What is the Spleen?

The Location, Function, and Common Problems of the Spleen

Illustration of spleen
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What is the spleen? The spleen is an abdominal organ that is part of the infection-fighting lymphatic system. It is located on the left side of the body next to the stomach and just under the rib cage. The spleen is a soft and spongy organ about as big as your fist.

Types of Spleen Tissue

The spleen is made up of two basic types of tissue, called pulp, each with different functions. The white pulp is part of the immune system.

It produces white blood cells called lymphocytes. The red pulp filters the blood, removing unwanted material such as bacteria.

Common Spleen Injuries and Health Concerns

A damaged spleen often releases blood into the abdomen. Tears in the spleen can be small ones that stop bleeding on their own or very large ones that can bleed uncontrollably, resulting in death. A hematoma of the spleen does not initially bleed into the abdomen but can rupture and bleed later, from days to months.

An injured or ruptured spleen can create a lot of pain in the left side of the abdomen just below the rib cage. Other times the pain is felt in the left shoulder. The abdominal muscles will sometimes contract and feel rigid. If enough blood leaks out, blood pressure will drop and you might feel light-headed, have blurred vision and confusion, and lose consciousness (faint).

About Spleen Surgery: Splenectomy

Sometimes the spleen must be removed surgically (called a splenectomy).

This often happens when the spleen in damaged by an injury. The spleen is the most commonly injured organ in the abdomen as a result of motor vehicle crashes, falls, athletic injuries, and beatings. Doctors usually do ultrasound or CT scan of the abdomen if they suspect an injury to the spleen.

A spleen is also sometimes removed if certain disorders including infections, anemias, and cancers cause the organ to become very large.

Enlargement of the spleen also makes the spleen more susceptible to injury. Symptoms of an enlarged spleen can include fullness or pain in the upper left abdomen or back. Usually doctors can feel an enlarged spleen, but often times x-rays will determine how large the spleen is. Treating the underlying disorder that is causing the spleen to enlarge usually takes care of the problem, but sometimes the spleen must be removed.

People can live without a spleen -- it is not critical to survival. But when the spleen is removed, the body is less able to produce protective antibodies and remove unwanted microorganisms, including certain types of bacteria, from the blood. The body is then less able to fight infections. People who do not have a spleen are at a higher risk of infection.


MedlinePlus [Internet]. Bethesda (MD): National Library of Medicine (US). Spleen diseases. Available from: https://www.nlm.nih.gov/medlineplus/spleendiseases.html

Merck Manual, Harry S. Jacob, M.D. Overview of the Spleen, 2015.

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