Tail of Pancreas
The tail of the pancreas is the narrow left extremity of the pancreas extending from the body toward the hilum of the spleen. Unlike most of the pancreas, it lies within the splenorenal ligament and is closely related to the splenic vessels, left kidney, and spleen.
The tail of the pancreas is the narrow, leftmost portion of the pancreas. It continues laterally from the body of the pancreas and extends toward the hilum of the spleen. It is the most mobile part of the pancreas and has a distinctive peritoneal relationship compared with the head, neck, and body.
Most of the pancreas is secondarily retroperitoneal, but the pancreatic tail extends within the splenorenal ligament, also called the lienorenal ligament, as it approaches the spleen. This places the tail in close anatomical relationship with the splenic artery, splenic vein, left kidney, and splenic hilum.
The tail contains exocrine pancreatic tissue, endocrine pancreatic islets, branches of the pancreatic ductal system, blood vessels, lymphatics, and autonomic nerves. Its intimate relationship with the splenic vessels and spleen is particularly important during distal pancreatic surgery.
Location
The tail is located in the left upper abdomen and represents the terminal portion of the pancreas.
It extends from the pancreatic body toward the spleen, generally passing anterior to the upper part of the left kidney.
Position Within the Pancreas
The pancreas is conventionally divided into:
- Head
- Uncinate process
- Neck
- Body
- Tail
The tail forms the narrow lateral continuation of the body and terminates near the splenic hilum.
Shape of the Pancreatic Tail
The pancreatic tail is usually narrower than the body and gradually tapers as it extends toward the spleen.
Its exact length, thickness, and relationship to the splenic hilum vary between individuals.
Relationship to the Body
The tail is directly continuous with the body of the pancreas.
There is no sharply defined external anatomical boundary between the body and tail, and the distinction is primarily descriptive.
Relationship to the Spleen
The pancreatic tail extends toward the hilum of the spleen.
Its tip may closely approach or contact the splenic hilum, making the spleen an important landmark when identifying the distal pancreas.
Splenic Hilum
The splenic hilum is the region on the visceral surface of the spleen where splenic vessels, lymphatics, and nerves enter or leave the organ.
The pancreatic tail approaches this region together with the splenic vascular structures.
Relationship to the Left Kidney
The tail lies anterior to the left kidney, particularly its upper portion.
This relationship is important on cross-sectional imaging and during retroperitoneal or pancreatic surgical procedures.
Relationship to the Left Suprarenal Gland
The left suprarenal gland lies posterior and medial to the distal pancreatic region.
The exact relationship varies with pancreatic morphology and the position of surrounding retroperitoneal structures.
Relationship to the Stomach
The stomach lies anterior to the body and tail of the pancreas.
The lesser sac intervenes between the stomach and much of the anterior pancreatic surface.
Lesser Sac
The lesser sac, or omental bursa, lies posterior to the stomach and anterior to the pancreas.
Inflammatory fluid arising from the distal pancreas can therefore extend into this peritoneal recess.
Relationship to the Left Colic Flexure
The left colic flexure lies inferior to the region of the pancreatic tail and spleen.
Its position can vary, but it represents an important neighboring structure during surgery and imaging.
Relationship to the Transverse Mesocolon
The transverse mesocolon is attached along the anterior aspect of the pancreas and continues laterally toward the left upper abdomen.
The distal pancreatic region is therefore closely associated with the transition between supracolic and infracolic abdominal compartments.
Splenorenal Ligament
The splenorenal ligament is a double layer of peritoneum extending between the spleen and the posterior abdominal wall in the region of the left kidney.
It contains the splenic vessels and the tail of the pancreas.
Contents of the Splenorenal Ligament
Important structures associated with the splenorenal ligament include:
- Tail of the pancreas
- Splenic artery and its terminal branches
- Splenic vein and its tributaries
- Lymphatic vessels
- Autonomic nerve fibers accompanying the vessels
Peritoneal Relationship
The tail differs from most of the remainder of the pancreas because it extends within the splenorenal ligament.
This gives the distal pancreas a more intraperitoneal relationship than the secondarily retroperitoneal head, neck, and body.
Clinical Importance of the Peritoneal Relationship
The position of the tail within the splenorenal ligament is particularly important during operations involving the spleen.
Because the pancreatic tail may lie close to the splenic hilum, it can be injured during difficult splenic dissection.
Relationship to the Splenic Artery
The splenic artery follows a characteristically tortuous course along the superior border of the pancreatic body and tail.
As it approaches the spleen, it divides into terminal branches near the splenic hilum.
