The spleen is located on the left side of the abdomen near the stomach. It plays an essential role in the body's defenses, storage of platelets, and is where much of the destruction of aging red blood cells takes place. It is a fragile organ that can break in cases of strong abdominal trauma, which will cause severe pain and shock. The spleen may also be increased in volume in certain disorders: this is called splenomegaly. It can also be painful in this case, or in other cases such as infections like mononucleosis, tumors, and diseases of the spleen or liver. The spleen may be examined by an ultrasound or CT scan.