Arteries and veins of the pelvis

Definitions & Key takeaways

There are a few different arteries and veins that serve and drain the pelvic region. The main artery is the iliac artery, which branches off into the internal iliac artery and the external iliac artery. The internal iliac artery supplies blood to the pelvic organs, while the external iliac artery supplies blood to the lower extremities.

The veins of the pelvis include the internal iliac veins, which unite with the external iliac veins to form two common iliac veins, one on the right, and the other one on the left. The two common iliac veins unite to form the inferior vena cava, which drains into the right atrium of the heart.

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Introduction0:00–0:31

The pelvis contains numerous structures, all supplied by the neurovascular structures of the pelvis, including nerves, arteries, veins, and lymph nodes.
These structures are found on the posterolateral walls of the pelvic cavity. Lymph nodes are usually clustered around the veins, and lymph vessels that come off these nodes ascend parallel to the veins.
Let's focus our attention on the arteries and veins of the pelvis. Now the arteries of the pelvis originate from the abdominal aorta, which is the continuation of the thoracic aorta below the aortic hiatus in the diaphragm.

Abdominal aorta0:31–1:05

The abdominal aorta gives branches to various organs in the abdomen, then divides at the level of the 4th lumbar vertebra into the right and left common iliac arteries.
Each artery runs inferilaterally and ends at the level of the intervertebral disc between L5 and S1 by dividing into the internal and external iliac arteries.
Let's talk about each of those branches. First are the external iliac arteries which descend on the medial border of a muscle called the psoas major.

External iliac arteries1:05–1:39

After running for a short distance, each external iliac artery gives two branches called the inferior epigastric and deep circumflex iliac arteries.
These branches supply the anterolateral aspect of the abdominal wall. Then each external iliac artery passes underneath the inguinal ligament to become the femoral artery, which is the main artery that supplies the lower limbs.
Next are the internal iliac arteries, which are the main arteries of the pelvis and also supply parts of the gluteal region, medial thigh, and perineum.

Internal iliac arteries1:39–2:27

The branching pattern of the internal iliac arteries is one of the most variable in the body. So in order to identify each branch, we must think about the structures they're nourishing.
Each internal iliac artery runs posterome medially to reach the upper border of the greater sciatic foramen. Then each internal iliac artery divides into anterior and posterior divisions or trunks.
These trunks give smaller branches that are either visceral or parietal. Visceral branches supply organs like the bladder and the rectum, and parietal branches supply muscles and skin that form the walls of the pelvic cavity.

Anterior division of the internal iliac artery2:27–3:40

Let's zoom in on the branches of the anterior division of the internal iliac artery. There are 9 branches coming off the anterior division of the internal iliac artery the umbilical, superior vesicle, inferior vesicle, operator, uterine, middle rectal, internal pudendal, and the inferior gluteal arteries.
And in biologically female individuals, there are also vaginal arteries. To make things a bit easier to remember, these branches are grouped into 3 categories, each with 3 branches.
The first group includes the branches that supply the urinary organs, which are the umbilical, superior vesicle, and inferior vesicle arteries.
The next group has 3 branches that supply the organs of the pelvis, which are the uterine, vaginal, and middle rectal arteries.
Finally, 3 branches supply the walls of the pelvis, and these are the operator, internal pudendal, and inferior gluteal arteries.
Remember that these branches also supply structures of the genitourinary tracts, so they'll have variations depending on whether you're born biologically male or female.

Umbilical arteries3:40–5:10

So let's start off with the umbilical arteries, which run anteroinferiorly along the lateral wall of the pelvis and ascend towards the umbilical ring.
Before birth, the umbilical arteries are the main continuation of the internal iliac arteries and pass through the umbilical ring and travel through the umbilical cord to deliver nutrient and oxygen poor blood from the fetus to the placenta.
Here, the blood becomes replenished with nutrients and oxygen and is sent back to the fetus by the umbilical vein. After birth, the umbilical cord is cut and the umbilical arteries obliterate distally.
The obliterated parts of the umbilical arteries persist as fibrous cords called the medial umbilical ligaments, and they're covered by folds of peritoneum called the medial umbilical folds.
In an adult, these folds are seen on the inside of the anterior abdominal wall, and they sit lateral to the median umbilical fold which contains the urachus, another fibrous remnant of an embryonic structure called the allantois.
Finally, lateral to the medial umbilical folds, there are the lateral umbilical folds, which is peritoneum covering the inferior epigastric artery and vein.
So to quickly summarize, remember the single median umbilical fold sits on the median line of the body. The paired medial umbilical folds are on either side of the median umbilical fold.
And finally, the lateral umbilical folds are most lateral. OK, now each umbilical artery gives multiple superior vesicle artery branches proximal to the medial umbilical folds in adults.

