Conjoined twins, otherwise known as Siamese twins, are probably the most well known sideshow performer of the past. Famous examples
include the original 'Siamese' twins, Chang & Eng Bunker, and film stars Daisy & Violet Hilton. Due to advances in surgical techniques,
many twins can now be separated at birth, although unfortunately, death is still common.
Types
There are quite a few types of conjoined twins, some more common than others:
Cephalopagus - Part of the upper body is joined, and the heads are also connected, with the faces on opposite sides. This is an extremely rare type. Craniopagus - Skulls are conjoined, and two seperate brains are fused. About 2% of cases, although some are now successfully separated. Craniothoracopagus - Twins joined at the head and chest, with only one brain and fused hearts and gastrointestinal tracts Dicephalus - A single body, but two separate necks and heads. Usually both brains can control the shared body. Example: Brittany and Abigail Hensel Fetus in Fetu - An undeveloped fetus is contained inside the body of its developed twin. Ischopagus - Connection of the lower half of the body, usually the coccyx and sacrum. Around 6% of conjoined twins. Omphalopagus - Twins are joined from the waist to the breastbone. This is the second most common type, around 30%. Parasitic Twin - One of the twins is smaller, underdeveloped and deformed, and is dependent on its developed sibling. Parapagus/Diprosopus - Connection of the lower half extending various distances upwards. Around 5% of all conjoined twins. Pygopagus - Common type in which the twins are connected at the posterior at the rump. 20% of all cases are this type. Thoraco-Omphalopagus - A combination of Thoracopagus and Omphalopagus. Thoracopagus - The most common type, making up around 40% of all cases. Connection is at the chest, and often involves sharing the heart, thus survival of both past infancy is very unlikely.
Other Facts
-Conjoined twins occur when a single fertilized ovum doesn't separate properly. As they are from the same egg, the twins are always identical. Conjoined twins cannot occur when the twins come from separate eggs.
-They are most often female, at a ratio of 3:1.
-They are most likely to occur in India and Africa.
-Occurance is 1 in every 200,000 live births.
-No documented cases of conjoined triplets or quads exist.
-Conjoined twins have been artificially created in amphibians.
-Genetic and environmental conditions are the main influences on the creation of conjoined twins.
Conjoined twins, otherwise known as Siamese twins, are probably the most well known sideshow performer of the past. Famous examples
include the original 'Siamese' twins, Chang & Eng Bunker, and film stars Daisy & Violet Hilton. Due to advances in surgical techniques,
many twins can now be separated at birth, although unfortunately, death is still common.