to the main blood supply of the lower limb, its distal
part also gives two branches within the pelvic area:
\u25cf Deep circumflex iliac artery- branches from the lateral side of the external iliac
artery. It ascends superiorly within the transversalis fascia towards the anterior
superior iliac spine. Past the iliac crest, it anastomoses with the superior branch of
the lateral circumflex femoral artery. Then, it travels along the interior aspect of the
iliac crest, perforates the transversus abdominis muscle, and runs between it and
between the internal abdominal oblique muscles. There, it gives a branch that
anastomoses with the lumbar arteries and the inferior epigastric artery.
o Supplies:
Transversus abdominis muscle
Internal abdominal oblique muscles
Iliac fossa<\/p>\n\n\n\n
\u25cf Inferior epigastric artery- originates in the medial aspect of the distal part of the
external iliac artery. It travels superiorly and medially, on the posterior surface of the
rectus abdominis muscle, giving branches to anastomose with the posterior
intercostal arteries. At about the level of the umbilicus, it anastomoses with the
superior epigastric artery.
o Supplies:
The inferior part of the rectus abdominis muscle.
o Branches
\u25aa Cremasteric artery (in males)- enters the deep inguinal ring and runs
within the spermatic cord to supply its layers, as well as the scrotal
skin and the cremaster muscle.
In females, this artery is rudimental and becomes a part of the round
ligament of the uterus.
\u25aa Pubic branch of the inferior epigastric artery runs towards the
obturator foramen, where it anastomoses with the pubic branch of
the obturator artery.<\/p>\n\n\n\n
\u25aa Corona mortis- variant vascular anastomosis (may also branch directly
from the external iliac artery) found in about half of the individuals. It
is located posteriorly to the superior pubic ramus and anastomose
with the obturator artery, therefore forming a vascular connection
between the internal and the external iliac arteries.<\/p>\n\n\n\n
o Clinical note:
\u25aa The inferior epigastric artery and vein constitute the lateral border of
the Hesselbach\u2019s triangle, through which the direct inguinal hernia
may protrude.
\u25aa The presence of Corona mortis anastomosis may also be important in
pelvic trauma or in pelvic surgery. Damage to such a connection may
lead to a massive hemorrhage that might be hard to control, and
therefore the name – \u201cthe crown of death\u201d.<\/p>\n\n\n\n
\u25cf Clinical note:
Many endovascular procedures that target the aorta (aortic aneurysm repair) utilizes
the femoral artery as an entry channel, and the external iliac artery as well (found
proximally). Therefore, narrowing of the external iliac artery for any reason may
implicate such procedures.
Venous drainage
The great majority of the pelvic veins run together with the arteries and are named
accordingly.
The intrapelvic venous plexus- the venous drainage system of the pelvis. Includes:
o Visceral tributaries- drains mainly visceral organs. include:<\/p>\n\n\n\n
\u25cf Vesical venous plexus- surrounding the urinary bladder and
drained by the vesicular veins into the internal iliac vein.
\u25cf Prostatic venous plexus- surrounding the prostate and drain
deep structures of the penis as well. it communicates with the
vesical venous plexus (both plexuses are sometimes referred
to as the vesicoprostatic or pudendal venous plexus). It is
drained into the internal iliac vein.
\u25cf Uterine venous plexus- surrounding the uterine body and
drained by the uterine veins, that extend laterally in the broad
ligament, into the internal iliac vein.
It anastomoses with the vaginal and ovarian plexuses as well.<\/p>\n\n\n\n
\u25cf Rectal venous plexus- surrounding the rectum and drained
through 3 different veins:
\u00b7 Superior rectal vein- drains into the inferior mesenteric
vein (into the portal circulation).
\u00b7 Middle rectal vein- drains into the internal iliac vein (caval
circulation).
\u00b7 Inferior rectal vein- drains into the internal pudendal vein
and then into the internal iliac vein (caval circulation).
\u25cf Perineal veins- drain the perineum and the external genitalia.
Empty into the internal pudendal vein and further into the
internal iliac vein.<\/p>\n\n\n\n
o Parietal tributaries- drains mainly musculoskeletal structures. Include:
\u25cf Superior gluteal vein- drain into the internal iliac vein.
\u25cf Inferior gluteal vein- drain into the internal iliac vein.
\u25cf Obturator vein- drain into the internal iliac vein.
\u25cf Lateral sacral vein- drain into the internal iliac vein. It also
collects blood from the regional intervertebral venous
plexuses.<\/p>\n\n\n\n
Although most of the veins follow the course of their corresponding artery, there are some
exceptions:
\u00b7 Iliolumbar vein- drain directly into the common iliac vein (unlike the iliolumbar artery
which is a branch of the posterior division of the internal iliac artery).
\u00b7 Median sacral vein- drain into the left common iliac vein (unlike the median sacral
artery that branches out of the posterior aspect of the abdominal aorta).
\u00b7 Gonadal veins- the left gonadal vein drains into the left renal vein, while the right
gonadal vein drains directly into the inferior vena cava (unlike the gonadal arteries that
branch both straight from the abdominal aorta).<\/p>\n\n\n\n
References<\/p>\n\n\n\n