Polycephaly is the condition of having more than one head. ... In craniopagus parasiticus, the two heads are joined directly to each other, but only one head has a functional torso. Survival to adulthood is rare, but does occur in some forms of dicephalus
What causes Bicephaly?
However, bicephaly can result from both genetic and environmental anomalies during the development of an embryo. Either an embryo splits in two (which is how identical twins are formed), or it splits incompletely and that's what causes conjoined twins in humans.
What does polycephaly mean?
Polycephaly is the condition of having more than one head. The term is derived from the stems poly- meaning 'many' and kephal- meaning "head", and encompasses bicephaly and dicephaly (both referring to two-headedness). A variation is an animal born with two faces on a single head, a condition known as diprosopus.
