hypopharynx
Meaning of hypopharynx: The last stretch of throat, where the paths of air and food finally part company and where cancer is often found late.
Definition of hypopharynx
The hypopharynx is the lowest part of the throat. It runs from about the level of the top of the voice box down to the point where the throat becomes the esophagus. Food and drink pass through it on the way to the stomach while air is diverted forward into the windpipe. It wraps around the voice box on three sides.
What are its parts?
| Subsite | Where it lies |
|---|---|
| Pyriform sinus | Paired gutters running down each side of the voice box, and the commonest site of cancer here |
| Postcricoid area | The front wall, behind the ring of cartilage at the base of the voice box |
| Posterior pharyngeal wall | The back wall, lying against the spine |
What does it do?
It solves a design problem: one throat carries both air and food. During a swallow the voice box lifts and moves forward, a flap called the epiglottis folds back over the airway, the vocal cords close and breathing pauses. The mouthful is squeezed down the two side gutters, past the sealed airway, and through a muscular valve at the bottom that opens only for the swallow. When that sequence is disrupted, by a stroke or by nerve damage, material enters the airway instead, which is the mechanism behind aspiration.
Why is cancer here found late?
The space is roomy, so a tumor can grow substantially before it obstructs anything. Early symptoms are vague and easily attributed to something else: a persistent sore throat, a sensation of something caught, and pain felt in the ear on the same side, which is sensation referred along a shared nerve rather than ear disease. Hoarseness appears only once the tumor reaches the voice box, and difficulty swallowing with weight loss comes later still. A large share of cases are noticed first as a lump in the neck, meaning lymph nodes are already involved. Smoking and alcohol together are the dominant risks, and long-standing iron deficiency with a web in the upper esophagus has a recognized association with postcricoid tumors. Because the region sits at a crossroads, treatment of hypopharyngeal cancer has to weigh removing the disease against preserving speech and swallowing.
How does it relate to the rest of the throat?
The throat is described in three levels. The nasopharynx sits behind the nose, the oropharynx behind the mouth and contains the tonsils and the base of the tongue, and the hypopharynx lies below both. Each level has its own pattern of disease, and the human papillomavirus link that has reshaped tonsil cancer does not extend to this lower region.
Also known as
Used in a sentence
Endoscopy showed a lesion arising from the left pyriform sinus of the hypopharynx.
Good to know
Persistent one-sided ear pain with a normal ear examination can be sensation referred from the hypopharynx along a shared nerve, a pattern easily mistaken for disease of the ear itself.
Word origin
Where “hypopharynx” comes from
From the Greek hypo, meaning under, and pharynx, meaning throat.