Abdominal Aorta and Inferior Vena Cava

Study Notes

Begins at T12 as the continuation of the descending thoracic aorta.
Terminates at L4 where it bifurcates into two common iliac arteries.
Single Branches:
- Coeliac Trunk originates at the upper border of L1.
- Superior Mesenteric Artery arises at the lower border of L1.
- Inferior Mesenteric Artery stems from L3.
- Median Sacral Artery arises at L4.
Paired Branches:
- Inferior Phrenic Arteries originate at the upper border of L1.
- Middle Suprarenal Arteries arise at the lower border of L1.
- Renal and Gonadal Arteries emerge at the level of L2.
- Common Iliac Arteries appear at L4.
- Upper four Lumbar Arteries correspond to each lumbar vertebrae.
Median Sacral is the only branch arising from the posterior aspect of the aorta.
The last lumbar artery is derived from the Median Sacral Artery.

Begins at L5 from the union of the two Common Iliac veins.
Terminates in the right atrium at the level of the 6th costal cartilage (T8).
Tributaries:
- Hepatic Veins enter at T8.
- Inferior Phrenic Veins join at L1.
- Right Suprarenal Vein drains into it at L1.
- Renal Veins are tributaries at L2.
- Right Gonadal Vein connects at L3.
- 3rd and 4th Lumbar Veins enter at L3 and L4, respectively.
- Common Iliac Veins merge at L5.
The 1st and 2nd Lumbar Veins form the Ascending Lumbar Vein.
The Median Sacral Vein drains into the left Common Iliac Vein.
The left Gonadal, left Suprarenal, and left Inferior Phrenic Veins drain into the left Renal Vein.

Originates as the terminal branch of the Common Iliac Artery at the sacroiliac joint.
Branches:
- Posterior Division: All branches are parietal.
  - Ilio-lumbar Artery supplies iliac and lumbar areas.
  - Lateral Sacral Artery serves the sacral canal contents.
  - Superior Gluteal Artery continues from the posterior division to supply the gluteal region.
- Anterior Division: Mainly visceral branches except for a few.
  - Obturator Artery supplies the thigh.
  - Umbilical Artery provides a superior vesical branch to the urinary bladder, with its distal portion obliterating to form the lateral umbilical ligament.

Begins at the T12 level as a continuation of the descending thoracic aorta.
Terminates at the L4 level, bifurcating into the two common iliac arteries.
Single branches:
- Celiac trunk: Arises at the upper border of L1.
- Superior mesenteric artery: Arises at the lower border of L1.
- Inferior mesenteric artery: Arises at L3.
- Median sacral artery: Arises at L4 (only branch from the back of the aorta).
Paired branches:
- Inferior phrenic arteries: Arise at the upper border of L1.
- Middle suprarenal arteries: Arise at the lower border of L1.
- Renal and gonadal arteries: Arise at L2.
- Common iliac arteries: Arise at L4.
- Upper four lumbar arteries: Arise opposite each lumbar vertebrae.
The last lumbar artery is a branch from the median sacral artery.

Begins at the L5 level from the union of the two common iliac veins.
Terminates by opening into the right atrium at the level of the 6th costal cartilage (T8).
Tributaries:
- Hepatic veins: Drain at T8.
- Inferior phrenic veins: Drain at L1.
- Right suprarenal vein: Drains at L1.
- Renal veins: Drain at L2.
- Right gonadal vein: Drains at L3.
- 3rd and 4th lumbar veins: Drain at L3 and L4.
- Common iliac veins: Drain at L5.
Ascending lumbar veins form from the 1st and 2nd lumbar veins.
The median sacral vein drains into the left common iliac vein.
The left gonadal, left suprarenal, and left inferior phrenic veins drain into the left renal vein.

Originates as the terminal branch of the common iliac artery at the sacroiliac joint.
Branches:
- Posterior division: All branches are parietal.
  - Ilio-lumbar artery: Provides iliac and lumbar branches.
  - Lateral sacral artery: Supplies content of the sacral canal.
  - Superior gluteal artery: Continuation of the posterior division supplying the gluteal region.
- Anterior division: Primarily visceral branches, except for branches 1, 6, and 7.
  - Obturator artery: Supplies the thigh.
  - Umbilical artery: Gives rise to the superior vesical artery for the urinary bladder; distal part forms the lateral umbilical ligament.