The aetiology of conjoined twins is unknown with no established risk factors. The pathogenesis is also uncertain but if cell differentiation takes place after the 14th day of embryonic development, incomplete cleavage will result in the formation of conjoined twins. A system of classification established by St Hiliaire in 1832 is still used today and is based on which structures are fused. The ...

one of the complications of twinning of mono chorionic mono amniotic gestations is conjointed twins. structural congenital malformations occur in 5 % to 7 % of twin gestations versus only 3 % of singleton births. most defects occurring in only one of the twin fetuses. occasional anomalies such as omphalocele sincenomalia heart defect one reported in both concordance. the structural defect commo...

VIEWPOINT Conjoined twins are fused twins resulting from incomplete division of a single blastocyst, 13 to16 days post fertilization (1). Complete division of a human zygote within seven days of fertilization yields identical monozygotic twins (1). Fused body components, overlapping visceral components and impaired organogenesis characterize this anomaly (1–5). Classification of conjoined twins...

Conjoined twins, the most striking anomaly of monozygosity, have always aroused extensive interest in both the medical community and the general population, owing to their rarity and unusual presentations.1 Craniopagus twins joined at the head are uncommon malformations, found once per 2.5 million live births, and represent only 2% to 6% of conjoined twins.2 In 1977, Fagan3 first reported the p...