Superior vesical arteries5:10–5:35

The superior vesicle arteries supply the superior aspect of the urinary bladder. In males, the superior vesicle arteries may also give a branch to the ductus deferens or vas deferens, which facilitates the transport of sperm from the scrotum.

Inferior vesical arteries5:35–6:05

There's also an inferior vesicle artery that's only found in males, whereas in females, it's replaced by the vaginal artery which has inferior vesicle branches.
In males, the inferior vesicle arteries supply the inferior aspect of the urinary bladder, the prostate gland, seminal glands, and pelvic parts of the ureters.
Finally, the branch to the ductus deferens may arise from the inferior vesicle arteries instead of arising from the superior vesicle arteries.
Next are the operator arteries, which pass anteroinferiorly on the operator fascia that covers the operator foramen. Interestingly, in 20% of the population, an accessory or aberrant operator artery arises from the inferior epigastric artery.

Obturator arteries6:05–6:58

Before leaving the pelvis, each operator artery gives off multiple branches. First are muscular branches which supply the muscles of the pelvis.
Then it gives a nutrient artery that supplies part of the ileum. Finally, it gives a branch called the pubic branch which ascends on the internal surface of the pubis.
Each pubic branch anastomoses with the pubic branch of the opposite side. Finally, the operator artery passes through the operator canal to enter the lower limb and supply the medial compartment of the thigh.
Next are the uterine arteries, which are the female counterpart to the artery of ductus deferens in males. These arteries most often arise from the anterior division of the internal iliac artery, but may arise from the umbilical artery.

Uterine arteries6:58–8:03

Now the uterine arteries descend on the lateral walls of the pelvis, crossing superior to the ureters on each side, and then turn medially to reach the junction between the cervix and the vagina.
You can think about the uterine arteries as a bridge over a river, where the bridge is the uterine artery and the river is the urine passing through the ureters to the urinary bladder.
At the junction of the cervix and the vagina, each uterine artery divides into two branches, a small descending branch called the vaginal branch, which supplies parts of the vagina and the cervix, and a larger ascending branch, which runs superiorly along the lateral margins of the uterus supplying it.
Each ascending branch gives two branches the ovarian branch, which supplies the medial aspect of the ovaries, and the tubal branch, which supplies the medial end of the uterine or fallopian tube.
And now an important point. Besides the vaginal branch of the uterine artery, in females, there's also a vaginal artery per se.

Vaginal arteries8:03–8:37

The vaginal artery gives two branches, the vaginal branch, which gives multiple branches for the anterior and posterior aspects of the vagina, and the inferior vesicle branch, which nourishes the inferior aspect and the fundus of the urinary bladder.
The vaginal artery anastomoses with the vaginal branch of the uterine artery, and the inferior vesicle branches anastomos with the superior vesicle branches of the umbilical artery.

Middle rectal artery8:37–9:03

Next is the middle rectal artery, which can have a variable origin from the anterior division of the internal iliac artery and descends into the pelvis to supply the inferior parts of the rectum, the prostate, and seminal gland in males, as well as parts of the vagina in females.
The middle rectal artery anastomosis with the superior and inferior rectal arteries to supply the whole rectum. There's also the internal pudendal artery, which descends and runs anterior to the piriformis muscle and the sacral plexus.