Relationship to the Splenic Vein
The splenic vein runs along the posterior aspect of the pancreatic body and tail.
It receives numerous small pancreatic tributaries along its course.
Distal Splenic Vessels
Near the pancreatic tail, the splenic artery and vein approach the splenic hilum and become closely associated with the distal pancreatic tissue.
This close relationship is a major consideration in distal pancreatectomy and spleen-preserving surgery.
Pancreatic Parenchyma
The tail is composed of lobulated pancreatic tissue containing exocrine acini, ductal structures, pancreatic islets, connective tissue, blood vessels, lymphatics, and nerves.
Exocrine Tissue
The majority of pancreatic tissue consists of exocrine acini.
Acinar cells synthesize digestive enzymes that are released into small ducts and ultimately enter the main pancreatic duct.
Pancreatic Islets
The endocrine component of the pancreatic tail consists of pancreatic islets, or islets of Langerhans.
Islets are distributed throughout the pancreas, with a relatively greater concentration toward the body and tail than in some other pancreatic regions.
Endocrine Cells
Pancreatic islets contain several endocrine cell populations, including beta cells, alpha cells, delta cells, and pancreatic polypeptide-producing cells.
These cells release hormones directly into the rich capillary network of the islets.
Main Pancreatic Duct
The main pancreatic duct, or duct of Wirsung, generally begins in the region of the pancreatic tail and extends through the body toward the head.
Numerous small ducts join it as it passes through the gland.
Ductal Drainage of the Tail
Small intralobular and interlobular ducts collect secretions from exocrine acini within the tail.
These ducts converge toward larger tributaries and ultimately drain into the main pancreatic duct.
Direction of Pancreatic Secretion
Exocrine secretions produced within the tail travel medially through the ductal system toward the pancreatic head.
They ultimately enter the duodenum through the major pancreatic drainage pathway.
Arterial Supply
The tail receives arterial blood primarily from pancreatic branches of the splenic artery.
Several named and unnamed branches may participate in the arterial supply of the distal pancreas.
Splenic Artery
The splenic artery is one of the major branches of the celiac trunk.
Its course along the superior border of the pancreas allows it to provide multiple branches to the pancreatic body and tail before reaching the spleen.
Great Pancreatic Artery
The great pancreatic artery, or pancreatica magna, usually arises from the splenic artery.
It supplies substantial portions of the body and tail and participates in intrapancreatic arterial anastomoses.
Caudal Pancreatic Artery
The caudal pancreatic artery is an important arterial branch supplying the pancreatic tail.
It commonly arises from the distal splenic artery or one of its terminal branches, although its anatomy is variable.
Dorsal Pancreatic Artery
Branches of the dorsal pancreatic artery may contribute to the vascular supply of the distal pancreas through anastomotic channels.
The origin and branching pattern of this vessel are variable.
Arterial Anastomoses
Pancreatic arteries form extensive anastomoses within and around the gland.
These communications help maintain perfusion of pancreatic tissue despite considerable variation in individual arterial anatomy.
Arterial Supply Summary
| Artery | Contribution |
|---|---|
| Splenic artery | Primary parent artery supplying distal pancreas |
| Great pancreatic artery | Supplies body and tail |
| Caudal pancreatic artery | Important supply to pancreatic tail |
| Dorsal pancreatic artery | May contribute through anastomotic branches |
Venous Drainage
Venous blood from the pancreatic tail drains predominantly through small pancreatic veins into the splenic vein.
The splenic vein ultimately contributes to formation of the hepatic portal vein.
Pancreatic Venous Tributaries
Numerous small veins drain directly from the distal pancreatic parenchyma into the splenic vein.
These vessels can be numerous and delicate, which is important during surgical mobilization of the pancreas.
Portal Venous System
Venous blood from the pancreatic tail ultimately enters the hepatic portal circulation.
This blood therefore passes through the liver before entering the systemic venous circulation.
Lymphatic Drainage
Lymphatic vessels from the tail generally accompany the splenic vessels toward pancreaticosplenic lymph nodes.
Drainage then proceeds toward lymph nodes associated with the celiac arterial system.
Pancreaticosplenic Lymph Nodes
The pancreaticosplenic nodes lie along the splenic vessels and receive lymph from the pancreatic body and tail.
They form an important regional lymphatic pathway for the distal pancreas.
Celiac Lymph Nodes
Lymph from pancreaticosplenic nodes can pass toward the celiac lymph nodes around the origin of the celiac trunk.
