1 — Sphincter of bile duct; 2 — Sphincter of ampulla; 3 — Hepatopancreatic ampulla; Biliaropancreatic ampulla; 4 — Duodenum, anterior wall; 5 — Sphincter of pancreatic duct; 6 — Circular layer; Short pitch helicoidal layer; 7 — Longitudinal layer; Long pitch helicoidal layer; 8 = 6 + 7 — Duodenum, muscular layer, muscular coat; 9 — Longitudinal slips of duodenal muscle on common bile duct; 10 — Bile duct;
11 — Pancreatic duct
