Happy hump day, subscribers! I’ve been trying to keep you swimming in content, but I know this newsletter has been a little dry. My freelance business has been picking up while my health has stayed meh at best, so I haven’t had a ton of time to muse on bloggy things. I do hope to start writing at a more regular clip soon, and perhaps even come up with some premium offerings to thank those of you who have generously opted for paid accounts (I so appreciate it!)
For today, I wanted to share my latest PopSci package for your amusement. It’s about butts. All sorts. Wombat butts (did you know they literally use them to armor the entrances of their burrows?) and human butts and smart toilets and ancient latrines and everything in between.
The best part of reporting this package—which, to be clear, was a juicy delight from start to finish—was my conversation with the cheekily-named REAR Lab at Georgia Tech. Here are a few highlights from the piece:
As Sharon Sonenblum, a principal research scientist in the School of Mechanical Engineering at Georgia Tech, puts it: “What could be better than studying butts?” The Rehabilitation Engineering and Applied Research Lab that she’s part of is perhaps more aptly referred to by its acronym: REAR.
The big headline, says Stephen Sprigle, a Georgia Tech professor with appointments in Bioengineering, Industrial Design and the George W. Woodruff School of Mechanical Engineering, is that “we’re big bags of water.” “What the skeleton does in that big bag of goo is totally fascinating,” he says.
“I’ve seen scans of butts that look like this, and when I do, I think—wow, that’s a high-risk butt,” Sonenblum explains. It comes down to the quality of the tissue, she adds. “If you touch a lot of butts, you’ll find that the tissue changes for people who are at risk [of pressure injuries]. It feels different.”
Here are some other tidbits that ended up on the cutting room floor, in no particular order:
Sonenblum actually set out to study how the muscles of the butt influence the biomechanics of sitting. But she’s found that we don’t really sit on muscle at all. No matter how shapely and pert your Gluteus Maximus seems while you’re standing up, it flees the scene as soon as you sit. We’re mostly balancing on adipose and tendons.
The Rear Lab does a lot of work on improving wheelchair cushion design and testing. One of their more surprising findings was that, for some wheelchair users, different cushion designs don’t seem to make a difference in seat comfort—at least based on MRI images of the butt’s deformation when pressed into the chair. But when users rated their preferences, they identified major differences in how the cushions felt. That leads me to an unfortunate but glorious descriptor for atrophied butt tissue that my sources kept coming back to:
“It comes back to that bag of goo,” Sonenblum said. “If your butt is basically cottage cheese, because you don't have any good tissue left, it’s not very resilient. You sit down and it deforms right away. That's going to happen no matter what you sit on. But that doesn't necessarily mean all products are equal for you. There's still going to be additional stress when you move.”
Sonenblum and Sprigle are also working on mitigating the risk of bed sores in supine patients, and the big bag of goo analogy comes in handy here, too.
“This idea of this big bag of goo and how the skeleton moves in it becomes really important in terms of how people lie in bed and what we do for prevention there,” Sonenblum said. Vertical prophylactic dressings—essentially giant Band Aids that go over your lower back—are the standard of care for bed sore prevention. They work quite well, Sonenblum says, and there’s plenty of evidence to show it. But folks aren’t quite clear on why. “A lot of people talk about the cushioning that they provide, but our images suggest something else is going on. If anyone argues with me, they should grab a Band Aid and try to use it as a pillow for a couple of nights. But when you think about the skeleton moving in there, in this big bag of goo, the bandage has the opportunity to hold the tissue and to keep the tissue together and to change what's going on and where the skeleton can move relative to the tissue that's contained by this dressing. And that's something you can only see in the images. If you just sort of make assumptions and do modeling, you might not make the correct assumptions.”
And you know what happens when you assume!
I honestly wish someone had told me back in college that mechanical engineers can study butts for a living. I think I would have set off on a very different career path.
Rachel’s Recs
Save the date for: A Weirdest Thing live show in NYC on August 24!
Come hang out with me at: This awesome speed friending event I’m helping to organize on May 25!
Buy: Some socks I made