قالب وردپرس درنا توس
Home / Health / BBC – Future – How modern life changes the human skeleton

BBC – Future – How modern life changes the human skeleton



It all started with a goat. The unfortunate animal was born in the Netherlands in the spring of 1939 – and his prospects did not look good. On the left side of his body, a bare patch of fur marked the spot where his foreleg should have been. On the right side, his front leg was so deformed that it was more like a stump. Running on all fours would be problematic, for example.

But when he was three months old, the little goat was adopted by a veterinary institute and taken to a meadow. There he quickly improvised his own way of moving. He pushed his back feet forward and straightened until he stood half upright on his hind legs, and jumped. The end result was somewhere between the hopping of a kangaroo and a hare, though probably not quite as majestic.

Unfortunately, the goat was involved in an accident soon after his first birthday, and he died. One last surprise lurked in his skeleton.

For centuries, scientists had believed that our bones are fixed ̵

1; that they grow predictably, as inherited from our parents. When a Dutch anatomist examined the goat's skeleton, he found that he had begun to adapt. The bones in his hips and legs were thicker than expected, while those in his ankles were stretched out. Finally, his toes and hips were unusually bent to take a more upright posture. The goat's frame had begun to look very much like those of bouncing animals.

You may also enjoy it:

Today it is a settled fact that our skeletons are surprisingly malleable. The pure white remains displayed in museums may seem solid and sluggish, but the bones under our flesh are very much alive – they are actually pink from blood vessels – and they are constantly being broken down and rebuilt. Although each person's skeleton evolves to a rough template, which is set in his DNA, it is then tailored to the particular stresses of his life.

This has led to a discipline known as "osteobiography" – literally "the biography of" bones ", in which a skeleton is looked at to find out how its owner lived. It is based on the fact that certain activities, such as walking on two legs, leave a predictable signature such. B. more stable hip bones.

And the discovery of a strange, prickly growth on the backs of many people, the realization that our jaws are getting smaller, and the enigmatic finding that German teenagers currently have tighter elbows than ever before show that modern life has one Influence on our lives has bones.

An example of the functioning of osteobiography is the mystery of the "strong men" of Guam and the Marianas: it began with the discovery of a male skeleton on Tinian Island. The remains date back to the 16th or 17th century and were undoubtedly gigantic. The skull, arm bones, collarbone and bones of his lower legs indicated that he was incredibly strong and unusually tall.

The find suited well to the local legends of giant ancient rulers who had been truly heroic to physical accomplishments. Archaeologists called him Taotao Tagga – "Man of Tagga" – after the famous mythological chief of the island, Taga, who was known for his superhuman strength.

When other graves were discovered, it became clear that the first skeleton was not an anomaly. In fact, Tinian and the surrounding islands had a race of exceptionally muscular men. But where did they get their strength from?

At the same time, the remains of strong men were often found beside the answer. In the case of Taga, he was buried between 12 imposing carved stone pillars that had originally supported his house. In the meantime, a closer examination of its bones and others has found that they have characteristics similar to those of the Tonga Archipelago in the South Pacific, where people work on much stone and build it with massive stones.

The largest house of its kind The island had columns 5 meters high and nearly 13 tons each – about as much as two adult African elephants. This was not a mysterious race of muscular giants; The men reached their powerful physiques through hard work.

In the future, if the same technique were used to synthesize people's lives in 2019, scientists would discover characteristic changes in our skeletons that reflect our modern lifestyle. [19659002] "I have been a clinician for 20 years and have only recently discovered over the last decade that my patients have this growth on their skull," said David Shahar, a health scientist at The Sunshine Coast University. Australia.

The tip-like feature, also known as the "outer posterior stump," is located at the lower back of the head, just above the neck. If you have one, you can probably feel it with your fingers – or if you have a bald head, it may even be visible from behind.

Until recently, this type of growth was considered extremely rare. When the spike was first examined in 1885, renowned French scientist Paul Broca complained that he had a name at all. "He did not like it because he had studied so many copies, and he really did not see any who had it." Together with his colleague, he analyzed more than a thousand X-ray images of skulls of people aged 18 to 86 years. They measured all the tips and noted how the attitude of each participant was.

What the scientists found was conspicuous. The peak was much more frequent than expected and even more common in the youngest age group: one in four people aged 18-30 years grew. Why could that be? And should we be worried?

Shahar believes the explosion of spikes is due to modern technology, especially our recent obsession with smartphones and tablets. As we bend over them, we straighten our necks and hold our heads forward. This is problematic because the average head weighs about 4.5 kg – about the same as a big watermelon.

Texthals

When we sit upright, these heavy objects are neatly balanced on our spikes. But if we lean forward to rummage through famous dogs on the social media, we have to make an effort to keep them in place. Doctors call the pain "Texthals". Shahar thinks the spines form because the stooped posture puts additional pressure on where the neck muscles attach to the skull – and the body reacts by laying off fresh layers of bone. These help the skull manage the extra load by spreading the weight over a larger area.

Of course, no wrong attitude was invented in the 21st century – people have always found something to bale about. Why did not we get the skull bulges from books? One possibility is how much time we currently spend on our phones compared to the time a person would have spent reading before. For example, even in 1973, long before most modern hand-held distractions were invented, the average American read about two hours each day. In contrast, people today spend almost twice that time on their cell phones.

