The Pancreas
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Gallbladder
and biliary ducts | Main Anatomy Index | Blood vessels of the abdomen and pelvis
Last updated 30 March 2006
The Pancreas
- The pancreas (G. pankreas, sweetbread; Fr. pas [pan], all + kreas,
flesh) is an elongated (12 to 15 cm), soft,
greyish-pink digestive gland.
- It is located in the transpyloric plane, more or less transversely across the posterior abdominal wall and posterior to the stomach.
- It is located in the epigastric and left
hypochondriac regions and its right part lies across the bodies of L1 to L3 vertebrae.
- The pancreas is both an exocrine and endocrine gland.
- It produces:
- Pancreatic juices that enters the duodenum via the pancreatic ducts;
- Internal secretions (glucagon and insulin) that enter
the blood.
- The pancreas has a head, neck,
body and tail.
- Its shape somewhat resemble an inverted, curved tobacco pipe.
- Its right side (head) lies inferior to the transpyloric
plane while the left side (tail) lies superior to it.
- The pancreas lies behind the omental bursa
where it forms a major part of the stomach bed.
The Head of the Pancreas
- This is located within the curve of the duodenum and is embraced by it.
- It has a prolongation, called the uncinate process (L.
hook-shaped).
- This extends superiorly and to the left
and lies posterior to the superior
mesenteric vessels.
- Here, it rests against the aorta posteriorly.
- The head rests posteriorly on the IVC,
right renal vessels, and the left
renal vein.
- The bile duct, on its way to
the duodenum, lies in a groove on the posterosuperior
surface of the head of the pancreas; sometimes it is embedded in it.
The Neck of the Pancreas
- It is about 2 cm long, is continuous with the head and merges imperceptibly into the body of the pancreas.
- The neck is grooved posteriorly by the superior mesenteric vessels.
- The superior mesenteric vein joins the splenic vein to form the portal vein
posterior to the neck of the pancreas.
The Body of the Pancreas
- This extends slightly superiorly as it extends to the left
across the aorta and the superior
lumbar vertebrae, posterior to the omental
bursa.
- The body is somewhat triangular in cross-section and
has three surfaces: anterior, posterior, and inferior.
- The body of the pancreas is intimately related to the splenic vein.
- Where it lies anterior to the aorta, the body lies between
the coeliac trunk and the superior
mesenteric artery.
- The body has a small projection, the omental tuberosity,
arising from the superior border, and contacting the lesser omentum.
- The tuberosity is located immediately inferior to the coeliac
trunk.
Anterior Surface of the
Pancreas
- This surface is covered with peritoneum and forms part of
the bed of the stomach.
- Here is provides attachment for the transverse
mesocolon.
Posterior Surface of the
Pancreas
- This is devoid of peritoneum where it is in contact with
the aorta, superior mesenteric
artery, left suprarenal gland, and the left kidney and vessels.
The Tail of the Pancreas
- This is its narrow left end and it may
be thick or blunted.
- It passes between the two layers of the splenorenal
(lienorenal) ligament with the splenic vessels.
- Its end usually contacts the hilum of the spleen.
The Pancreatic Ducts
The Main Pancreatic Duct
- When the main duct is joined by the parts of the duct in the head
and uncinate process, it becomes Y-shaped.
- Within the head, the main pancreatic duct turns inferiorly
and comes into close relationship with the bile duct.
- Usually, these two ducts unite to form the hepatopancreatic
ampulla (of Vater).
- The ampulla opens via a common duct into the duodenum at the
summit of the major duodenal papilla.
- The sphincter around the terminal part of the main pancreatic duct is known as the sphincter of the pancreatic duct.
- The sphincter around the hepatopancreatic ampulla is
called the hepatopancreatic sphincter (of Oddi), which
controls both the flow of pancreatic juices and bile.
The Accessory Pancreatic
Duct
- This drains part of the head of the pancreas.
- Usually, it is connected to the main pancreatic duct but in about 9% of people, it is a
completely separate duct.
- It opens into the duodenum at the minor
duodenal papilla.
Arterial Supply of
the Pancreas
- The arteries of the pancreas are derived from the splenic artery
and the pancreaticoduodenal arteries.
- The anterior and posterior
superior pancreaticoduodenal arteries (from gastroduodenal artery) and the anterior and posterior inferior
pancreaticoduodenal arteries (from the superior mesenteric artery) supply the head of the pancreas.
Venous Drainage of
the Pancreas
- The pancreatic veins drain into the portal, splenic, and superior mesenteric veins.
- Most of them empty into the splenic vein.
Lymphatic
Drainage of the Pancreas
- The lymph vessels of the pancreas follow the blood vessels.
- Most of them end in the pancreaticosplenic nodes that
lie along the splenic artery on the superior border of
the pancreas.
- Some vessels end in the pyloric lymph nodes.
- Efferent vessels from these nodes drain to the coeliac,
hepatic and superior mesenteric
lymph nodes.
Innervation of the Pancreas
- The nerves are derived form the vagus and the splanchnic nerves.
- The pain fibres are carried by the splanchnic
nerves.
- The sympathetic and parasympathetic
fibres reach the gland by passing along the arteries of the coeliac
and superior mesenteric plexuses.