The pylorus is the junction between the stomach and the duodenum (Latin pylores = gatekeeper).
It contains a sphincter muscle, the pyloric
sphincter, within a fold of mucous
membrane which closes off the junction during digestion of food in the stomach. The pyloric sphincter surrounds the pyloric
orifice, the opening of the stomach into the duodenum. At the location
of the sphincter, the pylorus is marked by a slight annular groove on its
surface called the pyloric constriction. The part of the
stomach that immediately precedes the pylorus is a nearly cylindrical tube
called the pyloric canal. The pyloric antrum is a variable dilation at the lower border of the stomach, immediately to
the left of the pyloric canal and continuous with the body of the stomach.
|Stomach, upper aspect