Ugh, What Are Sinuses Even For? An Inquiry | Vol. 3 / No. 47.2

Image: NIAID, CC BY 2.0

Maybe it’s because the right side of my face feels like somebody snuck a slowly-expanding golfball into my skull while I slept last night, but I’ve suddenly found myself remarkably curious about what exactly the sinuses in your face are for.

Wikipedia says there are a number of “functions” of the paranasal sinuses, these obnoxious holes in my head whose passages clog and create pressure differentials with the outside world. Among the reasons are a number of things I don’t know if I buy. They apparently “increase the resonance of the voice,” “humidify and heat of inhaled air because of slow air turnover in this region,” and “decrease the relative weight of the front of the skull.

As for use number one, I don’t know about you, but I don’t have the most pleasant of voices. Barry White I am not. My laugh sounds like this, though, so maybe I’m just not using my sinuses right or something. Advice?

Reason number two sounds like an added effect rather than a function. Oh yeah, we’ve got these holes in our skulls full of mucus and they, you know, uh, moisturize the air. If we breathe it through our noses. Which we can’t do if our sinuses are full of mucus (checkmate, atheists!). Moving on.

Function number three sounds pretty sketchy as well, if I’m being honest. I mean, if I had to choose between a heavier skull and one that feels like it’s harboring a malicious balloon colony on a surprisingly regular basis, I’d probably take the heavy head.

But this brings us to what is probably the very real case: all sarcasm aside, they’re probably leftovers that evolution didn’t see any reason to fix, because cumulatively they produced a slight advantage and it would’ve been a cost to get rid of them. Having slightly more humid air in your lungs isn’t likely to make or break your ability to outbreed the competition, nor is, I suspect, having a slightly lighter head (though they seem to make it safer to take a punch, it turns out, and might also have an immune function).

But the paranasal sinuses predate humans by, well, a long ways anyhow, and probably served a useful function in terms of olfaction in the past. Now having a good sense of smell really is a make-or-break thing for animals on Earth, and even though humans’ sense of smell isn’t great compared to much of the animal kingdom, we’re not who paranasal sinuses were originally for (it’s not about you, intelligent designers. Come to think of it, it’s never been about you). And a lighter skull is probably more useful (and less resource intensive) when your skull is five feet long.

So long story short, sinuses probably developed for things that came before us, and we didn’t jettison the design because apparently carving out a spot to let evil literally live in your face is preferable to the alternative, which seems to be dryer breathing air and a face that can’t get hit without sustaining damage. Congratulations, people who fist-fight in deserts, sinuses are for you.

Today’s post has been brought to you by colds.

Colds: hijacking your mucus production centers to reproduce their evil selves since forever.


Thanks for reading! Except for the very *very* occasional tip (we take Venmo now!), I only get paid in my own (and your) enthusiasm, so please like This Week In Tomorrow on Facebook, follow me on Twitter @TWITomorrow, and tell your friends about the site!

If you like our posts and want to support our site, please share it with others, on Facebook, Twitter, Reddit — anywhere you think people might want to read what we’ve written. Thanks so much for reading, and have a great week.


Richard Ford Burley is a human, writer, and doctoral candidate at Boston College, as well as an editor at Ledger, the first academic journal devoted to Bitcoin and other cryptocurrencies. In his spare time he writes about science, skepticism, feminism, and futurism here at This Week In Tomorrow.