CLOSE
iStock
iStock

9 Interesting Facts About the Ribs

iStock
iStock

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.

Ribs are not just an incredibly tasty order on the menu at the nearest steak house: These bony spindles in your torso attach to your sternum (breast bone) to protect your lungs, heart, spleen, and most of the liver and help with giving shape to your chest cavity, which assists in breathing. Ribs are protective on the one hand, but if badly broken, your ribs can turn lethal to you, piercing your organs. Mental Floss spoke to John Martinez, MD, an urgent care provider with Dignity Health Medical Foundation in California for these nine fascinating facts about the ribs.

1. YOUR RIBS MOVE LIKE A BUCKET HANDLE.

The ribs allow chest expansion for breathing, Martinez explains. "They function similarly to the bucket handle on a bucket and swing upwards as we take a breath, allowing the thoracic cavity to expand." This increase in the thoracic cavity makes it easier to take a breath.

2. YOU HAVE THREE TYPES OF RIBS.

The human skeleton has 12 pairs of ribs. Working from the top of the torso down, ribs 1 to 7 are considered "true ribs," as they connect directly from the spine to the sternum, Martinez says. Ribs 8 to 10 are called "false ribs" because they don't connect directly, but have cartilage that attaches them to the sternum. Ribs 11 and 12 are called "floating ribs" because they only connect to the spine in back. These, he says, "are much shorter."

3. THIS MYTH ABOUT WOMEN'S RIBS PERSISTS.

In an effort to prove the Bible story of Eve as wrought from Adam's rib "true," pastors and Sunday School teachers sometimes pass along a tale that women have more ribs than men. It's not true (and that story is sexist, anyway). Gender plays no part in the number of ribs you have: It's 12 ribs for everyone. However, women's ribs are about 10 percent smaller in volume on average than men's ribs.

4. IN RARE INSTANCES, HUMANS CAN HAVE A "GORILLA RIB."

In rare cases, which have nothing to do with gender, a human might turn up sporting extra lumbar ribs, for a total of 13 pairs of ribs, much like our distant cousins, the gorillas. Thus, it's colloquially known as a "gorilla rib."

5. RIBS ARE THE REASON NEANDERTHALS DIDN'T NEED BELTS.

Neanderthals had wider, thicker rib cages than we modern slim-waisted humans, which would have made them terrible models for skinny jeans. A 2016 study in American Journal of Physical Anthropology found that the Ice-Age diet is likely responsible for the larger ribcage and wider pelvis in Neanderthals. Essentially, carbs were scarce and fat was abundant. This led to an enlarged liver, kidneys and "their corresponding morphological manifestations," the authors write. In other words, they needed more space to house bigger organs.

6. TWO VERY DIFFERENT KINDS OF ATHLETE SHARE ONE COMMON INJURY. 

"Rowers and baseball pitchers are the most common athletes to suffer from stress fractures of the ribs," Martinez says. This is caused by the serratus anterior muscle pulling on the delicate ribs. "Other athletes that may be more likely to suffer from rib stress fractures include golfers, dancers, weightlifters and volleyball players," he adds.

7. YOU CAN SNEEZE YOUR WAY TO A RIB FRACTURE.

"True" rib fractures—where the bone breaks all the way through—are usually from traumatic events such as "a hard football tackle [or] car accident," Martinez says. However, sometimes a rib fracture can occur "from sneezing or coughing due to the force of the contracting chest wall muscles on the ribs." Treatment for true rib fractures is the same as rib stress fractures.

8. WAIST TRAINING USED TO BE ALL THE RAGE … AND STILL SOMETIMES IS.

Women have historically worn corsets, undergarments that cinch the torso in, particularly at the waist, bringing ribs and organs closer together for a smaller waist and more prominent bust. Despite corsets having gone out of fashion by the 1920s, when women began to prefer the looser, more flowing garments of the Flapper era, a number of contemporary women still wear them for reasons ranging from aesthetics to performance art, spawning a practice known as tight lacing or waist training. In this movement, women actively whittle their waists down to exceptionally small circumferences.

