The splenic artery is one of the three main branches of the celiac trunk, which arises from the abdominal aorta. It is responsible for supplying blood to the spleen, as well as to parts of the stomach and pancreas.
Location
The splenic artery originates from the celiac trunk, usually at the level of the first lumbar vertebra (L1). From its origin, it runs along the upper border of the pancreas, following a tortuous or winding course toward the spleen, which is located in the upper left quadrant of the abdomen. The artery travels posterior to the stomach and is typically situated within the retroperitoneal space. Before reaching the spleen, the artery gives off several branches, including the short gastric arteries and the left gastroepiploic artery, which supply the stomach, as well as pancreatic branches that nourish the pancreas.
Anatomy
Origin
The splenic artery arises from the celiac trunk, which is one of the first major branches of the abdominal aorta. The celiac trunk originates at the level of the first lumbar vertebra (L1) just below the diaphragm. The splenic artery is one of the three primary branches of the celiac trunk, alongside the left gastric artery and the common hepatic artery.
Course
After originating from the celiac trunk, the splenic artery takes a tortuous or winding course along the upper border of the pancreas. It runs horizontally to the left, toward the spleen, traveling in the retroperitoneal space of the upper abdomen. The artery is located posterior to the stomach and anterior to the left kidney as it travels through the splenorenal ligament, a fold of peritoneum that connects the spleen to the left kidney.
As it approaches the spleen, the artery continues to follow a winding path, which is a distinctive feature of the splenic artery.[8] This tortuosity is thought to help accommodate the movement and expansion of the organs it supplies, such as the spleen and stomach. The artery enters the hilum of the spleen, where it divides into several terminal branches that supply the spleen.
Branches
Along its course, the splenic artery gives rise to several important branches that supply adjacent organs:
- Pancreatic Branches: The splenic artery gives off numerous small branches to the pancreas, known as the pancreatic branches. These branches supply the body and tail of the pancreas and include the largest pancreatic branch, the dorsal pancreatic artery, which runs along the posterior surface of the pancreas.
- Short Gastric Arteries: These small arteries arise from the distal part of the splenic artery near the hilum of the spleen. The short gastric arteries travel upward to supply the fundus of the stomach, running within the gastrosplenic ligament.
- Left Gastroepiploic Artery: This artery arises from the splenic artery just before it reaches the spleen. The left gastroepiploic artery travels along the greater curvature of the stomach, supplying blood to the stomach and the greater omentum, and eventually anastomoses with the right gastroepiploic artery, a branch of the gastroduodenal artery.[7]
- Terminal Splenic Branches: Upon reaching the hilum of the spleen, the splenic artery divides into multiple terminal branches, which penetrate the spleen and provide its blood supply. These branches supply the parenchyma of the spleen and are responsible for oxygenating the splenic tissue.
Relations
- Anteriorly: The splenic artery lies behind the stomach, specifically the body of the stomach. The artery runs along the posterior aspect of the lesser sac, a peritoneal cavity between the stomach and pancreas.
- Posteriorly: It is related to the upper part of the left kidney and adrenal gland. The artery also lies in close proximity to the left diaphragmatic crus, a muscular extension of the diaphragm.
- Inferiorly: The splenic artery lies superior to the body and tail of the pancreas, sending branches to supply these regions. The artery is often embedded within the pancreatic tissue as it follows the pancreas’ upper border.
- Superiorly: The artery runs near the diaphragm and beneath the left dome of the diaphragm as it approaches the spleen.
Length and Diameter
The splenic artery is one of the largest branches of the celiac trunk. Its length can vary between individuals, but it typically measures around 10-15 cm long, depending on the degree of tortuosity in its course.[6] The artery’s diameter also varies but is generally around 4-6 mm.
Termination
The splenic artery terminates by dividing into several branches that supply the spleen. These terminal branches enter the hilum of the spleen and further subdivide to penetrate the splenic parenchyma, ensuring that the entire organ receives an adequate blood supply. The artery may divide into superior and inferior branches before reaching the spleen, which then branch further within the splenic tissue.
Anatomical Variations
- Tortuosity: One of the hallmark features of the splenic artery is its tortuous course, which can vary greatly in different individuals. Some individuals have more pronounced tortuosity, while in others, the artery may follow a relatively straighter path.
- Origin Variations: In rare cases, the splenic artery may have variations in its origin. For instance, it may arise directly from the aorta rather than from the celiac trunk, or it may have an accessory splenic artery.
- Branching Patterns: The branching pattern of the splenic artery can also vary. Some individuals may have additional branches supplying the stomach or pancreas, or the artery may divide earlier or later than usual.
Function
The splenic artery plays a vital role in supplying blood to several organs in the upper abdomen, including the spleen, pancreas, and parts of the stomach. Its function ensures that these organs receive sufficient oxygen and nutrients to perform their metabolic and physiological roles effectively.[5] Below is a detailed breakdown of the splenic artery’s function according to the regions it supplies.
