A plate from Gray's Anatomy with yellow lines depicting the most common infrarenal location of the<unk>  3D file showing an<unk><unk>  The most striking histopathological changes of the<unk> atic aorta are seen in the tunica media and intima layers. These changes include the accumulation of lipids in foam cells, extracellular free cholesterol crystals, calcifications, thrombosis, and ulcerations and ruptures of the layers. Adventitial inflammatory infiltrate is present. However, the degradation of the tunica media by means of a proteolytic process seems to be the basic pathophysiologic mechanism of<unk>  development. Some researchers report increased expression and activity of matrix metalloproteinases in individuals with<unk> . This leads to elimination of elastin from the media, rendering the<unk>  wall more susceptible to the influence of blood pressure. Other reports have suggested the serine protease granzyme B may contribute to<unk><unk>  rupture through the cleavage of decorin, leading to disrupted collagen organization and reduced tensile strength of the adventitia. There is also a reduced amount of vasa vasorum in the<unk>  aorta (compared to the thoracic aorta); consequently, the tunica media must rely mostly on diffusion for nutrition, which makes it more susceptible to damage. Hemodynamics affect the development of<unk> , which has a predilection for the infrarenal aorta. The histological structure and mechanical characteristics of the infrarenal aorta differ from those of the thoracic aorta. The diameter decreases from the root to the<unk>  bifurcation, and the wall of the infrarenal aorta also contains a lesser proportion of elastin. The mechanical tension in the<unk><unk>  wall is therefore higher than in the thoracic<unk>  wall. The elasticity and distensibility also decline with age, which can result in gradual dilatation of the segment. Higher intraluminal pressure in patients with arterial hypertension markedly contributes to the progression of the pathological process. Suitable hemodynamic conditions may be linked to specific intraluminal thrombus (ILT) patterns along the<unk>  lumen, which in turn may affect<unk> 's development.
Abdominal aortic aneurysm
Appendicitis
Superior mesenteric artery syndrome
Splenic infarction
Aortoenteric fistula
Postcholecystectomy syndrome
Renal vein thrombosis
Spontaneous bacterial peritonitis