The spleen (Latin: splen s. lien) is a secondary lymphoid organ and the lymphatic system’s largest organ. It has an essential role in the immune response and blood filtration. It is the organ where senescent and damaged red blood cells are degraded and recycled, but lymphocytes maturate and proliferate. If an antigen is in the organism, the spleen takes part in the immune response by creating plasma cells collaborating with three immune cells (B lymphocytes, T lymphocytes, and macrophages). Plasma cells then develop antibodies and provide humoral immunity. The spleen is responsible for cell-mediated and humoral immune responses. It is an important organ, but not a vital one, and its functions can be compensated by other lymphatic system organs and the liver.
The spleen is an intraperitoneal organ which means it is surrounded by the peritoneum, except at the spleen’s hilum. The spleen is located in the left upper quadrant and partly in the epigastrium. It lies posterior to the fundus of the stomach and anterior to the left hemidiaphragm at the level of ribs nine to eleven. On the spleen’s medial side lies the left kidney and adrenal gland but on the lateral side - the ribcage and muscles. Superior to it is the diaphragm, and inferiorly is the left colic flexure, also known as the splenic flexure. The spleen anatomy consists of surfaces, edges, and ends.
The spleen has two primary surfaces - diaphragmatic and visceral surface.
The diaphragmatic surface is smooth, a little bit irregular, and slightly convex. It is in contact with the inferior surface of the diaphragm’s costal part and the ribcage. There are impressions from ribs nine to eleven on it.
The visceral surface of the spleen is directed medially and is in contact with the other abdominal organs such as the colon, stomach, pancreas, left kidney, and the left adrenal gland. It is concave and has impressions created by the mentioned organs. In the middle of the visceral surface is located the hilum of the spleen, which is the site through which blood vessels, nerves, and lymph vessels pass. It is also a site that the visceral peritoneum does not cover.
The anterior part of the spleen’s visceral surface connects with the left colic flexure. This site is called the colic area.
The visceral surface faces the stomach’s fundus between the splenic hilum and the superior edge, and this site is called the gastric region. Under the splenic hilum, the tail of the pancreas touches the spleen’s visceral surface, and this site is called the pancreatic area.
The posterior part of the visceral surface connects with the left kidney and left adrenal gland. Those sites are called renal and suprarenal regions.
The spleen has two edges or borders and two ends or extremities. The superior edge is sharp with notches and is directed suprio-anteriorly, typically located at the level of the ninth rib.
The inferior border is relatively round and has an inferioposterior direction, located at the eleventh rib level. The anterior end is more expanded than the posterior.
Spleen varies in shape and size depending on a person’s gender, weight, and length, but usually, it has a fist, shoe, and oval-like form. Its average length is 12-14 cm (4.7-5.5 inches), its width varies from 8 to 10 cm (3-3.9 inches), but its thickness is 3-4 centimeters (1.1-1.6 inches). Spleen weighs 140 - 200 grams (4.9-7 oz). However, it is hard to palpate the spleen in a healthy individual; the doctor can palpate it at the left costal arch or above it through the anterolateral abdominal wall. An enlarged spleen is called splenomegaly, and in case of this condition, it is easy to palpate it below the left costal arch.
The spleen is surrounded by a connective tissue capsule containing elastic fibers, smooth muscles, and dense fibrous tissue. It has a protective purpose, and it helps the organ to remain in place. At the same time, it is capable of increasing in size significantly. Capsule fits very snugly to the splenic parenchyma, and it is called a fibrous capsule and is covered by a serous membrane from all sides.
Spleen is connected to three ligaments originating from the surrounding structures and peritoneum. One more ligament is not directly connected to the spleen but plays an essential role in the fixation.
The spleen is fixed in its place by the splenic ligaments, the surrounding organs, and the intra-abdominal pressure.
The spleen is very vascular and reddish-purple by color. The splenic parenchyma is called the pulp, and it divides into white and red pulp. Many septa called trabeculae fromed by fibroelastic tissue capsule extend into the pulp, dividing the spleen into segments. The tissue of the trabeculae and capsule contains myoepithelial cells that allow muscle contractions. These contractions help pump the blood into the circulatory system when in need, as the spleen is the organ that stores and contains a massive amount of blood.
