The pylorus, a cone-shaped structure, is the region of the stomach that connects to the duodenum (the beginning of the small intestines). It is divided into two parts: the pyloric antrum, which connects to the body of the stomach. and the pyloric canal, which connects to the duodenum. To keep food from going back into the stomach once it has moved into the small intestine is the primary function of the pylorus. It also works to limit the amount of undigested food that is able to move into the intestinal tract. 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 receives sympathetic innervation from the celiac ganglion. This is a mass of nerve tissue located in the upper abdomen. One medical condition associated with the pylorus is pyloric stenosis. One method of relieving this partial or complete obstruction is the surgical placement of a pyloric stent. This stent is synthetic tube which maintains patency between the stomach and proximal duodenum. 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. This tube is called a gastroduodenostomy.