The duodenum (duodenum) is the initial part of the small intestine, immediately following the stomach. The end of the duodenum is considered duodenal-jejunal flexure. The length of the intestine is 25–30 cm, with a diameter of about 5 cm. The duodenum covers the head of the pancreas in a horseshoe (fig). There are four parts of the duodenum. The upper part is a continuation of the pylorus of the stomach. Due to the sharp bend, it is clearly delimited from the next part; X-ray examination of the upper part of the duodenum has the form of a ball, and therefore it is also called the duodenal bulb. Next comes the descending part, continuing into the lower horizontal and ascending parts. Last goes to the jejunum. On the medial side of the descending part is located the large (fater) nipples of the duodenum - in this place the common bile duct and pancreatic duct open in it. Slightly above the large nipple of the duodenum is the small nipple, where there is the mouth of the additional pancreatic duct existing in some cases.
Topography of the duodenum: 1 - liver ; 2 - pancreas; 3, 4, 6 and 9 - ascending (3), lower (4), descending (6), upper (9) parts of the duodenum; 5 - large nipple of the duodenum; 7 - longitudinal fold; 8 - small nipple of the duodenum; 10 - common bile duct.
Blood supply of the duodenum is common with the head of the pancreas and is carried out by the branches of the celiac trunk and superior mesenteric artery. Vein of the duodenum fall into the portal vein.
The duodenum is innervated by branches of the celiac and superior mesenteric plexus and vagus nerves.
The wall of the duodenum consists of the mucous membrane, submucosal layer, muscle and serous membranes (in places covered with peritoneum). In the submucosal layer, especially in the initial part of the duodenum, there are the duodenal (Brunner) glands (similar in structure and function to the pyloric glands), as well as the plexus of arteries, veins, lymphatic capillaries and vessels and the submucosal nerve plexus (Meissner).
The muscular layer of the duodenal wall is formed by the inner circular and outer longitudinal layers. Between them is the intermuscular nerve plexus (Auerbach).
Physiology of the duodenum - see Digestion .
Research methods . The main research method is radiological, which allows to detect peptic ulcer , diverticula, stenosis, 12 duodenal tumors. Preparing the patient for an X-ray examination: a cleansing enema the night before and on the day of the study. The patient before the study should not eat, drink and medication, smoke. To study the contents of the duodenum used duodenal intubation (see).
Malformations of the duodenum are rare. They can be divided into two groups. The first includes atresia - the complete absence of the lumen of the intestine or its narrowing ( stenosis ) of varying degrees, usually localized above the large nipple of the duodenum. The section of the intestine located above the defect is greatly expanded and thinned. Vomiting "fountain" appears in the first hours of a child's life. Early comes progressive depletion . The diagnosis is simple. Pylorospasm , in which vomiting appears much later, there is no progressive exhaustion, bile is usually present in vomit. The prognosis is poor in the presence of atresia and pronounced stenosis. The child dies in the first week of life. Treatment : urgent surgery.
The second group includes the excessive development of the duodenum - megaduodenum. It is very rare and may be asymptomatic. Abundant vomiting with an admixture of bile and pancreatic juice occurs during the development of inflammatory processes ( duodenitis, periduodenitis ) in a strongly stretched intestine, the appearance of an ulcer, a diverticulum. Treatment is prompt.