White pulp is formed by lymphatic tissue mainly made up of white blood cells located around blood vessels as a longitudinal formation and round nodes. It is the central lymphoid tissue part of the spleen. The white pulp provides several functions of the spleen.
The white pulp has an essential role in the immune response to antigens as it is rich in T-lymphocytes, macrophages, and naive B-lymphocytes. These cells provide a normal immune response by plasma cell formation. The white pulp also plays an essential part in dealing with encapsulated bacteria.
The spleen consists mainly of the red pulp (around 80%), and the marginal zone separates it from the white pulp. The red pulp also takes part in providing splenic functions. The red pulp is rich in macrophages and venous sinuses (blood-filled cavities), and cords. The red pulp’s primary functions are removing old and damaged red blood cells and antigens, phagocytosis of bacteria. It also stores red blood cells in case of emergency conditions such as hypovolaemia.
The spleen is a very vascular organ, as mentioned before, with a substantial vascular network providing the arterial supply and lymphatic and venous drainage. The innervation of this organ is provided sympathetic and parasympathetic nerves of the autonomic nervous system.
The spleen’s main arterial supply is provided by the splenic artery from the coeliac trunk, a branch of the abdominal aorta. It is connected to the spleen via the splenorenal ligament.
The venous drainage is provided by the splenic vein that carries collected blood to the hepatic portal vein via the inferior mesenteric vein. At the level of the neck of the pancreas, the inferior mesenteric vein connects with the superior one.
The splenic lymph nodes are located at the splenic hilum. These lymph nodes receive lymph via the perivascular and subcapsular lymphatic vessels. Next, the lymph drains to pancreaticosplenic lymph nodes located on the superior surface of the pancreas. From there, the lymph drains to the coeliac lymph nodes.
The spleen is innervated by the nerves from the splenic plexus which is a part of the coeliac plexus. The splenic plexus nerves go through the splenic hilum together with arteries and veins.
Splenomegaly is a condition characterized by an enlarged spleen by weight or size affecting the normal spleen functions and causing abnormal spleen anatomy. The size or weight of an enlarged spleen can vary depending on gender, weight, and height. For example, usually, men, heavier and taller individuals have larger spleen compared to others. If the spleen is enormous than it should be, it is easy to palpate it below the left costal arch.
Many conditions cause splenomegaly, and it can be only a temporary condition regarding the reason and treatment.
Factors causing enlarged spleen are acute or chronic parasitic (malaria), viral (mononucleosis or Epstein-Barr virus, HIV) and bacterial (syphilis, tuberculosis) infections, liver diseases such as cirrhosis or hepatitis. Other possible causes are hemolytic anemias and a wide range of blood cancers (leukemias and lymphomas). Also, splenomegaly can be caused by blood clots or high pressure in the spleen and liver veins. Few more causes are various metabolic disorders, connective tissue diseases, and systemic diseases (lupus).
The symptoms of splenomegaly depend on the size of the spleen. If there is no significant increase in its size, it can present without any symptoms. An enlarged spleen can be found by accident on a routine examination basis during the physical or radiographical examination. But splenomegaly can present as pain or feeling of fullness in the left upper quadrant, sometimes spreading to the left shoulder. An enlarged spleen causes anemia, and an individual can more easily become sick and get various and frequent infections. With an enlarged spleen, there can be easy bruising and delayed bleeding in case of traumas or injuries. Also, individuals can feel fatigued all the time. An enlarged spleen can present as feeling full without eating, or it is hard to eat huge portions as a spleen can press on the stomach. The treatment includes dealing with the underlying cause and protecting the person from complications such as infections or spleen rupture.
Splenectomy is a surgery performed to remove the spleen. In other words, it is the spleen removal performed when there is abnormal spleen anatomy or spleen functions caused by many factors.
The most common reason for splenectomy is a ruptured spleen, most often caused by abdominal traumas and injuries. Rupture often happens as a complication in splenomegaly. As the spleen is an important organ, but not a vital one, its functions can compensate other lymphatic system organs and the liver. Spleen removal can be performed in severe hematologic disorders and cancers, infections resulting in abscesses, and spleen cysts. All those mentioned causes affect normal spleen anatomy and spleen functions.
