The spleen is a fist-sized organ that plays a significant role in maintaining the body’s health. It is a major component of the immune system and works tirelessly to manage the blood circulating throughout the body. Understanding its functions requires first pinpointing its location within the abdominal cavity.
Anatomical Placement of the Spleen
The spleen is located in the Left Upper Quadrant (LUQ) of the abdomen. This quadrant houses the stomach, a section of the liver, and the left kidney, with the spleen tucked away behind the stomach. For precise anatomical reference, the spleen resides in the left hypochondriac region.
Its placement is highly protected, situated beneath the lower rib cage, specifically under the ninth, tenth, and eleventh ribs on the left side. Because of this bony covering, the spleen is not palpable during a routine physical examination in a healthy adult. The organ rests near the fundus of the stomach, the left kidney, and the tail of the pancreas.
Essential Roles of the Spleen
The spleen performs a dual function, acting as both a blood filter and a central hub for immune activity. Its internal structure contains two main types of tissue: the red pulp and the white pulp.
The red pulp is responsible for blood maintenance, filtering the blood to remove old, damaged, or misshapen red blood cells. Macrophages break down these worn-out cells and recycle useful components like iron. The spleen also stores a reserve of blood, including up to a third of the body’s platelets, which can be released in cases of blood loss.
The white pulp is dedicated to immune defense, functioning as a large lymph node within the circulatory system. It houses and develops lymphocytes, the white blood cells responsible for producing antibodies and fighting infections. By trapping bloodborne microorganisms and antigens, the spleen mounts an immune response against harmful bacteria and viruses.
Why Spleen Location is Clinically Important
The spleen’s location under the ribs makes it susceptible to injury from blunt force trauma. A strong blow to the lower left rib cage, such as during an accident or contact sport, can fracture the ribs, potentially puncturing the spleen. A rupture is a medical emergency because of the risk of severe internal bleeding, making the spleen one of the most frequently injured abdominal organs.
The anatomical position also explains the symptoms associated with an enlarged spleen, known as splenomegaly. When the spleen swells due to infection or disease, it expands downward and forward from its LUQ position. This enlargement can cause pain or a feeling of fullness in the upper left side of the abdomen.