One hypothesis is that craniopagus parasiticus starts with the development of two fetuses from a single zygote that fail to separate at the head region around the second week of gestation.
12.
Rebeca is the eighth documented case in the world of craniopagus parasiticus, said Dr . Santiago Hazim, medical director at Cure International's Center for Orthopedic Specialties in the Dominican capital, Santo Domingo, where the surgery will be performed.
13.
While it is possible for a person to have two heads, the condition craniopagus parasiticus, a form of conjoined twins, sees one head upside-down on top of the other & ndash; Pi��n's " second head " was oriented like his actual head.