These nodes participate in drainage of several upper abdominal organs.
Innervation
The pancreatic tail receives autonomic innervation through nerve fibers accompanying its arterial supply.
These fibers originate from autonomic plexuses associated with the celiac and superior mesenteric regions.
Sympathetic Innervation
Sympathetic fibers reach the pancreas through abdominal autonomic plexuses.
Visceral afferent fibers carrying pain from pancreatic disease commonly accompany sympathetic pathways toward the spinal cord.
Parasympathetic Innervation
Parasympathetic fibers are derived primarily from the vagus nerve.
They contribute to neural regulation of pancreatic secretory activity.
Functions of the Pancreatic Tail
The pancreatic tail contributes to both the exocrine and endocrine functions of the pancreas.
Its acinar tissue produces digestive secretions, while its pancreatic islets release hormones into the bloodstream.
Exocrine Function
Exocrine acinar cells produce digestive enzymes and enzyme precursors.
Ductal cells contribute bicarbonate-rich fluid that assists in neutralizing acidic contents entering the duodenum.
Endocrine Function
Pancreatic islet cells produce hormones involved in regulation of blood glucose and metabolism.
Major pancreatic hormones include insulin, glucagon, somatostatin, and pancreatic polypeptide.
Tail of Pancreas on CT
On CT, the pancreatic tail is identified extending leftward from the body toward the splenic hilum.
The splenic vessels, left kidney, stomach, and spleen provide useful landmarks for locating the distal pancreas.
Tail of Pancreas on MRI
MRI can demonstrate the pancreatic tail, surrounding soft tissues, splenic vessels, and pancreatic ductal system.
Magnetic resonance cholangiopancreatography can further evaluate the main pancreatic duct and its branches.
Ultrasound
The pancreatic tail can be difficult to visualize completely with routine transabdominal ultrasound.
Overlying bowel gas, the depth of the distal pancreas, and its relationship with the stomach and spleen may limit visualization.
Endoscopic Ultrasound
Endoscopic ultrasound provides high-resolution imaging of the distal pancreas from within the stomach.
The close relationship between the posterior stomach and pancreatic body and tail makes this approach useful for evaluating small lesions.
Pancreatitis
Inflammation of the pancreas may involve the tail along with other portions of the gland.
Inflammatory changes can extend into adjacent retroperitoneal tissues, the lesser sac, and spaces around the spleen and left kidney.
Peripancreatic Fluid
Fluid arising from inflammation of the distal pancreas can track around the stomach, spleen, left kidney, and adjacent fascial planes.
The distribution of fluid reflects the anatomical relationships of the pancreatic tail.
Pancreatic Pseudocyst
A pancreatic pseudocyst may develop following pancreatitis or pancreatic duct disruption.
Collections arising from the body or tail can expand toward the lesser sac, stomach, spleen, or left retroperitoneum.
Pancreatic Tail Tumors
Both exocrine and endocrine neoplasms can arise within the pancreatic tail.
Distal pancreatic tumors have different anatomical effects from lesions of the pancreatic head because they are relatively distant from the terminal common bile duct.
Absence of Early Biliary Obstruction
Tumors confined to the pancreatic tail generally do not directly obstruct the distal common bile duct.
Consequently, biliary obstruction is less characteristic of an isolated tail lesion than of a lesion involving the pancreatic head.
Local Tumor Extension
As a tumor of the tail enlarges, it may involve neighboring structures such as the splenic vessels, spleen, stomach, left kidney, adrenal region, or retroperitoneal tissues.
Splenic Vein Involvement
The close relationship between the splenic vein and pancreatic tail makes the vein vulnerable to compression, inflammation, thrombosis, or tumor invasion.
Splenic Vein Thrombosis
Splenic vein thrombosis may occur in association with pancreatitis or pancreatic neoplasms involving the body and tail.
Obstruction of the splenic vein alters venous drainage from the spleen.
Left-Sided Portal Hypertension
Splenic vein obstruction can produce left-sided portal hypertension, also called sinistral portal hypertension.
Venous blood may be redirected through collateral pathways, including gastric venous channels.
Distal Pancreatectomy
Distal pancreatectomy is surgical removal of the distal portion of the pancreas and commonly includes the tail and a variable portion of the body.
The operation may be performed with or without removal of the spleen.
Distal Pancreatectomy With Splenectomy
The close association of the pancreatic tail with the splenic vessels can make removal of the spleen necessary in some distal pancreatic operations.
This is particularly relevant when disease involves the splenic vessels or splenic hilum.
