Cephalopagus

Cephalopagus - two-body splitting of the fetus in the head area occurs when a fusion of the walls of one of the paired heads of the fetus is applied; one half of the body remains intact here, but the other half does not, since it has completely (or partially) moved to the other shoulder. The child's skull is Siamese. Similar cases have been described since the middle of the 19th century.