Doctors warn that there is risk of permanent damage to squished organs, as well as such uncomfortable syndromes as acid reflux syndrome and back pain. But it doesn't stop those who love the look.

9. THE GUINNESS RECORD HOLDER FOR A TINY WAIST IS 15 INCHES.

2011 Guinness Book of World Records winner Cathie Jung got her waist down to 15 inches through tight lacing by wearing corsets 24 hours a day, and moving down to smaller and smaller sizes. Her waist now has the same circumference as a regular jar of mayonnaise.

nextArticle.image_alt|e
iStock
arrow
The Body
11 Amazing Facts About Veins
iStock
iStock

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.

Beneath your skin, and deeper within your body, run networks of veins. These thin, tube-like structures are an essential part of the circulatory system, which distributes blood and nutrients throughout the body. What Thomas E. Eidson, a phlebologist (vein disease specialist) at Atlas Vein Care in Arlington, Texas, finds most compelling about veins is "how absolutely intricate and fragile the circulatory system can seem and yet at the same time be so resilient and adaptive."

1. VEINS ARE ONE OF THREE KINDS OF BLOOD VESSELS.

Three types of blood vessels make up the human circulatory system: arteries, veins, and capillaries. All three of these vessels transport blood, oxygen, nutrients, and hormones to organs and cells. While arteries carry oxygenated blood away from the heart to the tissues of the body, veins carry oxygen-depleted blood from the tissues back to the heart, and in fact have special valves that help them to achieve this directional flow. Capillaries are tiny blood vessels that connect arteries to veins and allow nutrients in the blood to diffuse to the body's tissues.

2. A SINGLE VEIN IS COMPRISED OF THREE LAYERS.

Veins, small as they are, consist of three layers. According to Eidson, these layers are known as the tunica adventitia, tunica media, and tunica intima. The tunica adventitia is the tough outer layer of arteries and veins and is made mainly of connective tissues. The middle layer, tunica media, is all smooth muscle and elastic fibers. This layer is thinner in veins than in arteries. The innermost layer, tunica intima, comes in direct contact with blood as it flows through the vein. This structure is made up of smooth cells and has a hollow center known as the lumen.

3. OUR BODIES CONTAIN UP TO 100,000 MILES OF BLOOD VESSELS.

All the arteries, veins, and capillaries of a human child, stretched end to end, are estimated to wrap around the Earth about 2.5 times (the equivalent of about 60,000 miles). The amount of blood vessels in a human adult would circle our planet four times, equaling 100,000 miles, according to Eidson.

4. CAPILLARIES ARE SMALLER THAN THE WIDTH OF A HUMAN HAIR.

Capillaries are tiny—at their smallest, they're less than a third of the thickness of a human hair. But to really put it into perspective, consider that when red blood cells flow through capillaries, "[they] must travel through them one cell at a time in a single-file line," Eidson says.

5. PHYSICIANS HAD THE CIRCULATORY SYSTEM ALL WRONG UNTIL THE 17TH CENTURY.

"Physicians followed an incorrect model of the circulatory system proposed by Greek physician and philosopher Galen of Pergamon from about the 2nd century CE until the 1600s," Eidson says. According to a paper in the Journal of Thrombosis and Haemostasis, Galen thought there were two systems: one in which the liver, not the heart, produced blood that was distributed in the body centrifugally, and another where arteries carried air from the lungs and more blood to tissues. "Blood was not seen to circulate but rather to slowly ebb and flow," author W.C. Aird wrote. This attitude prevailed until 1628, when English physician William Harvey first correctly described the circulatory system and the function of the heart.

