The hypopharynx is the bottom part of the pharynx (throat). The pharynx is a hollow tube about 5 inches long that starts behind the nose, goes down the neck, and ends at the top of the trachea (windpipe) and esophagus (the tube that goes from the throat to the stomach). Air and food pass through the pharynx on the way to the trachea or the esophagus. Most hypopharyngeal cancers form in squamous cells, the thin, flat cells lining the inside of the hypopharynx. The hypopharynx has 3 different areas. Cancer may be found in 1 or more of these areas.