Formation of Pylorus
Diagram to show formation of pylorus. Labels: P, peritoneum; L, longitudinal layer of muscular fibers; C, circular layer; M, mucous membrane; V, villi. It will be seen that the pyloric narrowing is due practically entirely to a gradual thickening of the circular muscular fibers, which stops abruptly at the pyloric orifice.
GalleriesHuman Digestive System
Cunningham, D.J. Textbook of Anatomy (New York, NY: William Wood and Co., 1903)