6. THE BODY CAN FORM NEW VESSELS WHEN ONE IS BLOCKED.

Eidson says the body can form new blood vessels if a pathway gets blocked, a process called angiogenesis or neovascularization. On the positive side, this is the process by which flesh wounds heal, drawing nutrients and oxygen from the nearest healthy capillaries to the site of those that are damaged; this isn't too hard given how numerous capillaries are in the body. On the negative side, this same process can lead to corneal neovascularization, in which new blood vessels invade the cornea from the limbus, a part of the eye where the cornea meets the sclera—the white part of the eye. The extra blood vessels can cause inflammation and scarring of the cornea, and even result in blindness.

7. ONE PHYSICIAN PERFORMED A PIONEERING EXPERIMENT ON VEINS IN THE ARM—HIS OWN.

German physician Werner Forssmann performed a cardiac catheterization on himself in 1929. In this procedure, a thin tube called a catheter is inserted into one of the large blood vessels in the arm that leads to the heart. The medical community at the time believed studying the heart was highly unorthodox, but Forssmann was determined to prove them wrong. If the procedure succeeded, Forssmann would be able to show that a catheter could assess the pressure in the organ and how well the heart is working.

He made an incision on the inside of his left elbow and threaded the thin tube into his heart—and had a technician take an X-ray to prove the penetration was a success. Then he calmly removed the catheter from his arm with no side effects. Now, "it's a procedure performed in the U.S. approximately 1 million times per year," Eidson says. Forssmann also went on to win the Nobel Prize for Medicine in 1956, shutting up his detractors.

8. STRONG VEINS ARE ESSENTIAL TO A STRONG BODY.

Veins return oxygen-depleted blood back to the heart against the force of gravity. "If veins are too weak—a condition called venous insufficiency—blood can pool in the legs and skin causing swelling, pain, discoloration, and wounds," says Albert Malvehy, a venous and lymphatic specialist and phlebology sonographer in Delray Beach, Florida. Chronic venous insufficiency is more common in people who are obese, pregnant, or who have a family history of the problem. It can also be caused by high blood pressure in the leg veins, as a result of sitting or standing for long stints; not enough exercise, smoking, or deep vein thrombosis (blood clots). Depending on the severity, treatments may range from medication to surgery.

9. VARICOSE VEINS ARE CAUSED BY DAMAGED VALVES.

When venous valves are damaged, blood can flow in the wrong direction and lead to stretched-out, bulging veins, Gregory P. Kezele, the medical director of Vein Clinics of Cleveland, tells Mental Floss. Varicose veins, which can range in color from purplish to neutral, appear twisted and gnarled, and may be raised on the skin's surface. (Don't confuse them with spider veins, which are clusters of bluish or reddish veins near the surface of the skin that resemble webs, hence the name.) Conditions like pregnancy, obesity, and genetic predisposition can cause them. Once varicose veins appear—usually on the legs—they require a medical procedure to get rid of them.

Veins are a critical part of normal circulation in the body, so varicose veins can be more than just a cosmetic issue. "They can be a sign of a deeper circulation problem," Malvehy says. "People with varicose veins, leg pain, restless legs syndrome, leg wounds, and leg swelling should be checked by a vein specialist."

One in five people have vein disease. As recently as 10 years ago, there were few treatments to offer varicose vein sufferers except for vein stripping surgery, in which problematic veins are removed. Malvehy says that over the past decade, "there has been a revolution in treatment, such that almost all vein issues can be treated in the office with no downtime."

One common treatment is sclerotherapy, in which a liquid solution is forced into the bulging vein to stop the flow of blood. The vein will eventually turn into scar tissue and fade away, though follow-up treatments might be needed.

Another treatment is thermal ablation, performed using ultrasound guidance. Kezele explains that a physician will insert a small catheter into the diseased veins, which then delivers heat; the heat will close off blood flow to the problem veins and improve circulation as blood diverts to healthy veins.

