Hey everyone! This is Nicole from Kenhub, and in this tutorial, we will be looking at the arteries of the abdomen and the pelvis. So before we begin talking about the arteries of the abdominal aorta, we're just going to start this tutorial by looking at the largest artery of the body – the aorta. And of course, the aorta arises directly from the heart after which it can be divided into three parts – the ascending aorta, the aortic arch and the descending aorta which is comprised of a thoracic part called the thoracic aorta located within the thoracic cavity and an abdominal part called the abdominal aorta located within the abdominal cavity. And the thoracic aorta runs posterior to the heart and is not entirely visible in this image.
And so of course this tutorial is about the arteries of the abdomen so in this slide we're going to have a bit of a chat about the abdominal aorta, and in this image, you can see the abdominal aorta highlighted in green emerging from the diaphragm. And the abdominal aorta is actually a distal continuation of the thoracic aorta which is above the diaphragm in this image and therefore not visible but nevertheless these two parts – the abdominal aorta and the thoracic aorta – make up the descending aorta. So as we just mentioned, the abdominal aorta begins after passing through the diaphragm and descends into the abdominal cavity until it reaches the level of the fourth lumbar vertebra L4. And as you can see once it's there it bifurcates into the right and left common iliac artery. And we'll have a chat about the common iliac arteries and their branches towards the end of this tutorial but first let's review the branches of the abdominal aorta which altogether are responsible for supplying the abdominal viscera and the musculature.
So in this lovely image, we can see the inferior aspect of the diaphragm and if we were lying at the model's feet and looking up at him or her towards the head, we would see this view. And of course our right is on the left here and our left is on the right. And we're looking at this view because we want to see the abdominal aorta in green as it emerges from the aortic hiatus of the diaphragm. We also want to see this view as it also shows us the abdominal aorta's first branches, so the left and right inferior phrenic arteries.
And so as you can see in the image, the left and right inferior phrenic arteries supply the inferior aspect of the diaphragm. They also give rise to the left and right superior suprarenal arteries that supply the superior aspects of the suprarenal gland also known as the adrenal gland which I'm pointing out with my arrows.
And in this image, we're looking at an anterior or ventral view of the abdominal cavity with the liver and gallbladder pulled back so that we can see the abdominal aorta below. And in both the main image and the breakout, we can see the celiac trunk which is the second branch arising from the abdominal aorta. And the celiac trunk is an unpaired visceral artery arising at the level of the twelfth thoracic vertebra T12 from the anterior aspect of the abdominal aorta. And as we can see in the breakout, it has a short trunk that passes under the median arcuate ligament of the diaphragm – so this ligament just here – and as you can see from all the organs it supplies, the celiac artery is a major visceral artery of the abdomen and it gives rise to three branches – the left gastric artery, the common hepatic artery, and the splenic artery.
The first of these arteries – the left gastric artery – is the most superior and smallest of the three branches of the celiac trunk and it descends into the left gastropancreatic fold to supply the lesser curvature of the stomach and we can see it in the image arising superiorly from the celiac trunk to supply the lesser curvature.
The second branch of the celiac trunk – the common hepatic artery – courses laterally to the right and superiorly to the porta hepatis or the transverse fissure of the liver. And the common hepatic artery supplies the liver, duodenum, pancreas and the lesser curvature of the stomach via its branches – the proper hepatic artery, the gastroduodenal artery and the right gastric artery. And in this image, you can see the right gastric artery anastomosing with the left gastric artery in the lesser curvature of the stomach which in this image we can't see as it's obstructed by the liver.
The third branch of the celiac trunk is the splenic artery and as its name describes, it directly supplies the spleen. Indirectly, it also supplies the fundus of the stomach and the greater curvature of the stomach by its branches – the short gastric arteries shown in red and the left gastroepiploic artery respectively.
And moving on from our celiac trunk, we have the next branch of the abdominal aorta – the middle suprarenal arteries. And the middle suprarenal arteries shown in green are paired arteries that arise from both sides of the abdominal aorta lateral to the celiac trunk. And the middle suprarenal arteries supply the anteromedial aspect of the adrenal glands which we can see in this image. And note that the superior suprarenal artery is a branch of the inferior phrenic artery.
