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11 Striking Facts About the Jugular

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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.

Jugular veins are popular in horror flicks for their gushing at the mouths of vampires, werewolves, and knife-wielding assassins. While that's unlikely to happen to most of us, this crucial vein does give up copious blood. Jugular veins are big—much larger than the veins you typically offer to your doctor for a blood test and those you find spidering off the side of your legs. Jugular veins are also key players in the circulation and drainage systems to the brain, face, and neck. To learn more, Mental Floss spoke with William W. Ashley, a cerebral-vascular neurosurgeon at Sandra and Malcolm Berman Brain & Spine Institute at LifeBridge Health Hospital, in Baltimore, Maryland. Here are 11 things you might not have known about this crucial body part.

1. IT'S A REAL BRAIN DRAIN.

"The jugular vein is an important body part because it drains deoxygenated blood from the head and the neck," Ashley tells Mental Floss. "Most important is to drain the brain. If you block the jugular veins, the pressure in the brain goes up."

2. YOU ACTUALLY HAVE FOUR JUGULAR VEINS.

There's an internal and an external jugular vein on each side of the neck. The internal jugular vein (really a pair of veins) largely drains the cerebral veins—those coming from the brain—while the external jugular vein (also a pair) drains those structures more on the surface of the head, such as the scalp, sinuses, and other portions of the face. The left vein is usually smaller than the one on the right, but both possess valves that help transport blood. At two points in the vein it looks wider, and these parts are called the superior bulb and the inferior bulb.

3. THESE ARE THE VEINS THAT STAND OUT ON EITHER SIDE OF YOUR NECK.

Your jugular veins run alongside the thyroid gland down to just above your collarbone, and close to your trachea, or windpipe. When you're picking up a heavy box, or clenching your jaw, your jugular veins might bulge slightly. "They respond to changes in pressure, so you can see them get big and small," Ashley says.

4. SOME PEOPLE HAVE MORE THAN THEIR SHARE OF THESE VEINS …

According to the Indian Journal of Plastic Surgery, during a surgery to treat a 65-year-old woman's cancer of the tongue, surgeons discovered a surprise: She had two right internal jugular veins, "a rare congenital abnormality," the authors write. While unusual, it didn't appear to cause any other health problems.

5. … WHILE OTHERS MAKE DO WITH FEWER.

Ashley had a patient with the opposite issue: "I've seen an absence of one [right vein] where everything drained on the left side. We found it incidentally. If she injured her one jugular vein, she'd be in bad shape. We were doing an angiogram to see if she had a brain aneurism." Her dearth of jugulars hadn't caused any health problems, however, he said, because "the body had adopted a different pattern [of drainage]."

6. A BULGING JUGULAR VEIN CAN BE A CAUSE FOR ALARM.

A bulging or "distended" jugular vein can be a sign of emergency. Unless you're The Hulk, that distended vein is a sign that the jugular is carrying more blood than the heart has the ability to pump back out. The conditions that can cause this include tension pneumothorax—where air has leaked from the lungs into the chest cavity and can't get back out without being released by a needle—or cardiac tamponade, a condition where fluid leaks from the heart into the pericardium, the sac that surrounds the heart. In this case, pericardiocentesis is required—drawing the fluid out through a needle. Lastly, constrictive pericarditis, an infection of the pericardium, can also cause this condition, which may require surgery and antibiotics to treat.

7. IN RARE CASES, IVF IS LINKED TO DANGEROUS INTERNAL JUGULAR VEIN BLOOD CLOTS.

A blood clot in the internal jugular veins (IJV), known as a thrombosis, is a very serious condition that can prove fatal if not caught and treated quickly. Clots in the IJV are rare compared to those that occur in legs and lungs, but they can happen. Most commonly they are the result of an infection or a tumor. In a very small number of cases, in vitro fertilization (IVF) treatments, in which a woman receives hormones and drugs to stimulate ovulation to increase chances of pregnancy, can cause a thrombosis of the IJV. This seems to be related to ovarian hyper stimulation syndrome (which can occur in an IVF cycle), where swelling and inflammation of the ovaries also causes blood leaving the ovaries to become hypercoagulated, or extra thick. This thickened blood can then form a clot in the IJV. Any thrombosis is treated with anticoagulation medicines, and if infection is present, antibiotics.

8. THESE VEINS DON'T DO WELL UNDER PRESSURE …

"One interesting thing about them is that they can cause a variety of brain problems, such as elevated pressure in the brain," says Ashley. One is a condition known as Eagle syndrome, which he calls "pretty cool" (as only a cerebral-vascular neurosurgeon could). In this syndrome, "a congenital bony prominence at the base of skull pushes on the jugular vein and causes the brain to swell up and become engorged with blood," Ashley describes. As the pressure builds in the brain, it has to be surgically released or it will cause serious damage. "We can do that by putting in a shunt [in the brain] to drain off fluid," he says. Occasionally, doctors can also surgically remove the piece of the bone that's causing the problem.

9. … OR WITH TRAUMA, WHICH IS THE MOST COMMON CAUSE OF CONSTRICTION.

Other than congenital issues—those you're born with—the most common causes of constriction in the jugular veins are from traumas, such as car accidents and other traumatic brain or neck injuries. "Blood clots and trauma can constrict the jugular vein," Ashley says, as can "congenital narrowing of the vein."

10. WE CAN NOW TREAT JUGULAR-DERIVED BRAIN PRESSURE BETTER.

In the past five to 10 years, surgeons have begun to use stents, metal tubes inserted directly into the vein, to open it up. "A shunt is a tube that goes into the brain that helps drain off spinal pressure. The stent goes into the vein, that's a little more elegant a solution," Ashley says.

11. AS EVERY HORROR MOVIE SUGGESTS, BE CAREFUL WITH SHARP OBJECTS AROUND YOUR JUGULAR.

If your jugular is punctured, Ashley warns, "you can rapidly lose blood." A needle is less likely to cause problems than a knife, but blood is likely to flow out of your jugular "more rapidly than out of a vein in wrist or arm," making a puncture a serious problem.

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The American Museum of Natural History
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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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The Body
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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