The Spleen

Key points

• • The spleen lies in the upper left abdomen under the ribs (roughly the ninth to eleventh), with its long axis along the tenth rib, and is normally not palpable.
• • It is covered by peritoneum and connected by the gastrosplenic and splenorenal ligaments, which carry its vessels.
• • Its blood comes from the splenic artery (a branch of the coeliac trunk) and drains by the splenic vein, which helps form the portal vein.
• • Inside, the red pulp filters the blood and removes old or damaged red cells, while the white pulp is lymphoid tissue that mounts immune responses.
• • A notch on its upper border is a useful sign that a mass in the left upper abdomen is an enlarged spleen rather than another organ.
• • Although protected by the ribs, it is easily torn in injury and can bleed heavily, and it may be removed after severe damage.