Why Your Ear Unblocks With a Swallow

The Eustachian tube is a narrow channel, about 35 mm long in adults, that connects the back of your nasopharynx to your middle ear. It is normally closed. Its only job is to equalize air pressure on both sides of your eardrum, and it does this by briefly popping open whenever a muscle called the tensor veli palatini — one of the soft-palate muscles — contracts. Swallowing, yawning, and chewing all activate it. That's why airline attendants suggest gum.

Antonio Valsalva described the tube in 1704 and named it after Bartolomeo Eustachi, the 16th-century Italian anatomist who drew it first. Valsalva also described the maneuver that bears his name: closing your mouth and nostrils and gently blowing, to force the tube open with pressure from inside. Pilots, divers, and anyone who has flown with a head cold knows the trick.

In children, the tube is short (about 18 mm), almost horizontal, and prone to blockage. Add adenoid tissue swollen from a cold, and drainage from the middle ear stops. Bacteria that live quietly in the nasopharynx — Streptococcus pneumoniae, Haemophilus influenzae — ride the fluid into a warm, closed chamber and multiply. That's an ear infection. It is the most common reason children are prescribed antibiotics. By age six, tubes have tilted toward the adult angle and infections taper off on their own.

The ear tubes surgeons insert in chronic cases are called tympanostomy tubes, or grommets: tiny PTFE cylinders threaded through a slit in the eardrum to vent the middle ear directly until the kid's anatomy catches up. They fall out on their own within six to eighteen months as the eardrum heals around them. Roughly 1 in 15 American children gets a set by age three.