Enlarged Spleen Overview
The spleen is an important organ in the immune system. It is a bean shaped structure, located in the left upper portion of the abdominal cavity, under the diaphragm, protected by the 9th through 11th ribs, in the mid-back. The spleen typically weighs 150 grams (5.3 oz) in a typical adult and spans about 11 cm (4.3 inches) vertically in its longest dimension.
The functions of the spleen normally include clearance of invading organisms in the blood (bacteria) from the circulation, production of antibodies for the immune system, and removal of abnormal blood cells.
The spleen can enlarge by performing its normal functions in response to another medical condition. Certain infections, diseases affecting blood cells, increased splenic blood flow, and diseases invading the spleen are some common reasons for the spleen to enlarge. Splenomegaly is not always abnormal, and spleen size may not necessarily say much about its function.
A normal-sized spleen cannot be palpated (felt) during the physical examination of the abdomen, except in slender people. Enlarged spleen (splenomegaly) may be easier to palpate during careful abdominal examination. A small percentage of the normal American population may have a palpable or enlarged spleen.
A spleen weighing up to 500 grams (1.1 pounds) or between 11 to 20 cm (4.3 to 8 inches) in its longest dimension is considered enlarged. Splenomegaly greater than 1000 gm (2 lb 3.3 oz) or longer than 20 cm (8 inches) is considered severe or massive.
Medically Reviewed by a Doctor on 2/19/2016
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