The duodenojejunal flexure or duodenojejunal junction is the border between 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 ...

and the

jejunum The jejunum is the second part of the small intestine in humans and most higher vertebrates, including mammals, reptiles, and birds. Its lining is specialised for the absorption by enterocytes of small nutrient molecules which have been previou ...

Structure

The ascending portion of the

ascends on the left side of the

aorta The aorta ( ) is the main and largest artery in the human body, originating from the left ventricle of the heart and extending down to the abdomen, where it splits into two smaller arteries (the common iliac arteries). The aorta distributes o ...

, as far as the level of the upper border of the second

lumbar vertebra The lumbar vertebrae are, in human anatomy, the five vertebrae between the rib cage and the pelvis. They are the largest segments of the vertebral column and are characterized by the absence of the foramen transversarium within the transverse ...

. At this point, it turns abruptly forward to merge with the

, forming the duodenojejunal flexure. This forms the beginning of the jejunum. The duodenojejunal flexure is surrounded by the

suspensory muscle of the duodenum The suspensory muscle of duodenum is a thin muscle connecting the junction between the duodenum, jejunum, and duodenojejunal flexure to connective tissue surrounding the superior mesenteric artery and coeliac artery. It is also known as the lig ...

. It is

retroperitoneal The retroperitoneal space (retroperitoneum) is the anatomical space (sometimes a potential space) behind (''retro'') the peritoneum. It has no specific delineating anatomical structures. Organs are retroperitoneal if they have peritoneum on thei ...

, so is less mobile than the jejunum that comes after it, helping to stabilise the jejunum. The duodenojejunal flexure lies in front of the left

psoas major muscle The psoas major ( or ; from grc, ψόᾱ, psóā, muscles of the loins) is a long fusiform muscle located in the lateral lumbar region between the vertebral column and the brim of the lesser pelvis. It joins the iliacus muscle to form the il ...

, the left renal artery, and the

left renal vein The renal veins are large-calibre veins that drain blood filtered by the kidneys into the inferior vena cava. There is one renal vein draining each kidney. Because the inferior vena cava is on the right half of the body, the left renal vein is lo ...

. It is covered in front, and partly at the sides, by

peritoneum The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal (or coelomic) organs, and is composed of a layer of mes ...

continuous with the left portion of the

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 intesti ...

Clinical significance

The

ligament of Treitz The suspensory muscle of duodenum is a thin muscle connecting the junction between the duodenum, jejunum, and duodenojejunal flexure to connective tissue surrounding the superior mesenteric artery and coeliac artery. It is also known as the li ...

, a peritoneal fold, from the

right crus of diaphragm The crus of diaphragm (pl. crura), refers to one of two tendinous structures that extends below the diaphragm to the vertebral column. There is a right crus and a left crus, which together form a tether for muscular contraction. They take their ...

, is an identification point for the duodenojejunal flexure during

abdominal surgery The term abdominal surgery broadly covers surgical procedures that involve opening the abdomen ( laparotomy). Surgery of each abdominal organ is dealt with separately in connection with the description of that organ (see stomach, kidney, liver, ...

.Jacob, S. (2007) Chapter 4: Abdomen; Human anatomy, A clinically-orientated approach.

Additional images

File:Gray1042.png, Duodenojejunal fossa. File:Gray1225.png, Front of abdomen, showing surface markings for

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 ...

, and

kidneys The kidneys are two reddish-brown bean-shaped organs found in vertebrates. They are located on the left and right in the retroperitoneal space, and in adult humans are about in length. They receive blood from the paired renal arteries; bloo ...

References

External links

* - "The large intestine." * - "Intestines and Pancreas: The Duodenum" * {{Authority control Digestive system

Structure

Clinical significance

Additional images

See also

References

External links