Anatomy of the vessels of the posterior abdominal wall

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Introduction0:00–0:29

The major vessels of the abdomen, including the abdominal aorta and the inferior vena cava, course along the posterior abdominal wall.
Branches and tributaries of these vessels help supply and drain the posterior abdominal wall, and the abdominal viscera.
Important lymphatic vessels that help with drainage of the lower body are also found in this area. Let’s start off with the abdominal aorta, which gives rise to most of the arteries supplying the posterior abdominal wall.

Abdominal aorta0:29–0:57

It transitions from the thoracic aorta to the abdominal aorta starting at the aortic hiatus, located within the diaphragm, at the level of the T12 vertebra.
Then, it descends anterior to the vertebral bodies and ends at the level of the L4 vertebra. From superior to inferior, the abdominal aorta has a number of structures associated with it anteriorly.

Anatomical relations0:57–1:43

These include the celiac plexus and ganglia, the body of the pancreas, the splenic vein, the left renal vein, the horizontal part of the duodenum and the coils of the small intestine.
Structures to the right of the abdominal aorta include the inferior vena cava, azygos vein, cisterna chyli, and the thoracic duct.
Posteriorly, the left lumbar veins pass behind the aorta to reach the inferior vena cava. Now, let’s talk about the various branches that arise from the abdominal aorta.

Branches of the abdominal aorta1:43–4:19

These can be organized in three categories based on the “vascular plane” or direction in which the arteries branch from the abdominal aorta: first, there are paired visceral branches, that travel in the lateral plane; second, there are paired parietal branches, which travel in the posterolateral plane; and third, there are the unpaired visceral branches in the anterior midline plane.
The paired visceral branches include the middle suprarenal arteries, the renal arteries and the gonadal arteries which supply the suprarenal glands, kidneys, and the testicles in males and the ovaries in females respectively.
Next up are the paired parietal branches, which include: the inferior phrenic arteries and the lumbar arteries which supply the inferior surface of the diaphragm and posterior abdominal wall.
The subcostal arteries are paired parietal branches of the thoracic aorta, but they emerge below the diaphragm to supply the posterior abdominal wall.
Finally, the unpaired visceral branches include the celiac trunk, the superior mesenteric artery and the inferior mesenteric artery which supply the foregut, midgut and hindgut structures respectively.
The abdominal aorta terminates at the level of the L4 vertebra, where it bifurcates into the right and left common iliac arteries.
The two arteries diverge and run inferolaterally following the medial border of the psoas muscles to the pelvic brim. At this point, each common iliac artery divides into an external iliac artery and internal iliac artery.
The external iliac arteries follow the iliopsoas muscle. Before leaving the abdomen, the external iliac arteries give rise to the inferior epigastric arteries and deep circumflex iliac arteries, which supply the anterolateral abdominal wall.
The internal iliac artery passes medially over the pelvic brim and descends into the pelvic cavity to supply various structures of the pelvis.
Time for a quick quiz! Let’s see if you can remember the unpaired, and paired visceral branches of the abdominal aorta.

Quiz4:19–4:32

Inferior vena cava4:32–5:22

Great! Let’s talk about the venous drainage of the posterior abdominal wall, which are mainly tributaries of the inferior vena cava.
The inferior vena cava begins anterior to the L5 vertebra through the union of the common iliac veins just right of the median plane, inferior to the aortic bifurcation and posterior to the proximal part of the right common iliac artery.
The inferior vena cava then travels superiorly on the right side of the bodies of the L3 through L5 vertebrae and just to the right of the abdominal aorta.
Finally, the inferior vena cava leaves the abdomen by passing through the caval opening in the diaphragm at the level of the T8 vertebra.
The tributaries of the inferior vena cava correspond to the paired visceral and parietal branches of the abdominal aorta.