In general, surgery is very safe and often done by a minimally invasive laparoscopic approach, which means several small incisions. The recovery time is pretty fast, usually without any significant problems. The bigger the spleen, the most likely a surgeon will perform the open splenectomy with one large incision.
Also, in spleen rupture, the first choice will be open spleen removal surgery. Infections, injury of other near organs, blood clots, and bleeding are the most common complications in surgery and after it. Allograft spleen transplantation exists, although it is not as common as, for example, heart transplantation.
People can live without a spleen and can be active in daily life after a successful recovery. The person needs to be more precautious by avoiding contact with sick people, washing hands more often, and being careful when traveling to places where it is possible to get serious infections, such as malaria in Nigeria. In the long term, there won’t be any dramatic changes in diet either. Still, a person can improve immune system's functions and overall health and reduce the risk of infections by eating more healthy and not consuming alcohol. After spleen removal, other organs take over spleen functions, such as the liver, bone marrow, and lymph nodes. As the spleen helps fight against various infections, persons with performed splenectomy are at higher risk of getting them. That is why people with spleen removal get vaccines against influenza and pneumococci. Also, usually, they should get vaccinated against meningococci and Haemophilus influenza type b infections.
The spleen is a secondary lymphoid organ and the largest organ of the lymphatic system.
The spleen is the largest and highly vascular organ of the lymphatic system located in the left upper quadrant and partly in the epigastrium.
The spleen lies in the left upper quadrant of the abdomen and partly in the epigastrium. It is located posterior to the fundus of the stomach and anterior to the left hemidiaphragm at the level of ribs nine to eleven.
No, it is not. The spleen is a part of the lymphatic system.
Yes, it does destroy the red blood cells. It is one of the main functions of the spleen.
Yes, as a lymphatic system organ, one of the functions of the spleen is to take part in the immune response to antigens.
The spleen has several functions, but primary spleen functions are immune response and blood filtration.
The spleen is made of red and white pulp and connective tissue. The white pulp is lymphatic tissue mainly made up of white blood cells, while the red pulp is mainly formed by venous sinuses and cords.
You do it by palpation, but it is hard to palpate the spleen in a healthy individual, even for a doctor. Anyway, palpate it through the anterolateral abdominal wall at the left costal arch or above it.
Splenomegaly can present without any symptoms, but also enlarged spleen can present as pain or feeling of fullness in the left upper quadrant of the abdomen, sometimes spreading even to the left shoulder. An enlarged spleen can cause anemia. An individual can feel very tired all the time. People with splenomegaly can more easily become sick and get various and frequent infections. With an enlarged spleen, you can see easy and continuing bleeding in case of traumas or injuries. An enlarged spleen can present as feeling full without eating, or it is hard to eat huge portions as the spleen can press on the stomach.
There are no known natural treatments for splenomegaly.
Yes, you can live without a spleen. Spleen removal surgery is known as splenectomy.
Spleen is an important but not a vital organ. Spleen functions can be compensated by other lymphatic system organs or the liver, for example.
After splenectomy, the splenic functions are provided by the liver, bone marrow, and lymph nodes.
No, the spleen does not have regeneration ability.
Yes, you can. After splenectomy, the body can fight infections without the spleen, as it is just a part of the immune system. Other elements, such as lymph nodes, help to protect the body against antigens.
After splenectomy, other organs take over the spleen functions. A person can live everyday life, but there is an increased risk of getting various infections, so healthcare professionals recommend several vaccinations.
As long as people are precautious of infections and get vaccines, they can live as long as others after splenectomy.
In the long term, there won’t be any dramatic changes in diet after splenectomy. Still, a person can improve how their immune system works and their overall health, also reducing the risk of infections by eating more healthy and by not consuming alcohol.
A person can live a healthy and long life without a spleen, as long as being precautious of infections and getting vaccines.
Spleen removal impacts the work of the immune system, however, spleen functions after splenectomy are taken over by other organs.
Allograft spleen transplantation exists, although it is not as common as heart transplantation, for example.