Duodenojejunal flexure
Encyclopedia
The duodenojejunal flexure or duodenojejunal junction is the border between the duodenum
and the jejunum
.
The ascending portion of the duodenum
ascends on the left side of the aorta
, as far as the level of the upper border of the second lumbar vertebra, where it turns abruptly forward to become the jejunum
, forming the duodenojejunal flexure.
It lies in front of the left Psoas major and left renal vessels, and is covered in front, and partly at the sides, by peritoneum
continuous with the left portion of the mesentery
.
The ligament of Treitz, a peritoneal fold, from the right crus of diaphragm, is an identification point for the duodenojejunal flexure at operation.
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 may be used instead of duodenum...
and the jejunum
Jejunum
The jejunum is the middle 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 middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...
.
The ascending portion of the duodenum
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 may be used instead of duodenum...
ascends on the left side of the aorta
Aorta
The aorta is the largest artery in the body, originating from the left ventricle of the heart and extending down to the abdomen, where it branches off into two smaller arteries...
, as far as the level of the upper border of the second lumbar vertebra, where it turns abruptly forward to become the jejunum
Jejunum
The jejunum is the middle 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 middle intestine or mid-gut may be used instead of jejunum.The jejunum lies between the duodenum...
, forming the duodenojejunal flexure.
It lies in front of the left Psoas major and left renal vessels, and is covered in front, and partly at the sides, by peritoneum
Peritoneum
The peritoneum is the serous membrane that forms the lining of the abdominal cavity or the coelom — it covers most of the intra-abdominal organs — in amniotes and some invertebrates...
continuous with the left portion of the mesentery
Mesentery
In anatomy, the mesentery is the double layer of peritoneum that suspends the jejunum and ileum from the posterior wall of the abdomen. Its meaning, however, is frequently extended to include double layers of peritoneum connecting various components of the abdominal cavity.-Mesentery :The...
.
The ligament of Treitz, a peritoneal fold, from the right crus of diaphragm, is an identification point for the duodenojejunal flexure at operation.