The stomach lies just below the diaphragm in the upper part of the abdominal cavity primarily to the left of the midline under a portion of the liver. The main divisions of the stomach are the following: Show
CardiaThe cardia is the portion of the stomach surrounding the cardioesophageal junction, or cardiac orifice (the opening of the esophagus into the stomach). Tumors of the cardioesophageal junction are usually coded to the stomach. FundusThe fundus is the enlarged portion to the left and above the cardiac orifice. BodyThe body, or corpus, is the central part of the stomach. Pyloric antrumThe pyloric antrum is the lower or distal portion above the duodenum. The opening between the stomach and the small intestine is the pylorus, and the very powerful sphincter, which regulates the passage of chyme into the duodenum, is called the pyloric sphincter. The stomach is suspended from the abdominal wall by the lesser omentum. The greater omentum attaches the stomach to the transverse colon, spleen and diaphragm. The common mesentery suspends the small intestine. The parietal peritoneum lies over the duodenum and other structures, such as the abdominal aorta. Because they lie behind the peritoneum, they are called retroperitoneal structures. The figure below shows the anatomy of the stomach. 
The pylorus ( or ), or pyloric part, connects the stomach to the duodenum. The pylorus is considered as having two parts, the pyloric antrum (opening to the body of the stomach) and the pyloric canal (opening to the duodenum). The pyloric canal ends as the pyloric orifice, which marks the junction between the stomach and the duodenum. The orifice is surrounded by a sphincter, a band of muscle, called the pyloric sphincter. The word pylorus comes from Greek πυλωρός, via Latin. The word pylorus in Greek means "gatekeeper", related to "gate" (Greek: pyle) and is thus linguistically related to the word "pylon".[1] Structure[edit]The pylorus is the furthest part of the stomach that connects to the duodenum. It is divided into two parts, the antrum, which connects to the body of the stomach, and the pyloric canal, which connects to the duodenum.[2] Antrum[edit]The pyloric antrum is the initial portion of the pylorus. It is near the bottom of the stomach, proximal to the pyloric sphincter, which separates the stomach and the duodenum. It may temporarily become partially or completely shut off from the remainder of the stomach during digestion by peristaltic contraction of the prepyloric sphincter; it is demarcated, sometimes, from the pyloric canal by a slight groove. Canal[edit]The canal (Latin: canalis pyloricus) is the opening between the stomach and the duodenum.[3] The wall thickness of the pyloric canal is up to 3 millimeters (mm) in infants younger than 30 days,[4] and up to 8 mm in adults.[5] Sphincter[edit]The pyloric sphincter, or valve, is a strong ring of smooth muscle at the end of the pyloric canal which lets food pass from the stomach to the duodenum. It controls the outflow of gastric contents into the duodenum.[6] It receives sympathetic innervation from the celiac ganglion. Histology[edit]Microscopic cross-section of the pylorus Under microscopy, the pylorus contains numerous glands, including gastric pits, which constitute about half the depth of the pyloric mucosa. They consist of two or three short closed tubes opening into a common duct or mouth. These tubes are wavy, and are about one-half the length of the duct. The duct is lined by columnar cells, continuous with the epithelium lining the surface of the mucous membrane of the stomach, the tubes by shorter and more cubical cell which are finely granular. The glands contain mucus cells and G cells that secrete gastrin.[7] The pylorus also contains scattered parietal cells and neuroendocrine cells. These endocrine cells including D cells, which release somatostatin,[8] responsible for shutting off acid secretion. (There is a second hormone-sensitive population near the fundus.) Unstriated muscles, which are entirely involuntary, are located at the pylorus. Function[edit]The pylorus is one component of the gastrointestinal system. Food from the stomach, as chyme, passes through the pylorus to the duodenum. The pylorus, through the pyloric sphincter, regulates entry of food from the stomach into the duodenum. Clinical significance[edit]In such conditions as stomach cancer, tumours may partly block the pyloric canal. A special tube can be implanted surgically to connect the stomach to the duodenum so as to facilitate the passage of food from one to the other. The surgery to place this tube is called a gastroduodenostomy. Stenosis[edit]Pyloric stenosis refers to a pylorus that is narrow. This is due to congenital hypertrophy of the pyloric sphincter. The lumen of the pylorus is narrower, and less food is able to pass through. This problem is often detected in the early weeks of life. When it is present, a newborn baby may projectile vomit after eating, but despite vomiting remain hungry. Pyloric stenosis may be managed by the insertion of a stent, or through surgical cutting of the pyloric sphincter, a pyloromyotomy.[9] Other[edit]
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What is the valve between the stomach and the duodenum?The part of the stomach that connects to the duodenum (first part of the small intestine). The pylorus is a valve that opens and closes during digestion. This allows partly digested food and other stomach contents to pass from the stomach to the small intestine.
What causes pyloric sphincter dysfunction?The outlet of the stomach (the pylorus and duodenum) may be obstructed by an ulcer or tumor, or by something large and indigestible that was swallowed. The pyloric sphincter at the exit of the stomach may not open enough or at the right times to allow food to pass through.
What is a sphincter valve?Sphincter. Description. It is a membranous structure found in hollow organs that allows the flow of fluids in one direction. It is a circular muscle that contracts and relaxes to allow bodily fluids to pass through the passages.
What sphincter is in the duodenum?First described by Ruggero Oddi in 1887, the sphincter of Oddi (SO) is a smooth muscle sphincter located in the second portion of the duodenum. [1] It regulates the flow of hepatic and pancreatic substances into the small intestines.
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Sphincter valve between the stomach and duodenum
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