Internal pudendal artery9:03–9:47

Then it leaves the pelvis by going through the greater sciatic foramen inferior to the piriformis muscles. Finally, the internal pudendal artery loops around the ischial spine along with the internal pudendal vein and the pudendal nerve to enter the ischioanal fossa via the pudendal canal.
Then it passes through the lesser sciatic foramen to supply structures in the perineum anteriorly and anterolaterally. The perineum is bounded by the symphysis pubis and the ischiopubic rami.
Posteriorly, the perineum is bounded by the lower part of the sacrum and the coccyx. Finally, there's the inferior gluteal artery, which is the largest terminal branch of the anterior division of the internal iliac artery.

Inferior gluteal artery9:47–10:39

However, it may also originate from the posterior division in some individuals. Remember when we said that there was a lot of variability in this area?
Well, we hate to say we told you so. The inferior gluteal artery passes posteriorly, usually between the 2nd and the 3rd sacral spinal nerves, S2 to S3.
Then it leaves the pelvis next to the internal pudendal artery, inferior to the piriformis muscle. The name of this artery gives a clue about the structures it supplies, namely the gluteus maximus, which is the largest muscle in the human body.
This artery also supplies muscles of the pelvic diaphragm, quadratus femoris, and piriformis muscles. Finally, it supplies the sciatic nerve, which is the largest nerve in the human body.
OK, so let's switch gears and talk about branches of the posterior division of the internal iliac artery. These branches can be remembered with the mnemonic pills G.

Posterior division of the internal iliac artery10:39–11:04

P means that this mnemonic is used to remember branches off the posterior division. IL is for the iolumbar artery.
L is for the lateral sacral artery, and SG is for the superior gluteal artery. Let's start with the iliolumbar artery.

Iliolumbar artery11:04–11:38

Its course is a bit different from other arteries, meaning it runs in the opposite direction of its origin. Instead of running inferiorly like the posterior division, it runs slaterally, reaching the iliac fossa.
In the fossa, the iolumbar artery gives two branches called the iliac and lumbar branches. The iliac branch supplies the ileum and the muscle covering the iliac fossa called the iliacu, while the lumbar branch supplies the psoas major and quadratus lumbarum muscles.
Next are the superior and inferior lateral sacral arteries which may arise independently from the posterior division or arise as a common trunk.

Lateral sacral arteries11:38–12:12

The lateral sacral arteries pass both medially and descend anterior to the ventral rami of sacral nerves. These arteries give off the sacral branches which pass through the anterior sacral foramina to supply the meninges surrounding the roots of sacral nerves.
Also, some branches of lateral sacral arteries pass through the posterior sacral foramina to supply a group of back muscles called the erector spine muscles.

Superior gluteal artery12:12–12:41

The last branch of the posterior division is the superior gluteal artery, which is the largest branch of the posterior division.
This artery exits the pelvis through the greater sciatic foramen directly above the piriformis muscle. Then it enters the gluteal region to supply the gluteus maximus, mediaus, and minimus.
So the gluteus maximus actually receives blood supply from both the inferior and superior gluteal arteries. OK, now let's take a deep breath and have a quick quiz.

Quiz12:41–13:34

This illustration shows branches of the anterior and posterior divisions of the internal iliac artery. So do you recognize this artery?
This is the iolumbar artery, which is a branch of the posterior division. Pro tip, the iolumbar artery is easy to find because it runs in the opposite direction of its origin.
OK, let's have another quick question. Can you name these arteries?
Yep, these are the superior vesicle arteries that arise from the anterior division. These are easy to find because they run to supply the superior surface of the urinary bladder.
Last question, can you name this artery? Aha, it's the umbilical artery, which has an obliterated distal part running up to the umbilicus.

Abdominal aorta branches13:34–13:49

Now we also need to mention that there are some arteries that arise directly from the abdominal aorta and make their way down to the pelvis.
These arteries are the gnatal arteries, median sacral artery, and superior rectal artery. The gonadal arteries supply the gonads, which are the testes in males and the ovaries in females.

