[Vascularization of the pharyngo-esophageal transition zone]

The arterial blood supply and the venous drainage of the area around the pharyngo-oesophageal sphincter are still virtually unknown. We performed vascular injections with a gelatin-india ink solution on autopsy specimens. After fixation the specimens were dissected under a stereomicroscope. From our anatomic studies we conclude that the inferior thyroid artery gives rise to a special branch, the "laryngopharyngeal artery", that supplies the pharyngo-oesophageal sphincter through numerous transversal branches. This density can be explained by the oxidative metabolism of the cricopharyngeal muscle. This structural adaptation is necessary for the maintainance of a continuous tone within the pharyngo-oesophageal sphincter. The pharyngo-oesophageal venous plexus in the laryngopharynx and cervical oesophagus provides rigidity to the surrounding corium and so ensures the integrity of the corium during sphincter relaxation.