A_Anatomy

L4 bifurcates into the common iliacs.

Common Iliacs are about 4cm long in adults and more than a centimetre in diameter. The arteries run inferolaterally, along the medial border of the psoas muscles to their bifurcation at the pelvic brim, in front of the sacroiliac joints. This corresponds to the L5-S1 level.

The azygos vein is a vein running up the right side of the thoracic vertebral column. It can also provide an alternate path for blood to the right atrium by allowing the blood to flow between the venae cavae when one vena cava is blocked.

2: Gallblader fossa (history of cholecystectomy).
4: Portal vein.
5: Pancreatic tail.
6: Inferior vena cava.
7: Celiac artery.
8: Hepatic artery.
9: Descending aorta.
12, Spleen.
13, Right diaphragmatic crus.
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This axial CT at the T-12 level shows an enlarged lymph node in the porta hepatis. The porta is adjacent to the T-12 level so you can see the Celiac axis takeoff from the aorta.

The azygos vein is a vein running up the right side of the thoracic vertebral column. It can also provide an alternate path for blood to the right atrium by allowing the blood to flow between the venae cavae when one vena cava is blocked.

The so-called “aortopulmonary window” is a small space between the aortic arch and the pulmonary artery that contains the ligamentum arteriosum, the recurrent laryngeal nerve, lymph nodes, and fatty tissue. The space is also bounded anteriorly by the ascending aorta, posteriorly by the descending aorta, medially by the left main bronchus, and laterally by mediastinal pleura. The aortopulmonary window is commonly a location for lymphadenopathies and less commonly a location for neurogenic tumors or aneurysms. Left phrenic nv also courses through.

hepatic portal vein (entering)
hepatic artery proper (entering)
common hepatic duct (leaving)
The hepatic duct lies in front and to the right, the hepatic artery to the left, and the portal vein behind and between the duct and artery.It also transmits nerves and lymphatics.

Small bowel has plicae circularis and large bowel has haustra

Mediastinum borders
Superior: thoracic inlet
Inferior: diaphragm
Anterior: sternum
Posterior: vertebral column
Lateral: parietal pleural

PancreasL1-L2;
celiac axis and porta hepatis  T12;
SMA  L1 (just above the renal vessels)