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6 Quick Facts About the Buttocks

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The human body is an amazing thing. For each one of us, it's the most intimate object we know. And yet most of us don't know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

You can thank your buttocks for a number of physical actions you take every day, from moving your hip and thigh during walking or running, to rising from a sitting position, climbing, and even just standing upright. While lack of exercise can make these muscles soft, in general they're some of the hardest working muscles in your body. To learn more, Mental Floss spoke with Clifford Stark, medical director of Sports Medicine at Chelsea in New York City, and Vivian Eisenstadt, an orthopedic and spine specialist in physical therapy in Los Angeles. Here are six quick facts we picked up about the glutes.

1. WHEN IT COMES TO THE BOOTY, BIGGER MIGHT BE BETTER.

Your glutes are your body's largest and most powerful muscle group, Stark tells Mental Floss. Your powerful buttocks are actually comprised of three gluteal muscles: the gluteus maximus, gluteus medius, and gluteus minimus, often shorthanded to "the glutes."

"They are extremely important in preventing all sorts of injuries," Stark adds. Many injuries, from hips to knee, stem from weak gluteal muscles. It's important to keep your glutes strong—but not tight.

2. IF YOU'RE NOT BORN WITH IT, YOU CAN PAY FOR IT.

In 2016, 4251 people in the U.S. got a butt lift, and another 2999 got butt implants, according to the American Society of Plastic Surgeons' 2016 Report [PDF]. These numbers make sense, because according to the professional organization, butt implants were the fastest growing type of plastic surgery in 2015. Yet while butt surgery may be increasingly popular, it still hasn't cracked the top 5 of cosmetic surgical procedures (breast augmentation, liposuction, nose reshaping, eyelid surgery, and facelift, in that order).

3. WHY DO WE CALL A BARE BUTT A "FULL MOON"?

In the Ming dynasty in China, bare buttocks were seen as quite erotic and they were often compared to a full moon, perhaps because of their pert roundness.

4. VICTORIANS WERE REALLY INTO EROTIC SPANKING.

While spanking has been proven bad for kids, it may be good for your sex life. Victorians were particularly obsessed with "erotic spanking." According to Deborah Lutz, author of Pleasure Bound: Victorian Sex Rebels and the New Eroticism, "something like 50 percent of the pornography of the time was flagellation pornography," she told Salon. One prevailing theory suggests that the practice has its roots in the upper-class men who as children had attended private schools, where a common punishment was to be whipped in front of their classmates with birch switches. "Any schoolboys who wanted to could come and watch. For many of these boys, of course, it was traumatic, but for other boys it's an erotic experience. It developed into this masochistic eroticism," Lutz said.

5. BACK PAIN MAY ORIGINATE IN YOUR BUTTOCKS.

"A little-known fact is that strengthening your buttocks helps decrease back pain," Eisenstadt tells Mental Floss. "While physical and occupational therapists know this, many people are not aware and increase risk of injury by neglecting this important muscle." In her practice, when people come in complaining of back pain, she checks out their butts first.

6. A SMALL NUMBER OF PEOPLE HAVE THIS UNUSUAL POSITIONING OF THE SCIATIC NERVE.

"Sciatica is a laymen's term for pain down the leg," says Stark. The sciatic nerve typically lies right on top of the piriformis muscle, a small muscle that lives deep in the buttock, behind the gluteus maximus. For a certain percentage of the population, however, he says, the sciatic nerve sometimes pierces right through the muscle. Those people are especially prone to sciatic pain, he says: "All it takes is a spasm to cut off that nerve."

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10 Surprising Ways Senses Shape Perception
The American Museum of Natural History
The American Museum of Natural History

Every bit of information we know about the world we gathered with one of our five senses. But even with perfect pitch or 20/20 vision, our perceptions don’t always reflect an accurate picture of our surroundings. Our brain is constantly filling in gaps and taking shortcuts, which can result in some pretty wild illusions.

That’s the subject of “Our Senses: An Immersive Experience,” a new exhibition at the American Museum of Natural History in New York City. Mental Floss recently took a tour of the sensory funhouse to learn more about how the brain and the senses interact.