Gonadal arteries13:49–14:59

The course of gonadal arteries is similar between males and females, but the names are different. In males, they're called the testicular arteries, and in females, they're called the ovarian arteries.
The gonatal arteries arise laterally from the abdominal aorta between the renal artery above and the inferior mesenteric arteries below.
The gonadal arteries then descend towards the pelvis where they travel behind the peritoneum and anterior to the ureters to which they also supply branches.
Our bridge over a river memory trick applies here as well. Then they enter the lesser pelvis and run medially to cross the origin of external iliac vessels.
Now the distal extension of the gnatal arteries differs between males and females. In males, the testicular artery runs through the inguinal canal and enters the scrotum to supply the testes and the epididymis.
In females, each ovarian artery gives two branches. These are the ovarian branch, which supplies the ovaries and the tubal branch, which supplies the fallopian tube.

Median sacral artery14:59–15:47

Next is the median sacral artery. This small single artery arises from the anterior or posterior surfaces of the abdominal aorta just above its bifurcation.
After originating, the median sacral artery runs inferiorly along the anterior surface of the lower two lumbar vertebrae, the sacrum, and the coccyx.
As it travels distally, the median sacral artery gives off parietal and visceral branches. The parietal branches are called lateral sacral branches, which run laterally to anastomos with the superior and inferior lateral sacral arteries.
Finally, the visceral branches run to the posterior surface of the rectum. There, these branches anastomose with the superior and middle rectal arteries and help provide minor blood supply to the rectum.

Superior rectal artery15:47–16:14

Finally, there's the superior rectal artery, which is the direct continuation of the inferior mesenteric artery, a branch of the abdominal aorta which supplies the large intestine.
Now the superior rectal artery descends inferiorly to cross the left common iliac vessels. Then it runs on the sigmoid colon to enter the lesser pelvis to supply each side of the rectum as far down as the internal anal sphincter.
Now that we have gone through all of the arteries of the pelvis, let's review these arteries by focusing on the blood supply of major pelvic organs, starting with the bladder.

Bladder vascular supply16:14–16:46

The bladder is supplied by the superior and inferior vesicle arteries. The superior vesicle artery arises from the umbilical artery and supplies the superior aspect of the bladder.
Next, the inferior bladder is supplied by the inferior vesicle artery in males and the inferior vesicle branches in females which originate from the vaginal artery.
Next is the blood supply of the female internal reproductive organs, which are the ovaries, fallopian tubes, uterus, and vagina.

Female internal reproductive organ vascular supply16:46–17:40

Now the ovaries are mainly supplied by the ovarian arteries which arise as direct branches from the abdominal aorta. The ovarian branches of the uterine artery also supply the medial aspect of the ovaries.
Next are the fallopian tubes. These tubes are supplied by tubal branches that arise from uterine and ovarian arteries.
Then comes the uterus, which is mainly supplied by the uterine artery, which arises as a direct branch from the anterior division of the internal iliac artery.
Finally, the vagina is mainly supplied by the vaginal artery, which typically arises as a branch from the uterine artery.
Additionally, small branches from the descending branch of the uterine artery provide blood to the vagina. Next is the blood supply of male reproductive organs which are the testes, the prostate, and the ductus deferens.

Male internal reproductive organ vascular supply17:40–18:17

Now the testes are supplied by the testicular artery which arises as a direct branch from the abdominal aorta. The prostate is supplied by branches from the middle rectal and inferior vesicle arteries which arise as direct branches from the anterior division of the internal iliac artery.
Finally, the ductus deferens is supplied by the artery to the ductus deferens, so no surprises there. This artery mainly arises from the superior vesicle artery and sometimes from the inferior vesicle artery.

Rectum and anal canal vascular supply18:17–19:18

Finally, let's look at the blood supply to the rectum and the anal canal which form the terminal parts of the gastrointestinal tract.
The rectum is supplied by 3 main arteries called the superior, middle, and inferior rectal arteries. The superior rectal artery is the continuation of the inferior mesenteric artery, a direct branch of the abdominal aorta.
The middle rectal artery arises from the anterior division of the internal iliac artery. Finally, the inferior rectal artery arises from the internal pudendal artery.
The three rectal arteries may all anastomose with each other. Next, there's the anal canal, which is divided into an upper 2/3 and a lower 1/3 by a line called the pectinate or dentate line.
The part of the anal canal that's above the dentate line is mainly supplied by the superior rectal artery, and the part below the dentate line is mainly supplied by the inferior rectal artery.
Also, branches from the middle rectal artery supplies both parts of the anal canal. Now let's switch gears and talk about the pelvic veins.

