The uncinate process is a small part of the

pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an end ...

. The uncinate process is the formed prolongation of the angle of junction of the lower and left lateral borders in the

head of the pancreas The pancreas is an organ of the digestive system and endocrine system of vertebrates. In humans, it is located in the abdomen behind the stomach and functions as a gland. The pancreas is a mixed or heterocrine gland, i.e. it has both an endoc ...

. The word "uncinate" comes from the Latin "uncinatus", meaning "hooked".

Structure

Development

The pancreas arises as two separate bodies, the dorsal pancreas and the ventral pancreas. The dorsal pancreas appears first, at around day 26, opposite the developing

hepatic duct The common hepatic duct is the first part of the biliary tract. It joins the cystic duct coming from the gallbladder to form the common bile duct. Structure The common hepatic duct is the first part of the biliary tract. It is formed by the c ...

, and grows into the

dorsal mesentery The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestin ...

. The ventral pancreas develops at the junction of the hepatic duct and the rest of the

foregut The foregut is the anterior part of the alimentary canal, from the mouth to the duodenum at the entrance of the bile duct. Beyond the stomach, the foregut is attached to the abdominal walls by mesentery. The foregut arises from the endoderm, deve ...

. During development, differential growth of the wall of the

stomach The stomach is a muscular, hollow organ in the gastrointestinal tract of humans and many other animals, including several invertebrates. The stomach has a dilated structure and functions as a vital organ in the digestive system. The stomach i ...

causes it to rotate to the left, and the

liver The liver is a major Organ (anatomy), organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the Protein biosynthesis, synthesis of proteins and biochemicals necessary for ...

and stomach undergo a lot of growth. This makes the two parts of the pancreas rotate around the

duodenum The duodenum is the first section of the small intestine in most higher vertebrates, including mammals, reptiles, and birds. In fish, the divisions of the small intestine are not as clear, and the terms anterior intestine or proximal intestine m ...

. They then fuse; the dorsal pancreatic bud becomes the

body Body may refer to: In science * Physical body, an object in physics that represents a large amount, has mass or takes up space * Body (biology), the physical material of an organism * Body plan, the physical features shared by a group of anima ...

tail The tail is the section at the rear end of certain kinds of animals’ bodies; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, r ...

, and isthmus of the pancreas. The isthmus (also called the central pancreas) is the region of the gland that runs anterior to the superior mesenteric artery; by convention, it divides the right and left sides of the pancreas. The ventral pancreatic bud forms the pancreatic head and uncinate process. The glands continue to develop but the duct systems anastomose. The main pancreatic duct is formed by the fusion of the dorsal and ventral pancreas. The embryology also explains the strange zig-zag course of the main

pancreatic duct The pancreatic duct, or duct of Wirsung (also, the major pancreatic duct due to the existence of an accessory pancreatic duct), is a duct joining the pancreas to the common bile duct. This supplies it with pancreatic juice from the exocrine pancre ...

and the occasional appearance of an

accessory pancreatic duct The pancreatic duct, or duct of Wirsung (also, the major pancreatic duct due to the existence of an accessory pancreatic duct), is a duct joining the pancreas to the common bile duct. This supplies it with pancreatic juice from the exocrine pancre ...

. The uncinate process, unlike the remainder of the organ, passes posteriorly to the

superior mesenteric vein In human anatomy, the superior mesenteric vein (SMV) is a blood vessel that drains blood from the small intestine (jejunum and ileum). Behind the neck of the pancreas, the superior mesenteric vein combines with the splenic vein to form the hepati ...

(it can pass posteriorly to the

superior mesenteric artery In human anatomy, the superior mesenteric artery (SMA) is an artery which arises from the anterior surface of the abdominal aorta, just inferior to the origin of the celiac trunk, and supplies blood to the intestine from the lower part of the ...

, but this is less common).

Clinical significance

Sometimes the pancreas fails to develop normally and there may be congenital defects associated with the uncinate process. The uncinate process may split and encircle the duodenum, which is known as an

annular pancreas Annular pancreas is a rare condition in which the second part of the duodenum is surrounded by a ring of pancreatic tissue continuous with the head of the pancreas. This portion of the pancreas can constrict the duodenum and block or impair the fl ...

.Drake et al, ''Gray's Anatomy for Students'', Churchill Livingstone/Elsevier (2010), 2nd edition, chapter 4 There is also a common condition called

pancreas divisum Pancreatic divisum is a congenital anomaly in the anatomy of the ducts of the pancreas in which a single pancreatic duct is not formed, but rather remains as two distinct dorsal and ventral ducts. Most individuals with pancreas divisum remain with ...

where the dorsal and ventral pancreas do not fuse properly.

References

External links

* - "The Pancreas" * - "The duodenum and pancreas." * {{DEFAULTSORT:Uncinate Process Of Pancreas Pancreas anatomy