Although the size of any organ can vary from person to person, the size of a normal spleen is approximately 11 centimeters in craniocaudal length, or along the long axis. It also weighs around 150 grams.
The spleen rests in the upper left portion of the abdomen, sitting under the rib cage and toward the back. It is part of the lymph system and helps defend the body against infection.
The spleen can increase in size while functioning normally, and an enlarged spleen does not necessarily indicate a problem. However, the enlargement could be caused by infection, cirrhosis, lymphatic problems or other serious conditions.