Major pelvic veins19:18–20:54

The major veins of the pelvis are the internal iliac veins. These veins form superior to the greater sciatic foramen and pass postero inferior to the internal iliac arteries.
Generally, the names of the venous tributaries that drain into the internal iliac veins are similar to the names of the branches that come off the internal iliac artery.
However, they are more variable. Additionally, these tributaries drain the same areas that the arteries supply.
Exceptions include the umbilical arteries, which don't have accompanying umbilical veins, as well as the iolumbar veins, which originate in the iliac fossa and drain into the common iliac veins instead of the internal iliac veins.
It's particularly important to understand the drainage of the testicular veins in males and ovarian veins in females. As the testicular and ovarian arteries are branches of the abdominal aorta, you would expect these veins to drain to its counterpart, the IVC.
However, the right and left gonadal veins drain into different vessels. The right gonadal vein drains directly into the inferior vena cava, just below the right renal vein.
On the other hand, the left gonadal vein drains into the left renal vein, which then drains into the inferior vena cava.
Finally, the internal iliac veins unite with the external iliac veins to form the common iliac veins. Then the right and left common iliac veins unite at the level of L4 or L5 to form the inferior vena cava, which runs upwards to drain into the right atrium of the heart.
In addition to the tributaries of the internal iliac vein, there are multiple pelvic veins which are organized into interjoining networks called pelvic venous plexuses.

Pelvic venous plexuses20:54–21:58

These plexuses are named according to the name of the organ they surround. For example, venous plexuses surrounding the rectum are called rectal venous plexuses.
Other venous plexuses include vesicle, prostatic, uterine, and vaginal venous plexuses. Now these venous plexuses mainly drain into the tributaries of the internal iliac veins.
However, some drain into the superior rectal vein, which goes on to drain into the inferior mesenteric vein and onto the hepatic portal system.
Now, because the superior rectal vein drains into the hepatic portal system, it creates what is called a portal caval anastomosis in the pelvis at its anastomosis point with the middle and inferior rectal veins, which both drain into the systemic venous system or caval system.
This is clinically relevant when there's increased pressure in the portal hepatic system, leading to congestion and varices at these anastomosis points.
Furthermore, some of the venous plexuses will drain into the lateral sacral veins, which drain into another plexus found in the spinal canal called the internal vertebral plexus.

Internal vertebral plexus21:58–22:26

This connection between the lateral sacral veins and the internal vertebral plexus allows potential metastasis of prostatic or ovarian cancers to vertebral or cranial sites.
Finally, a minority of the pelvic venous plexuses drain into the median sacral and ovarian veins. All right, as a quick recap, pelvic arteries supply oxygenated blood to the structures of the pelvis.

Review22:26–24:04

The main artery that supplies structures of the pelvis is called the internal iliac artery, which bifurcates into an anterior division and a posterior division.
Now, to make things a bit easier, branches off the anterior division are grouped into 3 categories. The first group has 3 branches that supply the urinary organs, which are the umbilical, superior vesicle, and inferior vesicle arteries.
The next group has 3 branches that supply organs of the pelvis, which are the uterine, vaginal, and middle rectal arteries.
Finally, 3 branches supply the walls of the pelvis, which are the operator, internal pudendal, and inferior gluteal arteries.
Next are branches off the posterior division, which can be remembered with the mnemonic pills G. P means that this mnemonic is used to remember the branches off the posterior division.
IL is for the iolumbar artery. L is for the lateral sacral artery, and SG is for the superior gluteal artery.
Finally, 3 branches come off the aorta and go down to supply structures in the pelvis. These are the gonadal arteries, median sacral artery, and superior rectal artery.
Finally, pelvic venous plexuses lie on the surfaces of pelvic organs. These plexuses intercommunicate with each other and with superior veins and form clinically important connections such as the porta caal anastomosis of the rectal veins and the open communications between the lateral sacral veins and internal vertebral plexus.