1. LIGHTING REVEALS HIDDEN IMAGES.

Woman and child looking at pictures on a wall

Under normal lighting, the walls of the first room of “Our Senses” look like abstract art. But when the lights change color, hidden illustrations are revealed. The three lights—blue, red, and green—used in the room activate the three cone cells in our eyes, and each color highlights a different set of animal illustrations, giving the viewers the impression of switching between three separate rooms while standing still.

2. CERTAIN SOUNDS TAKE PRIORITY ...

We can “hear” many different sounds at once, but we can only listen to a couple at a time. The AMNH exhibit demonstrates this with an audio collage of competing recordings. Our ears automatically pick out noises we’re conditioned to react to, like an ambulance siren or a baby’s cry. Other sounds, like individual voices and musical instruments, require more effort to detect.

3. ... AS DO CERTAIN IMAGES.

When looking at a painting, most people’s eyes are drawn to the same spots. The first things we look for in an image are human faces. So after staring at an artwork for five seconds, you may be able to say how many people are in it and what they look like, but would likely come up short when asked to list the inanimate object in the scene.

4. PAST IMAGES AFFECT PRESENT PERCEPTION.

Our senses often are more suggestible than we would like. Check out the video above. After seeing the first sequence of animal drawings, do you see a rat or a man’s face in the last image? The answer is likely a rat. Now watch the next round—after being shown pictures of faces, you might see a man’s face instead even though the final image hasn’t changed.

5. COLOR INFLUENCES TASTE ...

Every cooking show you’ve watched is right—presentation really is important. One look at something can dictate your expectations for how it should taste. Researchers have found that we perceive red food and drinks to taste sweeter and green food and drinks to taste less sweet regardless of chemical composition. Even the color of the cup we drink from can influence our perception of taste.

6. ... AND SO DOES SOUND

Sight isn’t the only sense that plays a part in how we taste. According to one study, listening to crunching noises while snacking on chips makes them taste fresher. Remember that trick before tossing out a bag of stale junk food.

7. BEING HYPER-FOCUSED HAS DRAWBACKS.

Have you ever been so focused on something that the world around you seemed to disappear? If you can’t recall the feeling, watch the video above. The instructions say to keep track of every time a ball is passed. If you’re totally absorbed, you may not notice anything peculiar, but watch it a second time without paying attention to anything in particular and you’ll see a person in a gorilla suit walk into the middle of the screen. The phenomenon that allows us to tune out big details like this is called selective attention. If you devote all your mental energy to one task, your brain puts up blinders that block out irrelevant information without you realizing it.

8. THINGS GET WEIRD WHEN SENSES CONTRADICT EACH OTHER.

Girl standing in optical illusion room.

The most mind-bending room in the "Our Senses" exhibit is practically empty. The illusion comes from the black grid pattern painted onto the white wall in such a way that straight planes appear to curve. The shapes tell our eyes we’re walking on uneven ground while our inner ear tells us the floor is stable. It’s like getting seasick in reverse: This conflicting sensory information can make us feel dizzy and even nauseous.

9. WE SEE SHADOWS THAT AREN’T THERE.

If our brains didn’t know how to adjust for lighting, we’d see every shadow as part of the object it falls on. But we can recognize that the half of a street that’s covered in shade isn’t actually darker in color than the half that sits in the sun. It’s a pretty useful adaptation—except when it’s hijacked for optical illusions. Look at the image above: The squares marked A and B are actually the same shade of gray. Because the pillar appears to cast a shadow over square B, our brain assumes it’s really lighter in color than what we’re shown.

10. WE SEE FACES EVERYWHERE.

The human brain is really good at recognizing human faces—so good it can make us see things that aren’t there. This is apparent in the Einstein hollow head illusion. When looking at the mold of Albert Einstein’s face straight on, the features appear to pop out rather than sink in. Our brain knows we’re looking at something similar to a human face, and it knows what human faces are shaped like, so it automatically corrects the image that it’s given.

All images courtesy of the American Museum of Natural History unless otherwise noted.

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8 Little Known Facts About the Temple
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The human body is an amazing thing. For each one of us, it’s the most intimate object we know. And yet most of us don’t know enough about it: its features, functions, quirks, and mysteries. Our series The Body explores human anatomy, part by part. Think of it as a mini digital encyclopedia with a dose of wow.

