Most of the arteries that supply the posterior abdominal wall come from the abdominal aorta. The subcostal arteries separate from the thoracic part of the aorta and are distributed below the twelfth rib. The abdominal aorta is approximately 13 cm long. It begins at the diaphragm’s aortic hiatus at the level of the T12 vertebra and ends at the level of the L4 vertebra dividing into right and left. iliacau communis. The aortic bifurcation level is 2-3 cm inferior and to the left of the navel in level cristae iliacae . Aa. iliacae communes diverge and flow inferolateral, following the medial edge m. psoasa major to the pelvic hoop. Here is each And. iliaca communis shared in And. internal iliac and And. external iliac. A. iliaca interna enters the pelvis, an And. iliaca externa coming up m. iliopsoas. Before leaving the abdomen, from And. iliacae externae separates And. epigastric inferior and And. circumflexa ilium profunda which supply the anterolateral abdominal wall.
Abdominal aortic relations
From superior to inferior, important anterior relations of the abdominal aorta are with:
- celiac plexus and ganglion
- the body of the pancreas and the splenic vein
- left renal vein
- the horizontal part of the duodenum
- small bowel bandages.
The abdominal aorta descends anteriorly from the body of the T12-L4 vertebrae. The left lumbar veins pass posteriorly from the aorta to v. cavae inferior. On the right side, the aorta touches v. azygos, tank chyle, ductus thoracicus, right crus diaphragm, and right celiac ganglion. The aorta touches the left crus of the diaphragm and the left celiac ganglion on the left.
Aortic pulsation and aortic abdominal aneurysm
Because the aorta lies posterior to the pancreas and stomach, these organs’ tumors can transmit aortic pulsations that can be mistaken for an abdominal aortic aneurysm, a localized enlargement of the aorta. Deep palpation can detect an aneurysm, usually the result of congenital or acquired weakness of the arterial wall. The large aneurysm’ pulsations can be felt to the left of the midline; you can easily move the pulsating mass from one side to the other. Different imaging methods can confirm the diagnosis if in doubt.
Acute rupture of the abdominal aortic aneurysm is associated with severe pain in the abdomen or back. If not recognized, such an aneurysm has a mortality rate close to 90% due to large blood loss. Surgeons can repair an aneurysm by opening it, inserting a prosthesis, and suturing the aneurysmal aorta wall over the prosthesis to protect it. Many vascular problems today are treated with endovascular catheterization procedures.
When the anterior abdominal wall is relaxed, especially in children and lean adults, the inferior part of the abdominal aorta can be pressed against the body of the L4 vertebra by firm pressure on the anterior abdominal wall over the navel. You can apply this pressure to control bleeding in the pelvis or lower limbs.
Abdominal aortic branches
Branches of the descending (thoracic and abdominal) aorta can be described using the three planes in which they originate and flow, the ‘vascular planes’ and can be classified as visceral or parietal, and paired or odd. The paired parietal branches of the aorta supply blood to the diaphragm and the posterior abdominal wall.
For And. The sacral median, an odd parietal branch, can be said to occupy the fourth (posterior) plane because it starts from the posterior surface of the aorta, just before its bifurcation.
Superficial anatomy of the abdominal aorta
The abdominal aorta may be shown on the anterior abdominal wall by a band (approximately 2 cm wide) extending along the midline. Approximately 2.5 cm is superior from the transpyloric plane to the point slightly inferior and the navel’s left. This point depicts the site of aortic bifurcation into common iliac arteries. As the site of aortic bifurcation, it is also taken to the left of the center of the line joining the crista iliac’s highest points. This imaginary line helps examine obese people for whom the navel is not a reliable landmark.