Blood Supply to the Spleen
The splenic artery is the primary artery responsible for delivering oxygenated blood to the spleen, which is essential for:
- Blood Filtration: The spleen filters old and damaged red blood cells from the bloodstream. The oxygen-rich blood provided by the splenic artery supports the metabolic processes needed for the spleen to function as a blood filtration organ.
- Immune Function: The spleen houses immune cells such as lymphocytes and macrophages, which help in detecting and fighting infections. The blood supply from the splenic artery ensures these immune cells receive the oxygen and nutrients required for immune responses, including the production of antibodies and removal of pathogens.
- Hematopoiesis (in certain conditions): In fetal development and certain adult conditions, the spleen functions as a site of blood cell production. The oxygen and nutrients supplied by the splenic artery support this process.
Blood Supply to the Pancreas
Through its pancreatic branches, particularly the dorsal pancreatic artery, the splenic artery provides blood to the body and tail of the pancreas. The artery supports both the endocrine and exocrine functions of the pancreas:
- Endocrine Function: The pancreas secretes hormones such as insulin and glucagon, which are crucial for regulating blood sugar levels.[4] The blood supplied by the splenic artery ensures that the islets of Langerhans, where these hormones are produced, receive the necessary oxygen and nutrients to function properly.
- Exocrine Function: The pancreas also produces digestive enzymes (amylase, lipase, and proteases) that are released into the small intestine. The blood from the splenic artery supports the pancreatic acinar cells, which are responsible for producing these enzymes, ensuring proper digestion and nutrient breakdown.
Blood Supply to the Stomach
The splenic artery provides blood to portions of the stomach through the short gastric arteries and the left gastroepiploic artery, playing a key role in maintaining the health of the gastric mucosa and supporting digestion:
- Maintenance of Gastric Mucosa: The short gastric arteries supply the fundus of the stomach, while the left gastroepiploic artery supplies the greater curvature. These areas of the stomach are involved in secreting mucus and bicarbonate, which protect the stomach lining from the corrosive effects of stomach acid. The oxygen and nutrients delivered by the splenic artery support the production and maintenance of this protective mucosal layer.
- Gastric Motility and Secretion: The blood supplied by the splenic artery ensures that the stomach muscles have the energy to perform peristalsis, the coordinated contractions that churn food and mix it with gastric juices. The artery also supports the production of stomach acid (hydrochloric acid) and digestive enzymes, which break down food into a form that can be absorbed in the intestines.
Support for Collateral Circulation
The splenic artery is a key player in establishing collateral circulation within the abdominal cavity, forming connections with other arteries to ensure uninterrupted blood flow even if one vessel is compromised:
- Anastomosis with the Right Gastroepiploic Artery: The left gastroepiploic artery, a branch of the splenic artery, anastomoses with the right gastroepiploic artery, forming a vascular network along the greater curvature of the stomach.[3] This anastomotic network ensures the stomach continues to receive blood even if one artery is damaged or obstructed.
- Pancreatic Collateral Circulation: The dorsal pancreatic artery (a branch of the splenic artery) anastomoses with the superior pancreaticoduodenal artery, creating a secondary blood supply for the pancreas. This redundancy is critical in maintaining pancreatic blood flow if other arteries are compromised.
Oxygen and Nutrient Delivery
As with all arteries, the primary function of the splenic artery is to deliver oxygen and nutrients to the tissues it supplies. This includes:
- Cellular Metabolism: The oxygen-rich blood supplied by the splenic artery supports the high metabolic demands of the spleen, pancreas, and stomach. These organs rely on a constant supply of oxygen for cellular respiration, energy production, and carrying out their specialized functions.
- Tissue Repair and Maintenance: The organs supplied by the splenic artery undergo regular wear and tear. For example, the gastric mucosa is constantly exposed to the acidic environment of the stomach, requiring continuous repair and regeneration. The blood flow from the splenic artery supports tissue repair and the maintenance of healthy cellular function.
Clinical Significance
The splenic artery is clinically significant due to its essential role in supplying blood to the spleen, pancreas, and stomach.[2] Its tortuous course along the upper border of the pancreas makes it prone to injury during abdominal surgeries, especially in procedures involving the pancreas, stomach, or spleen, such as splenectomy or pancreatic surgery.
The splenic artery is also a common site for aneurysms, known as splenic artery aneurysms, which can rupture and lead to life-threatening internal bleeding. Splenic artery aneurysms are more common in conditions like portal hypertension and pregnancy, requiring careful monitoring or surgical intervention.
In pancreatic diseases, such as pancreatitis or pancreatic cancer, the proximity of the splenic artery to the pancreas makes it susceptible to compression or invasion by tumors, which can affect its blood flow. Additionally, during gastric surgeries, the artery’s branches supplying the stomach, such as the left gastroepiploic artery, need to be carefully managed to prevent ischemic complications in the stomach.