And moving down again, we have the superior mesenteric artery, and the superior mesenteric artery is an unpaired visceral artery arising from the anterior aspect of abdominal aorta about 1 centimeter inferior to the celiac trunk and it's the second of only three unpaired visceral branches arising from the anterior abdominal aorta the first being the celiac trunk and the third we'll talk about a little bit later. And as we can see in this image, the superior mesenteric artery descends inferiorly passing posterior to the pancreas and the splenic vein and anterior to the left renal vein and the duodenum before it finally enters the mesentery and the mesocolon.
And the superior mesenteric artery supplies the pancreas which is not visible in this image as well as the intestines starting from the distal duodenum through to the mid-colon or the transverse colon. And this is achieved through several branches – the inferior pancreaticoduodenal artery which supplies the head of the pancreas and distal duodenum, the intestinal arteries supplying the jejunum and the ileum, the ileocolic artery which supplies the cecum, the right colic artery which supplies the ascending colon, and the middle colic artery only visible by its root here which supplies the proximal two-thirds of the transverse colon. And note that the superior mesenteric vein will be positioned to the right of the superior mesenteric artery and also note that near the ileum, the superior mesenteric artery anastomoses with the ileal branch of the ileocolic artery.
And after the superior mesenteric artery, we have the renal arteries. And the renal arteries are also paired arteries arising from the abdominal aorta lateral to the root of the superior mesenteric artery at approximately the level of the first and second lumbar vertebrae L1 and L2. And of course, the renal arteries supply the kidneys. And as you can see in this image, it's important to remember that due to the position of the inferior vena cava to the right of the abdominal aorta, the right renal artery is longer than the left renal artery.
The right renal artery indicated by the green arrow passes posterior to the inferior vena cava and the right renal vein entering the right kidney at the hilum. The left renal artery in green also courses posterior to the left renal vein and enters the left kidney at the hilum of the kidney. And before entering the kidneys, the renal arteries divide into anterior and posterior branches which enter at the hilum along with the renal vein and the ureter. And the renal arteries also give rise to some smaller branches – the inferior suprarenal artery which supply the lower part of the adrenal gland, the ureteric arteries which supply the ureters, and the capsular arteries which supply the renal capsule surrounding the kidney.
And the next braches that come off the abdominal aorta are the lumbar arteries which are highlighted in green in this image. And the lumbar arteries arise from the posterior aspect of the abdominal aorta. There are usually four pairs of lumbar arteries which course laterally and posteriorly over the bodies of the lumbar vertebrae, and the lumbar arteries pass laterally between the transverse processes of the adjacent lumbar vertebrae to the abdominal wall. And they also provide segmental branches that supply the spinal cord.
The gonadal arteries – the next arteries to come off the abdominal aorta – are paired arteries with both sides arising from the anterolateral aspect of the abdominal aorta below the origin of the renal arteries and at a level of approximately between the second and third lumbar vertebrae L2 and L3. And in this image, we can see the left gonadal artery highlighted in green, the right artery being the structure in red. And note that when we talk about the gonadal artery, we're referring to either the male gonadal artery which is the testicular artery or the female gonadal artery which is the ovarian artery.
So let's just have a look at the male gonadal artery for the time being – the testicular artery. And after the testicular artery arises from the abdominal aorta, it crosses over the ureter of its respective side and descends along the psoas major muscle before entering the deep inguinal ring. And in this image, we can see the testicular artery passing through the inguinal canal along with the other structures of the spermatic cord to supply the spermatic cord and the testes. And the testicular artery also gives off ureteric and epididymal branches.
The ovarian artery on the other hand follows a slightly different course due to the more superior location of the ovaries in comparison to the testes. So after the ovarian artery arises from the abdominal aorta, it descends on the psoas major muscle along with the ovarian vein crossing the ureter of its respective side and then passes into the pelvis anterior to the iliac vessels. The ovarian artery then travels medially through the suspensory ligament towards the uterus where it anastomosis with the uterine artery which is not visible in this image. And the ovarian artery supplies the ovaries, the fallopian tubes and the uterus.
