The spleen is a parenchymal organ found in the upper left abdomen (left hypochondrium) in the supramesocolic portion (i.e., above the transverse colon) of the abdominal cavity, in the splenic bed, between the posterior body wall of the stomach. and the anterior aspect of the left kidney, just below the diaphragm. It is related to the stomach, the tail of the pancreas, the angle of the left colon, the kidney, and the left adrenal gland.
The spleen is held in the splenic bed by fibrous ligaments and positive abdominal pressure, but despite this it is a fairly mobile organ.
It receives its arterial blood supply via the splenic artery, while venous waste blood is discharged into the splenic vein, one of three vessels that join to form the portal vein (which runs to the liver).
The spleen is surrounded by a fibrous capsule from which some partitions originate that are taken into the organ for a few millimeters accompanied by arterial vessels that serve to feed the organ. The spleen parenchyma is divided into two parts, both histologically and functionally different: the red pulp and the white pulp.