Most animals have tails. Everyone knows that geckos will cut off their tails to survive in critical moments. The tail of fish can help them swim. Felines often play with their tails, but humans seem to be an exception.
Recently, a baby girl born in Mexico was found to have a 5.7 cm tail on her butt. After examination by a doctor, the baby girl was very healthy. The inside of her tail was composed of general tissue and fat, which belongs to benign tissue. When the baby girl was 2 months old, the doctor evaluated her health again. The examination showed that her development was normal, and then arranged surgery to remove the tail. At present, the baby girl is recovering, and the removal of her tail will not theoretically affect her subsequent growth and development.
I believe that many people will ask here, why does humans have no tail, but this baby has a tail?
It is generally believed that the disappearance of human tail is the result of evolution. In nature, the closest genes to humans are modern apes (orangutans, gorillas , chimpanzees and gibbons). The biggest difference between these animals and monkeys is that they have no tails and basically have the ability to walk upright.
As the human race evolved into , gradually learned to walk upright and began to use different systems to avoid falling. In this process, the tail became an obstacle to balance. After generations of natural selection, the tail is eliminated.
On the other hand, humans do not need to use their tails to store energy and nutrition like platypus , lemur , Mianyang ; there is no need to use their tails to drive away mosquitoes like cows, horses, dogs, tigers, etc., our hands can do this easily.
, the tail does not have any practical effect on humans who have successfully evolved. exists, which is reasonable , and what is lost is also the reason why it does not exist.
In fact, during embryo development, the baby will have a short tail, especially on the 31st to 35th days of pregnancy, when the developed tail can even account for 1/6 of the embryo. After that, the tail will gradually be absorbed and degenerate into four or five pieces of tail vertebrae that fuse together.
From this we can see that the baby girl born with a tail in the above article is likely to have a degeneration and incomplete tail during embryonic development, that is, the phenomenon of atlas appears. Most of these tails have tail vertebrae, with only blood vessels, muscles and nerves.
Clinically, some babies also suffer from congenital nervous system development deformities caused by myelometriacetosis, resulting in local mass in the midline of the back, neck, chest or lumbar sacral area. They may also be mistaken for being "tail" by their family members. This situation requires surgical treatment as soon as possible after a clear diagnosis, otherwise it will seriously affect the growth and development of the child.
What other atlas rebirth phenomena may occur in humans?
1.Hipsterism
Under normal circumstances, except for the head, eyebrows, armpits and private parts, only fine and inconspicuous hair is left on the skin of humans, that is, the hair in these parts has been highly degenerated. But some people can still grow thick hair all over their bodies, and even these body hairs can continue to grow. However, in addition to abduction, hairiness can also be caused by various diseases such as adrenal tumor , polycystic ovary syndrome , and differential diagnosis should be paid attention to.
2.Adjunctive
Cats and dogs and other mammals have more than two breasts, and humans also have such "gene memory" during the embryonic period, with 6 to 8 pairs of breast bases from the armpit to the groin. But like the tail, the rest will degenerate before birth except for the pair on the chest.
When the degeneration is not complete or does not degenerate, secondary breasts will appear. It can appear in the armpits on one side or both sides, or in the upper and lower breasts, abdomen, inguinal , thighs and other parts.
These secondary breasts can have only breast tissue, and can also grow nipple, and even develop into breasts that are comparable to normal breast shapes, and also nipple areola.
A side breast is a tissue with congenital abnormal development. In addition to affecting beauty and normal social interaction, it may also suffer from various breast diseases, including breast cancer. If the impact on life is obvious, it is recommended to remove it as soon as possible.
online special article of family doctors, no reprint without authorization
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