Human vertebrae changed little at first over millions of years. But the last 200 years are visible in our vertebrae, says a recent thesis.
Human the shape of the vertebra of the spine remained almost the same for a very long time in the development of the human species. Instead, the last 200 years have already changed the human spine.
The reason is probably the decrease in exercise. This is the conclusion of the dissertation published at the University of Oulu.
“This is one possible explanation for the increase in back problems,” says the doctor Niina Korpinen. His work is in archaeology dissertationso not, for example, medicine.
I don't argue in the first, the spines of modern humans were compared with the spines of chimpanzees, gorillas and the predecessors of modern humans.
These predecessors of modern man included, among others, Neanderthal man, Malapa ape man, Rotave ape man, African southern ape man (Australopithecus africanus) and Ekembo nyanzea.
The result showed that human vertebrae are similar in shape to gorilla vertebrae. The node or body of the vertebra, to which the discs attach, has a wide oval shape in both cases. In chimpanzees it is rounder.
The shape of the human vertebra seems to have remained the same throughout the evolution of the species.
Graphics: Petri Salmén / HS, Colourbox, source; Niina Korpinen / University of Oulu
A raven suspects that the weight carried by the joints explains their shape.
“A chimpanzee weighs less than a human and moves mainly on four limbs. A gorilla, on the other hand, weighs more than a human, but it also moves on four limbs,” Korpinen reflects.
“So you could think that the stress on the back vertebrae of a person walking upright and a gorilla would be of the same order, but that of a chimpanzee is clearly lighter.”
Confounding the theory is the earliest studied hominid, who lived in Kenya in the Miocene period about 20 million years ago, Ekembo nyanzean the shape of the vertebrae.
Although this hominid was at most the size of a chimpanzee and moved on four limbs, it had broad vertebrae similar to those of later humans or gorillas.
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“We move clearly less today than 200 years ago.”
Research the second section compared the spines of present-day Finns and Finns who lived in the 18th and 19th centuries.
At a quick glance, the vertebrae look the same. But when we take into account the increased height of humans, the current spinal vertebrae turned out to be comparatively narrower and more slender than those of our first parents.
“So even though the vertebrae of the human back have remained very similar for millions of years, their shape has changed in just 200 years,” says Korpinen.
He thinks the reason lies in the change in our lifestyles.
“We move clearly less today than 200 years ago,” says Korpinen.
He considers the decrease in physical activity during adolescence, when the bones are still growing, to be particularly significant.
“Even if you move a lot later, the shape of the vertebra doesn't seem to change much after it has stopped growing.”
An observation supports the part of the dissertation in which the change in bone density with age was studied with US data from the turn of the 20th century.
A hundred years ago, the vertebrae in people's backs were denser than in people today. Especially women's vertebrae used to remain denser, even with age.
This change is also probably explained by a decrease in physical activity, Korpinen believes.
If So modern humans have lower bone density and rounder bones than our predecessors, do we perhaps have more back problems?
“This would be a justified assumption, but unfortunately there is no solid evidence for this. One way to look at this would be to compare wear and tear from the current and archaeological material, but this remains for the next studies.”
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