They were called by Chiang and Ang. These brothers from the city of Siam located in the territory of modern Thailand in literal sense were attached to each other – their bodies represented a whole. In honor of these two the name of the congenital anomaly known as "Siamese twins" was given.
Siamese twins are quite often called accrete twins, but the term is not quite correct. Bodies of such people do not grow together in a maternal womb, they are formed and develop in such look initially. According to medical statistics, one such case is the share of each 200,000 childbirth. However, more than a half of such children are doomed to death in infancy, and most often in general there is an abortion, but about 25% are possible to survive.
The similar anomaly can look differently. Twins can unite from a waist to a breast, in the area a heap of a cage, a back, even cases when connected were heads are known.
What Why Siamese twins are born
Scientists thought of the reasons of emergence of the birth of such people long ago. For example, the French surgeon of the 16th century A. Paré considered it result or "anger of the Lord", or the wrong behavior during pregnancy: the woman wore close clothes, incorrectly sat. Could approach the true reasons for the first time in the XX century Helda Brosheld. This German researcher experimented over embryos of frogs, replacing some embryos of a particle of others. In most cases they perished, but some survived and turned into Siamese twins. It meant that in the cellular massif which is formed as a result of division of a zygote there is a certain organizer who operates his self-organization. The person has this process called a gastrulation, begins in 12 days after conception. After experiments H. Brosheld was required several decades of researches to understand how the organizer acts. It is the lump of cages located near the deep furrow dividing an embryo. In 1994 the fabrics organizers emitted from genes were emitted alarm molecules. Thanks to them embryo cages at contact with this fabric receive the "teams" defining their further development. In total such molecules seven, and one of them – retinovy acid. As she acts, it is possible to track on such experience: to tear off a tail to a tadpole and to treat the wound retinovy acid. Instead of one tail will grow a little. If there is too much retinovy acid, the human embryo has excess parts of a body, up to full doubling too. The excess of other alarm substance called "N-sonic" leads to doubling of the person. Here and there are Siamese twins. The principle "what is hidden normal is obvious in pathology" has a direct bearing on them.
Whether it is possible to help Siamese twins
To tell that life of Siamese twins is heavy – means, to tell nothing. Till the latest time such people had a way one – in buffoonery or on the circus arena. Now care for them, as well as about other disabled people. But whether it is possible to present them full-fledged human life, having divided a surgical way? Alas, not always. It is impossible to divide twins if they have the general heart, a liver or other vitals. But at the end of the 17th century. The German doctor Kenig divided the Siamese twins connected only by leather, fat cellulose and connecting fabric. In 1888 in France it was succeeded to divide the Indian girls Raditsu and Doditsu. One of sisters had tuberculosis, and operation was performed for the sake of rescue another. However, the healthy sister endured the patient only for two years. Sometimes the birth of Siamese twins raises a difficult moral question: it is possible to save one of children, having only offered another. The modern surgery allows to divide even twins with the accrete heads, however, only a quarter of patients survives. Patients understand it and quite often speak, agreeing to operation: better death, than such life!