[Heterodelphus--a rare form of twin developmental defect]

The authors saw a rare developmental twin anomaly--heterodelphus. The parasite was an organism devoid of the head, fixed with its thoracic wall an epigastric area to the front wall and the epigastric area of the autosite. Respiration and palpitation of the parasite was not auscultated. The abnormal twins had a single umbilical cord. The surgical division of the conjoined twins was performed in 4 months. The operation and operative findings are described. The postoperative period was hard. At the present time the boy's state is good, he feels well and develops in accordance with his age.