**3. Splenic Artery Aneurysms (SAAs)**

#### **3.1. General considerations**

An arterial aneurysm is one of the most common vascular disorders causing morbidity and mortality in humans. It occurs in most arteries of the body and is especially common in the elderly. They have a variable sizes, shapes, and locations.

An aneurysm is defined as a permanent localized dilatation of an artery having at least a 50% increase in diameter compared to the expected normal arterial diameter, so clinicians should know the normal arterial diameters throughout the body to decide the presence or absence of an aneurysm. [7]

Splenic artery aneurysms are a type of splanchnic arteries aneurysm, although the later are rare but clinically very important vascular conditions. These interesting lesions have been recognized since more than 200 years. [8, 9]

Splanchnic artery aneurysms represent intra-abdominal aneurysms that are not part of the aorto-iliac system and include aneurysms of the celiac, superior and inferior mesenteric arteries with their branches.

Of all intra-abdominal aneurysms, only approximately 5% affect the splanchnic arteries. (10) In general population, their prevalence has been estimated to be varying from 0.1% to 2 %. [11]

The frequency of the anatomic distribution of the splanchnic arteries aneurysms is estimated to be the following:

