The spleen is an encapsulated organ located below the diaphragm in the left upper abdomen. It weighs about 150 g. The connective capsule contains some smooth muscle fibers penetrating into the parenchima. Trabeculae and reticular fibers form a supporting net for different cells of the white pulp and the red pulp,
The white pulp consists of periarterial lymphatic tissue and lymphatic noduli. Both structures make up 16-18% of the splenic tissue.
The red pulp consists of sinuses and cords; they comprise 76-79% of the splenic tissue.