10. AN EARLY DEPICTION OF VEIN DISEASE APPEARS IN A SCULPTURE FROM 340 BCE.

According to Kezele, the first depiction of vein disease appears on a Greek tablet dating to the 4th century BCE. The carving, from the sanctuary of Amynos, shows a man clutching a giant, disembodied leg with a bulging vein. Kezele suggests on his website that "it shows the Greek official Lysimachides dedicating a fake leg suffering from a varicose vein to Amynos," an Athenian hero revered as a healer.

11. VEINS MIGHT "POP OUT" WHEN YOU EXERCISE.

There are lots of theories on why athletes often have big, bodaciously bulging veins visible on their arms or legs after they work out. The ropy look is completely normal and temporary. Writing in Scientific American, physiology professor Mark A. W. Andrews said that a likely cause of protruding veins is arterial blood pressure during exercise. Blood that would otherwise be resting in capillaries is forced out by the pressure into the surrounding muscle. That process—called filtration—makes the muscles swell, which pushes nearby veins closer to the skin's surface so they take on a bulging appearance. The process is more noticeable in athletes and body builders with very little subcutaneous fat.

arrow
The Body
11 Amazing Facts About the Nipple

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.

Despite its relatively small size on the human body, the nipple gets a lot of attention. Biologically, the nipple serves two key functions: In women, nipples deliver milk out of the ducts within the breast to babies, and for women and men, they serve as erogenous zones. Check out our list of fascinating facts about this often-misunderstood body part.

1. THE NIPPLE HAS ITS OWN SWEAT GLANDS.

The nipple is the raised bump or protrusion on top of the breast that sits on the circular area known as the areola. The areola is often much larger in circumference than the actual nipple, as it holds small sweat glands called Montgomery glands (named for William Fetherstone Montgomery, an Irish obstetrician who first described them). The sole function of these glands is to secrete fluids during breastfeeding to lubricate the nipple and to produce a scent that attracts the baby to its mother's breast.

2. NIPPLES CAN POKE IN OR OUT.

Not all nipples point jauntily outward. Men's and women's nipples can be inverted, essentially pointing inward. In the worst-case scenario, "the skin adheres to itself and has to peel open to [turn outward] initially, and [that] can be painful," Constance Chen, a board-certified plastic surgeon and clinical assistant professor of plastic surgery at Weill Cornell Medical College in New York, tells Mental Floss. For most women, however, an inverted nipple causes neither pain nor prevents breastfeeding with proper technique or nipple shields.

3. SOME PEOPLE HAVE EXTRA NIPPLES.

While most people have two nipples, one atop each breast (yes, both women and men have breasts), some people have extra or "supernumerary" nipples outside of the typical location. One Indian man was even found to have seven.

Leigh Anne O'Connor, a certified lactation consultant in New York, says these extra nipples can appear on or below an area named the Tail of Spence (after Scottish surgeon James Spence), which extends from the breast up into the armpit.

"Some people have nipples in their armpits, or even tiny breasts, and these nipples may leak," O'Connor tells Mental Floss. But an extra nipple is just an extra nipple—no cause for alarm or shame.

4. HERE'S WHY MEN HAVE NIPPLES.

Since the main purpose of nipples is breastfeeding babies, and male breasts do not lactate, it begs the question: Why do men have nipples? Scientists Stephen Jay Gould and Richard C. Lewontin tried to get to the bottom of this conundrum in a seminal paper in 1993.

All human embryos start out essentially the same. If the embryo has XY chromosomes, a gene on the Y chromosome called SRY will activate within a couple weeks of conception and begin to differentiate the embryo into one with male genitals.

However, it turns out that breast tissue begins to develop before SRY kicks in, and since nipples in men essentially do no harm, Gould and Lewontin argue, there has simply never been a good enough reason—evolutionarily speaking—to do away with them. They linger because they're benign. Or as Andrew M. Simons, a professor of biology at Carleton University in Ottawa, Ontario wrote in Scientific American, "The presence of nipples in male mammals is a genetic architectural by-product of nipples in females. So, why do men have nipples? Because females do."

