Pharynx: The hollow tube that is about 5 inches long and starts behind the nose and ends at the top of the trachea (windpipe) and esophagus. The pharynx serves as a vestibule or entryway for the trachea and esophagus. SLIDESHOW Heart Disease: Causes of a Heart Attack See Slideshow From Healthy Resources 10 Rheumatoid Arthritis SymptomsWhat Is Exocrine Pancreatic Insufficiency?Truth About Vitamin B12 Featured Centers Good and Bad Foods for PsoriasisVideo: Getting Personal on Life With MS Health Solutions From Our Sponsors Shot-Free MS Treatment Your Child and COVID-19