Sirenomelia

Sirenomelia (lat. sirenomelia; other-Greek. σειρήν — siren + μέλος — part of the body, limb) (syn.: mermaid syndrome, simpus, siren) — a developmental abnormality in the form of a fusion of the lower extremities. The limbs grow together in such a way that they look like the tail of a fish, and the child himself looks like a mermaid or a siren (hence the name). Also, the external genitalia are often absent, the gastrointestinal tract is underdeveloped and the anus is not perforated.

It occurs in one case per 100,000 births and usually leads to death 1-2 days after birth due to abnormalities in the development and functioning of the kidneys and bladder. However, there are cases when children with sirenomelia (without surgery) lived for several years.

There are two known people in the world who survived a surgical operation and managed to recover.

Until the 19th century, for centuries, the bodies of children suffering from syrenomelia could be used to create stuffed "sea maidens", which remained one of the main exhibits of the so-called cabinets of curiosities.