Spleen-Preserving Distal Pancreatectomy
In selected cases, the distal pancreas can be removed while preserving the spleen.
Different surgical techniques either preserve the main splenic vessels or rely on alternative vascular pathways to maintain splenic perfusion.
Risk of Pancreatic Injury During Splenectomy
Because the pancreatic tail can extend very close to the splenic hilum, it is vulnerable during splenic surgery.
Unrecognized injury to the tail may damage pancreatic parenchyma or small pancreatic ducts.
Postoperative Pancreatic Fistula
Disruption of pancreatic ducts can permit enzyme-rich pancreatic fluid to escape from the gland.
A postoperative pancreatic fistula is therefore an important potential complication following distal pancreatic surgery or inadvertent injury to the tail.
Pancreatic Trauma
Traumatic injury to the distal pancreas may occur with significant blunt or penetrating abdominal trauma.
Assessment of the main pancreatic duct is particularly important because ductal disruption substantially influences management.
Accessory Spleen and Pancreatic Tail
Accessory splenic tissue may occur near the splenic hilum and pancreatic tail.
Occasionally, splenic tissue may be embedded within the pancreatic tail, producing an intrapancreatic accessory spleen.
Intrapancreatic Accessory Spleen
An intrapancreatic accessory spleen is a benign anatomical variant consisting of normal splenic tissue located within the pancreatic tail.
On imaging, it may resemble a pancreatic mass unless its imaging characteristics are recognized as similar to those of the spleen.
Tail Versus Body of Pancreas
| Feature | Tail | Body |
|---|---|---|
| Position | Leftmost pancreatic extremity | Central elongated portion |
| Continuation | Extends from body toward spleen | Extends from neck toward tail |
| Peritoneal relationship | Extends within splenorenal ligament | Predominantly secondarily retroperitoneal |
| Major organ relationship | Splenic hilum | Stomach and posterior abdominal wall |
| Major vascular relationships | Distal splenic vessels | Splenic artery and vein along superior and posterior aspects |
Tail Versus Head of Pancreas
| Feature | Tail | Head |
|---|---|---|
| Position | Left upper abdomen near spleen | Within duodenal curvature |
| Peritoneal relationship | Within splenorenal ligament near splenic hilum | Secondarily retroperitoneal |
| Major arterial supply | Branches of splenic artery | Pancreaticoduodenal arcades |
| Common bile duct relationship | Not closely related | Closely related |
| Major adjacent organ | Spleen | Duodenum |
Important Anatomical Relationships
| Structure | Relationship to Pancreatic Tail |
|---|---|
| Spleen | Tail approaches splenic hilum |
| Splenic artery | Courses along superior aspect and divides near spleen |
| Splenic vein | Closely related posteriorly |
| Left kidney | Posterior |
| Stomach | Anterior, largely separated by lesser sac |
| Left colic flexure | Inferior |
| Splenorenal ligament | Contains pancreatic tail and splenic vessels |
Key Features of the Pancreatic Tail
| Feature | Key Point |
|---|---|
| Location | Leftmost part of pancreas |
| Continuity | Continuation of pancreatic body |
| Terminal relationship | Approaches splenic hilum |
| Peritoneal relationship | Extends within splenorenal ligament |
| Major artery | Pancreatic branches of splenic artery |
| Major vein | Splenic vein |
| Duct | Main pancreatic duct begins in distal gland and travels medially |
| Lymphatic drainage | Pancreaticosplenic nodes toward celiac nodes |
| Posterior organ relationship | Left kidney |
| Surgical importance | Closely associated with spleen and splenic vessels |
Anatomical and Clinical Importance
The tail of the pancreas is the narrow distal portion of the gland extending from the pancreatic body toward the splenic hilum. Its location within the splenorenal ligament distinguishes it from the predominantly secondarily retroperitoneal remainder of the pancreas.
The tail is intimately related to the splenic artery and vein, left kidney, stomach, and spleen. Pancreatic branches of the splenic artery provide its principal arterial supply, while venous blood drains mainly into the splenic vein. Its lymphatic vessels predominantly follow the splenic vessels toward pancreaticosplenic and celiac lymph nodes.
These relationships are particularly important in pancreatitis, distal pancreatic tumors, splenic vein thrombosis, splenic surgery, and distal pancreatectomy. The proximity of the pancreatic tail to the splenic hilum also creates a risk of pancreatic injury during splenectomy, while anatomical variants such as an intrapancreatic accessory spleen can be important when interpreting pancreatic imaging.
Last updated on October 1, 2026