Morphological study of cephalothoracopagus deradelphus type conjoined twins. A case report.

Cephalopagus is a rare variety of conjoined twins. They are fused with their heads, thoracic and upper abdominal cavities. The exact mechanism for development of conjoined twins cannot be clearly explained. It appears that there is an alteration in the normal developmental process of monozygotic twins, which fail to separate from each other. We present the morphology of a cephalothoracopagus, revealed through anatomical dissection, emphasizing the arrangement of the viscera in the thoracic and abdominal cavities. They are fused with their heads, thoracic and upper abdominal cavities. The lower abdomen and pelvic cavities are free. Each twin has two upper and lower limbs, normally shaped. Each twin has a heart and two lungs. There is a single pharynx, esophagus and stomach, but normal lower abdominal systems. The genital and urinary systems are apparently normal. Due to the fusion of the heads and abnormal arrangement of the superior central nervous system, surgery is not attempted in these cases, the prognosis being very poor.