For Shahar, the biggest surprise was actually how big the spikes were. Prior to his study, the most recent research was conducted in 2012 in an osteopathic laboratory in India. It's a laboratory that specializes exclusively in bone – as you can imagine, they have quite a few skulls – but the doctor there only found one with the growth. It measures 8mm, which is so small that it would not even have been included in Shahar's findings. "And he thought it was significant enough to write a whole newspaper about it!" He says. In his own study, the strongest growths were 30 mm long.

Interestingly, the strong men of the Mariana also tend to have growths on their skulls. They are said to have developed for a similar reason – to support their powerful neck and shoulder muscles. The men may have carried heavy weights by hanging them from rods over their shoulders.

Shahar says it's likely the modern spines will never disappear. They are getting bigger – "Imagine if you have stalactites and stalagmites and nobody bothers them, they will just keep growing" – but they rarely cause problems themselves. If there is a problem, it is probably caused by the other compensations the body has to make for all our prejudices.

On the other side of the world, scientists in Germany have discovered another bizarre development: our elbows are shrinking. Christiane Scheffler, an anthropologist from the University of Potsdam, examined body measurements of schoolchildren when she noticed the trend.

Child skeletons became more fragile from year to year.

To see exactly how her skeletons had changed Over time, Scheffler conducted a study examining how robust children were between 1999 and 2009. The "frame index" was calculated, ie the size of a person compared to the width of their elbows. Then she compared her results to those of an identical study 10 years older. She found that the skeletons of children became more fragile from year to year.

"So we thought about that," says Scheffler. Their first idea was that it could be genetic, but it's hard to see how a population's DNA could change so much in just 10 years. The second problem was that the children may have suffered from a poor diet, but this is not a real problem in Germany. The third was that today's teenagers are a generation of couch potatoes.

To find out, Scheffler, this time with several colleagues, conducted a new study in which she also asked the children to complete a questionnaire about their daily habits. and wear a tap counter for a week. The team found a strong correlation between the robustness of the children's skeletons and walking performance.

It is already known that every time we use our muscles, we increase the mass of bones that support them. "If you use them over and over again, they build up more bone tissue, which results in a higher density and a larger bone volume," says Scheffler. The shrinking skeletons of the children look like a simple adaptation to modern life, as it makes no sense to breed bones you do not need.

But there was a surprise in the data: walking was the only kind of exercise that seemed to have an impact. Scheffler says that's because even the most avid sports fans spend very little time practicing. "It does not help if your mother takes you by car for an hour or two a week," she says.

And although no-one's paid attention to whether the connection is adult, the same rules apply: it's not enough to go to the gym a few times a week without having to walk long distances. "Because our development tells us we can run nearly 30km a day."

The last surprise hidden in our bones may have happened for hundreds of years, but we just noticed. In 2011, Noreen of Cramon-Taubadel from the State University of New York studied skulls in Buffalo. As an anthropologist, she wanted to use the form to determine where she came from.

In search of an answer, Cramon-Taubadel had searched the collections of museums around the world so that skulls could compare and meticulously measure them. In fact, by and large, one could only tell from the shape of where a skull came from and to whom its owner was related. But there was one part that was not the case: the jaw.

It quickly became clear that the shape of the jaw was not genetically determined, but depended mainly on whether that person grew up with a hunter. Collecting society or a community based on agriculture. Cramon Taubadel believes that what matters is how much we chew when we grow up. "If you think of orthodontics, the reason why we do that with teenagers is obviously that their bones are still growing," says Cramon-Taubadel. "Bones are still deformable at this age and respond to different pressures."

In modern, agricultural societies, where food is soft and tasty, we can eat a meal without having to crush much first. Less chewing leads to weaker muscles, which means that our jaws do not develop so robustly. Another idea is breastfeeding, as the age at which mothers wean their children is very different and dictates when they start to chew firmer food.

In the postindustrial population, we often suffer from dental problems, such as As dental cramps and crooked teeth.

It is not yet necessary to mourn the jaws of your weak farmer. According to Cramon-Taubadel, the influence that chewing on the lower face can have is quite subtle to the naked eye. Instead, it will probably show in our teeth. "The main problem is that we are more likely to suffer from dental problems, especially in the post-industrial population – dental overcrowding, crooked teeth, etc.," she says. "Currently, research shows that a somewhat biomechanically harder diet, especially in children, can be helpful in counterbalancing some imbalance between the growth, development and penetration of our teeth."

And here's an unexpected twist. Unbelievable, now it seems that the changes in our jaws and teeth had at least one welcome side effect – the way we speak. A recent study found that when they discovered agriculture about 12,000 years ago in the Neolithic, societies may have made new sounds such as "f" and "v" by altering our bites. The researchers estimated that this changed the spoken languages ​​from just 3% of these difficult sounds to 76% today.

Instead of having bites as with the upper incisors covering the lower teeth, adults previously had bites where they met instead. To catapult your jaw back to the Neolithic, try pushing out your lower jaw until your upper and lower teeth touch, and then say, "Fish" or "Venice," examine them from their spaceships? If we are not careful, they will uncover unhealthy diets, amazing inactivity, and a pathological attachment to technology. Maybe it's best to be cremated.

Join more than one million Future fans by liking us on Facebook or follow us on Twitter or [19659046] Instagram .

If you liked this story, sign up for the weekly bbc.com newsletter titled "If You Read Only 6 Things This Week". , A handpicked selection of BBC Future, Culture, Capital and Travel stories delivered to your inbox every Friday.


Source link