 

At the edges of the eyebrows, you’ll find the temple, the flat, tender side of the head where you often press your fingers to relieve a headache. In movies, one karate chop to this area can allegedly kill a person, but is this really true? What lies beneath that smooth surface of skin that’s so delicate? To learn more, Mental Floss spoke to Dr. Abbas Anwar, an otolaryngologist and head and neck surgeon at Southern California Head and Neck Medical Group in Santa Monica.

1. THE TEMPLE IS A JUNCTURE.

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It's technically where four skull bones—the frontal, parietal, temporal, and sphenoid—meet in the skull. This vulnerable juncture is called the pterion, which means "wing" in Greek but sounds like a kind of dinosaur.

2. IT REVEALS A DISTANT LINK TO REPTILES.

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The temporal bone itself is made up of five smaller parts, which fuse together before birth. One of these pieces, called the tympanic part, may be evolutionarily linked to the angular bone in the lower jaws of reptiles.

3. IT'S THE THINNEST PART OF THE SKULL …

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While these skull bones are "relatively strong," though thin, Anwar tells Mental Floss, the point at which they meet is the weakest point because there's no solid bone beneath them. "As such, this area is at risk with direct horizontal blows."

4. … WHICH IS WHY MAORI WARRIORS CRAFTED A SPECIAL WEAPON TO CRUSH IT.

maori stone club
Australian Museum, Wikimedia Commons // CC BY-SA 3.0

When Maori warriors of the first nations tribes of New Zealand and Australia went into battle, one weapon they took with them was the patu onewa, a flat, heavy club carved from stones such as basalt, and sometimes jade, for the specific purpose of delivering a fatal, crushing blow to the temple.

5. THE TEMPLE COVERS A MAJOR ARTERY.

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Running below these bones is a large artery known as the middle meningeal artery. It supplies blood to the outer covering of the brain, the meninges. "If hit hard enough, one of the four bones at this point can fracture inward and lacerate the middle meningeal artery," Anwar explains. This can cause an epidural hematoma, essentially "a collection of blood that builds up around the brain and compresses it."

Severe bleeding can cause "catastrophic consequences" if not recognized and treated promptly, including brain herniation (bulging brain tissue), hemiparesis (weakness of one side of the body), and death.

6. IS YOUR TEMPLE A SACRED SPACE?

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Etymologists don't entirely agree on the meaning of the word temple, which has multiple origins. It may derive from the Latin word for time, tempus, according to a Dartmouth Medical School anatomy course: "The connection may be that with the passage of time, grey hairs appear here early on. Or it may relate to the pulsations of the underlying superficial temporal artery, marking the time we have left here."

It could also possibly hail from the Greek word temenos, meaning "place cut off," which would explain the idea of a temple of worship as well as that juncture of bones at the side of the head. 

In Old English, tempel meant "any place regarded as occupied by divine presence," which might be code for the brain as the residence of consciousness or God.

More likely it's related to the Greek pterion, which as you'll recall means "wing." In Greek mythology, Hermes, messenger of the gods, wore a helmet with wings, which were positioned over the temples.  

7. IT'S PRONE TO SKIN CANCER THAT'S HARD TO REMOVE.

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Surgeon Gabriel Weston writes in The Guardian that skin cancers frequently turn up in this area from over exposure to the Sun, which makes for a challenging surgical procedure. "It is often not possible simply to sew up the hole in the skin after cutting a cancer out, since doing so can easily distort the contour of the eye," he writes.

To get around the problem, Weston uses a special technique called a Wolfe graft. After cutting away the cancerous lesion, "I measure out a circle of equal size in the skin above the collar-bone (where the skin is similar) and remove it." He grafts this skin patch to the patient's temple "with tiny silk sutures." 

8. BRAIN FREEZE ISN'T IN YOUR BRAIN.

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Sometimes when you eat or drink something cold too quickly, you get brain freeze, which can feel like someone has taken knives to your temples. But the pain isn't actually in your brain at all, as brains have no pain receptors. While researchers haven't been able to determine a cause of what's technically called sphenopalatine ganglioneuralgia, or sometimes HICS ("headache attributed to ingestion or inhalation of a cold stimulus"), they theorize that the painful freeze you experience is likely caused by a quick cooling of the blood in the back of your throat at the juncture your internal carotid and anterior cerebral arteries, which can cause spasms or constrictions of the arterial branches.

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