The abdominal aorta descends through the abdomen and divides into the common iliac arteries. It gives off several branches that supply the abdominal organs and walls. The inferior vena cava returns blood from the lower body to the heart. It forms from the common iliac veins and pierces the diaphragm to drain into the right atrium. Injuries to the aorta and inferior vena cava can be life-threatening due to bleeding.

1. ABDOMINAL AORTA AND
INFERIOR VENA CAVA
By: Dr. Mujahid Khan

2. Location
 Aorta enters the abdomen through the
aortic opening of the diaphragm
 The opening lies in front of twelfth thoracic
vertebra
 It descends behind the peritoneum on the
anterior surface of the bodies of the
lumbar vertebrae

4. Location
 On its right side lies the inferior vena cava,
the cisterna chyli and beginning of the
azygos vein
 On the left side lies the left sympathetic
trunk
 It divides into two common iliac arteries at
the level of fourth lumbar vertebra

6. Branches
 Three anterior visceral branches: celiac
artery, superior and inferior mesenteric
arteries
 Three lateral visceral branches: suprarenal
artery, renal artery, testicular or ovarian
artery

8. Branches
 Five lateral abdominal wall branches: the
inferior phrenic artery and four lumbar
arteries
 Three terminal branches: two common
iliac and the median sacral artery

9. Common Iliac Arteries
 Right and left common iliac arteries are the
terminal branches of the aorta
 They arise at the level of fourth lumbar vertebra
 Runs downward and laterally along the medial
border of the psoas muscle
 Each artery divides into external and internal
iliac arteries in front of the sacroiliac joint

11. External Iliac Artery
 It runs along the medial border of psoas,
following the pelvic brim
 It gives off the inferior epigastric and deep
circumflex iliac branches
 The artery enters the thigh by passing
under the inguinal ligament to become the
femoral artery

12. Inferior Epigastric Artery
 The inferior epigastric artery arises just
above the inguinal ligament
 Passes upward and medially along the
medial margin of the deep inguinal ring
 Enters the rectus sheath behind the rectus
abdominis muscle

13. Deep Circumflex Iliac Artery
 Arises close to the inferior epigastric artery
 Ascends laterally to the anterior superior
iliac spine and the iliac crest
 Supplies the muscles of the anterior
abdominal wall

14. Internal Iliac Artery
 It passes down into the pelvis in front of
the sacroiliac joint

15. Aortic Aneurisms
 Localized or diffuse dilatations of the
abdominal part of the aorta usually occur
below the origin of the renal arteries
 Most result from atherosclerosis which
causes weakening of the arterial wall
 Occur most commonly in elderly men

16. Aortic Aneurisms
 Large aneurysms should be surgically
excised and replaced with a prosthetic
graft
 The bifurcation of the abdominal aorta
where the lumen suddenly narrows may
be a lodging site for an embolus from the
heart
 Severe ischemia of the lower limbs results

17. Obliteration of Abdominal Aorta and
Iliac Arteries
 Gradual occlusion of the bifurcation of the
abdominal aorta produced by atherosclerosis
causes pain in the legs on walking
 Impotence may occur due to lack of blood in
internal iliac arteries
 Surgical treatment by thromboendarterectomy or
a bypass graft should be considered

18. Inferior Vena Cava
 It conveys most of the blood from the body
below the diaphragm to the right atrium of the
heart
 It is formed by the union of common iliac veins
behind the right common iliac artery at the level
of fifth lumbar vertebra
 It ascends on the right side of the aorta
 Pierces the central tendon of the diaphragm at
the level of the eighth thoracic vertebra

20. Inferior Vena Cava
 It drains into the right atrium of the heart
 Right sympathetic trunk lies behind its
right margin
 Right ureter lies close to its right border
 The entrance into the lesser sac separates
the inferior vena cava from the portal vein

21. Tributaries
 Two anterior visceral tributaries: the hepatic
veins
 Three lateral visceral tributaries: the right
suprarenal vein, renal veins, right testicular or
ovarian vein
 Lateral abdominal wall tributaries: inferior
phrenic vein and four lumbar veins
 Three veins of origin: two common iliac veins
and the median sacral vein

23. Trauma to IVC
 Injuries to inferior vena cava are
commonly lethal
 The anatomical inaccessibility of the
vessel behind the liver, duodenum and
mesentery of the small intestine and the
blocking presence of the right costal
margin make a surgical approach difficult

24. Trauma to IVC
 The thin wall of the vena cava makes it
prone to extensive tears
 Due to the multiple anastomoses of the
tributaries of IVC, it is impossible in an
emergency to ligate the vessel
 Most patients have venous congestion of
the lower limbs

25. Compression of IVC
 It is commonly compressed by the
enlarged uterus during the later stages of
pregnancy
 This produces edema of the ankles and
feet and temporary varicose veins
 Malignant retroperitoneal tumors can
cause severe compression and eventual
blockage of IVC

26. Compression of IVC
 This results in the dilatation of the
extensive anastomoses of the tributaries
 This alternative pathway for the blood to
return to the right atrium is referred to as
the caval-caval shunt