Tributaries of the inferior vena cava5:22–6:38

The veins that correspond to the unpaired visceral branches are tributaries of the hepatic portal vein, which send blood from the abdominal viscera to the liver first, for metabolic processing and detoxification.
Then this blood leaves the liver through the hepatic veins, which then drain into the inferior vena cava.Now, the veins that correspond to the paired visceral branches of the aorta include the right suprarenal vein, the right renal vein and left renal vein and the right gonadal vein.
Remember that the left suprarenal vein and gonadal vein drain directly to the left renal vein, and then to the inferior vena cava, while the right suprarenal vein, the right renal vein and the right gonadal vein all drain directly to the inferior vena cava.

Quiz6:38–6:48

Finally, the tributaries of the inferior vena cava that correspond to the paired parietal branches of the aorta include the inferior phrenic veins, and the 3rd and 4th lumbar veins and the common iliac veins.

Lymphatic drainage6:48–9:18

Let’s take a quick break and see if you can remember the level at which the inferior vena cava begins! Finally, let’s discuss the lymphatics of the posterior abdominal wall, which lie along the aorta, the inferior vena cava and the iliac vessels.
The common iliac lymph nodes receive lymph from the external and internal iliac lymph nodes. Then lymph from the common iliac lymph nodes passes to the right and left lumbar lymph nodes which lie on both sides of the inferior vena cava and aorta.
The right and left lumbar lymph nodes, which can also be classified as caval or aortic lymph nodes, receive lymph directly from the posterior abdominal wall, kidneys, ureters, testes or ovaries, uterus and uterine tubes.
The inferior mesenteric and common iliac lymph nodes, which drain the descending colon, pelvis and lower limbs, also send lymph to the right and left lumbar lymph nodes.
Lymph from the digestive tract, liver, spleen and pancreas pass along the celiac and superior and inferior mesenteric arteries to the pre-aortic lymph nodes, which are known more specifically as the celiac and superior and inferior mesenteric nodes.
The efferent lymphatic vessels from these lymph nodes give rise to lymphatic trunks, which eventually join to form the inferior end of the thoracic duct which is situated anterior to the bodies of the L1 and L2 vertebrae, specifically between the right crus of the diaphragm and the aorta.
Sometimes where the thoracic duct begins at the point of convergence between the main lymphatic trunks can look like a thin walled dilated sac called the cisterna chyli, which varies in size and shape.
All the lymphatic drainage from the lower half of the body converges in the abdomen to this inferior portion of the thoracic duct.

Quiz9:18–9:29

The thoracic duct then travels superiorly through the aortic hiatus in the diaphragm, and into the posterior mediastinum, where it collects more lymph from the left upper quadrant of the body.

Review9:29–12:17

Finally, the thoracic duct ends by entering the venous system at the junction of the left subclavian and internal jugular veins.
Okay, let’s see if you can remember the lymph node groups that lie within the posterior abdominal wall. All right, as a quick recap...
the abdominal aorta begins at the aortic hiatus, at the level of the T12 vertebra and ends at the level of L4 vertebra, bifurcating into the left and right common iliac arteries.
The paired visceral branches of the abdominal aorta are: the middle suprarenal arteries, the renal arteries and the gonadal arteries.
The paired parietal branches of the abdominal aorta are: the inferior phrenic arteries and the lumbar arteries. The unpaired visceral branches of the abdominal aorta are the celiac trunk, the superior mesenteric artery and the inferior mesenteric artery.
The tributaries of the inferior vena cava correspond to the paired visceral and parietal branches of the abdominal aorta.
The left suprarenal vein and gonadal vein drain directly to the left renal vein, and then to the inferior vena cava. The veins corresponding to the unpaired visceral arteries are tributaries of the hepatic portal vein.
Lymphatic vessels and lymph nodes in the abdomen lie along the aorta, the inferior vena cava and iliac vessels. Lymph from the common iliac lymph nodes passes to the right and left lumbar lymph nodes.
Lymph from the digestive tract, liver, spleen and pancreas drains into the pre-aortic lymph nodes, known specifically as the celiac, and the superior and inferior mesenteric nodes.
Lymphatic trunks from all of the nodes in the abdomen converge to form the beginning of the thoracic duct which sometimes look like a dilated sac called the