[Clinical anatomy of the pyloric region].
The pylorus is not an isolated sphincter but is rather a concentration of muscle bundles derived from the antral muscles and interwoven with the aboral sphincter complex of the stomach. The pyloric canal can be regarded as a narrow gastric segment of merely minor dilatability. In terms of muscular architecture, the prepyloric antrum, pyloric region, and duodenal bulb are the components of the aboral sphincter mechanism of the stomach (motor unit).