So, earlier in the tutorial, we talked about there being three unpaired visceral arteries coming off the anterior abdominal aorta and if we remember the first one was the celiac trunk followed by the superior mesenteric artery and now we're coming to the third unpaired visceral artery – the inferior mesenteric artery. And the inferior mesenteric artery arises at approximately the level of the third lumbar vertebra L3 coursing inferiorly to the left to supply the abdominal hindgut. And the inferior mesenteric artery gives off the following branches – the left colic artery which supplies the distal transverse colon and the descending colon, the sigmoid arteries which supply the sigmoid colon, and the superior rectal artery which is the terminal branch of the inferior mesenteric artery and supplies the proximal rectum.
And moving on to the posterior aspect of the abdominal aorta, we find the median sacral arteries. And the median sacral arteries are an unpaired branch arising immediately superior to the abdominal aortic bifurcation into the left and right common iliac arteries. So, if we remember, we have three unpaired branches along the anterior aspect of the abdominal aorta – the celiac trunk, the superior mesenteric artery and the inferior mesenteric artery – whereas on the posterior aspect, we just have the one. And the median sacral arteries descend along the midline anteriorly to supply the L4 and L5 vertebrae, the sacrum, and the coccyx until it terminates into the coccygeal gland. The medial sacral arteries also supply the small branches of the posterior surface of the rectum and, morphologically speaking, the median sacral arteries can be considered the continuation of the abdominal aorta.
So now that we've discussed all the anterior and posterior branches of the abdominal aorta, let's have a look at its bifurcation. And at the level of the fourth lumbar vertebra L4, we can see how the abdominal aorta bifurcates forming a left and right common iliac artery. And the common iliac arteries which are of course paired arteries are considered the terminal branches of the abdominal aorta running inferolaterally along the medial border of the psoas major muscle until they each bifurcate into the external iliac artery and the internal iliac artery. And they do this bifurcation anterior to the sacroiliac joint at the level between the L5 and S1 vertebrae. And the left and the right common iliac arteries as well as the paired branches they give off supply the pelvis and the lower limbs.
And of course let's breakdown our common iliac artery branches by first looking at the external iliac artery. And the external iliac arteries are of course paired arteries and are the larger of the two terminal branches of the common iliac arteries. And the external iliac arteries descend medially along the iliopsoas muscle to enter the thigh and upon entering the thigh, the external iliac arteries become the femoral arteries. And since the external iliac arteries primarily supply the lower limb, in this tutorial, we will just focus on the shorter of the two terminal branches of the common iliac artery – the internal iliac artery.
And of course the internal iliac arteries are paired arteries supplying the pelvic organs, the external genitalia, the gluteal region and the medial thigh. The internal iliac arteries bifurcate into anterior and posterior divisions which we're now going to take a deeper look at. And there are quite a few branches so it might be helpful for you to look at an atlas while we discuss the following.
The anterior division of the internal iliac arteries continues towards the ischial spine and the anterior division gives off eight branches – the superior vesical artery which supplies the upper part of the bladder, the ureter and in males the seminal vesicles and the ductus deferens; the inferior vesical artery which supplies the fundus of the bladder, the prostate and seminal vesicles in males and, in females, it is known as the vaginal artery which supplies the mucosa of the vagina, the bulb of the vestibule and the fundus of the bladder; the middle rectal artery which supplies the rectal muscles; the obturator artery which supplies the obturator externus muscle as well as the medial thigh; the uterine artery in females which supplies the vagina, the uterus, the fallopian tubes and the ovaries; the internal pudendal artery which supplies the external genital; and the inferior gluteal artery which supplies the gluteal region and the thigh.
The posterior division of the internal iliac arteries passes towards the greater sciatic foramen and gives off three branches – the iliolumbar artery which supplies the psoas major, the quadratus lumborum muscle and the iliacus muscle; the lateral sacral artery whose superior branch supplies the skin and muscles dorsal to the sacrum; and the superior gluteal artery which is the largest artery in the posterior trunk. And the superior gluteal artery supplies the piriformis muscle, the obturator internus muscle, the gluteus maximus muscle and the skin over the sacrum.
Now that you just completed this video tutorial, then it’s time for you to continue your learning experience by testing and also applying your knowledge. There are three ways you can do so here at Kenhub. The first one is by clicking on our “start training” button, the second one is by browsing through our related articles library, and the third one is by checking out our atlas.
Now, good luck everyone, and I will see you next time.