5. THE WORLD'S STRONGEST NIPPLES BELONG TO THE GREAT NIPPULINI.

Who needs pecs when you have nipples like those of The Great Nippulini, a.k.a. Sage Werbock, a performer who makes a living demonstrating the mighty power of his nipples? Each nipple can lift 70 pounds, and he holds a Guinness record for the heaviest vehicle pulled by nipples for 20 meters (66 feet)—988.5 kilograms (2179.27 pounds). He has also lifted a variety of dumbbells, anvils, and bowling balls.

6. THEY'RE VERY SENSITIVE TO STIMULATION.

It's no secret that many people take sexual pleasure from nipple stimulation. However, Michael Reitano, an expert in sexual health and wellness at Roman Health in New York, brings up a study published in 2011 in which researchers set out to map the neurology of sexual stimulation in women. Through MRI imaging, they determined that "when [the nipple is] stimulated, the sensations travel to the same part of the brain that is stimulated when the clitoris, vagina, or cervix is stimulated," Reitano says. The study, published in the Journal of Sexual Medicine, also confirmed that it was possible for some women to have an orgasm by nipple stimulation alone.

While the same brain mapping has not yet been done on men, "there is every reason to believe that it has some capacity to function as a source of sexual pleasure for men as well," Reitano tells Mental Floss.

7. NIPPLES ARE AS UNIQUE AS FINGERPRINTS.

Nipples come in many colors, including pale pink, reddish-beige, brown, and black. Your own two nipples can even vary from each other, as can the areolae. "They also come in many different shapes," O'Connor says. "Some are more flat, while others can be quite bulbous. A person can have two nipples that look very different from each other. Asymmetry is normal."

8. A SPECIFIC KIND OF BREAST CANCER TARGETS THE NIPPLE.

While most forms of breast cancer affect the whole breast, Paget disease of the breast is a rare cancer that targets the skin and ducts of the nipple. "Most patients get a rash on the nipples that looks like a severe case of eczema. It is a cancer of breast epithelial (skin) cells," Chen says. Paget disease of the breast represents between 0.5 and 5 percent of all breast cancers.

9. AFTER MASTECTOMY, NIPPLE SENSATION CAN OCCASIONALLY BE RESTORED.

In breast cancer cases where mastectomy—removal of the breast—is necessary, it is sometimes possible to spare the nipple, allowing for a more realistic post-treatment reconstruction, though sensation is often lost. However, Chen says that in certain cases, "it is possible to restore sensation to the nipples with nerve repairs and nerve grafts when a woman undergoes natural tissue breast reconstruction. Sensory restoration to the nipple after mastectomy is very cutting edge, but if you find the right surgeon, it is possible."

10. NIPPLE STIMULATION CAN HELP INDUCE LABOR IN PREGNANT WOMEN.

When a woman is ready to give birth but the baby isn't, one piece of often-shared advice is to stimulate the mother's nipples to induce labor. A 2005 analysis of six trial studies found a significant decrease in the number of women who hadn't gone into labor after 72 hours. Just under 63 percent of the women who received stimulation were not in labor versus 94 percent who hadn't received it.

The mechanism isn't entirely clear, but breast stimulation causes the uterus to contract. It may also help release the hormone oxytocin, which can start contractions. Once the baby's born, the baby's suckling also has benefits for the mother. "When a newborn suckles, the increased oxytocin causes the uterus to contract [and shrink to its original size over the subsequent weeks] following birth," Reitano explains.

11. BREAST MILK HAS MULTIPLE WAYS TO EXIT THE NIPPLE.

If you've ever pumped your own breast milk or seen it done, you may have noticed that the milk doesn't just come out in a single stream. In a typical nipple, "There are between four and 20 outlets for the milk to come out—it can look like one stream or [coming from] various holes," O'Connor says.

SECTIONS

arrow
LIVE SMARTER