Their names Chang and Eng. These brothers from Siam, located in present-day Thailand, were literally attached to each other - their bodies were a single entity.
the name of congenital anomalies was given in honor of the two men, known as "Siamese twins".
Siamese twins are often called fusedtwins, but the term is not quite correct. The bodies of these people are not fused in the womb, they are formed and developed in this way initially. According to medical statistics, for every 200 000 deliveries, there is one such case. However, more than half of these children are doomed to die in infancy, and most of all happens miscarriage, but about 25% survive.
Look similar anomaly may differently. Gemini can be connected from the waist to the sternum, in the chest cage, back, There are even cases when the United found themselves head.
What Why are born conjoined twins
The reasons for the occurrence of the birth of such people scientistsI thought for a long time. For example, a surgeon frantsuzcky XVI century. A.Pare thought it was the result of a "wrath of God", or improper behavior during pregnancy: a woman wearing tight clothes, sitting incorrectly. Get close to the true reasons for the first time in the twentieth century could Held Brosheld.
This German researcher experimentedon the embryos of frogs, one transplanting embryos of other particles. In most cases, they died, but some survived and turned into Siamese twins. This meant that in the cell array, which is formed by the division of the zygote, there is some organizer who manages its self-organization. In humans, this process, known as gastrulation begins within 12 days after conception.
After experiments H.Brosheld took several decades of research to understand how the organizer. This clump of cells located near the dividing embryo deep furrows. In 1994, selected from the genes of the host tissue were identified signaling molecules. Thanks to them, the embryo cells are in contact with this tissue obtained "team" that determine their further development.
Total of seven molecules, and one of them -retinoic acid. How it works, can be seen in this experiment: pull the tail of a tadpole and treat the wound of retinoic acid. Instead of a tail will grow somewhat. If too much of retinoic acid, also in human embryonic body having excess until complete doubling. Excess another signal substance, called «N-sonic», leading to a doubling of the face.
Here and there are Siamese twins. The principle of "that which is hidden in a normal, apparently in pathology" has them most directly related.
Can anyone help Siamese twins
To say that life is hard Siamese twins -so do not say anything. Until late in the path of such people was one - in the fair booth or at the circus arena. Who cares about their health, as well as other people with disabilities. But is it possible to give them a full human life, dividing surgically?
Alas, not always. It is impossible to divide the twins if they have a common heart, liver or other vital organs. But at the end of the XVII century. German physician Koenig divided Siamese twins connected by only the skin, fatty tissue and connective tissue. In 1888, France was able to divide the Indian girls and Raditsu Doditsu. One of the sisters was ill with tuberculosis, and the operation done for the sake of another. However, a healthy sister survived only sick for two years.
Sometimes the birth of Siamese twins raises complex moral issue: to save one of the children can only be sacrificed to others.
Modern surgery allows even splittwins with conjoined heads, however, only a quarter of patients survive. Patients understand this and often say, agreeing to surgery: better death than such a life!