Curr Pediatr Res 2011 Volume 15 Issue 2 111 Curr Pediatr Res 2011; 15 (2): 111-115 Cardiovascular anomalies in a dicephalus dipus dibrachius twin L.C. Prasanna, S. Hussain Saheb, H. Mamatha*, M. Adibatti, S.T. Thomas, C.M. Ramesh Department of Anatomy, J.J.M. Medical College, Davangere, Karnataka, India. * Department of Anatomy, Kasturba Medical College, Manipal, Karnataka, India Abstract Conjoined twins of dicephalus type are extremely rare. We present a report of stillborn di- cephalus dipus dibrachius twin. There were two complete heads on two necks, one thorax, one abdomen, and externally normal two arms and two legs. From a thorough understand- ing of the anatomy of these twins we can gain insight into their developmental process and devise appropriate surgical strategies for separation. Key words: Conjoined twins; Dicephalus; Parapagus; Teratology. AcceptedMarch 11 2001 Introduction Dicephalus dipus dibrachius is an extremely rare form of conjoined twinning in which the infant has two arms, two legs, one trunk, but two heads. [1] Conjoined twins rep- resent one of the rarest forms of congenital anomalies with an incidence of 0.2 : 10,000 pregnancies, but only 0.05 : 10,000 live births.[2] The definitive cause of dicephalus twinning is unknown, and there are no known risk factors that are specific to this anomaly. In a study conducted by Tippi et al., 28% of conjoined twins died during intrauterine life, 54% dur- ing immediate postnatal life and 18% survived [3]. The present case is reported with an emphasis on the complex cardiovascular malformations which were noted in each twin since the architecture of the heart becomes the most vital organ during separation and survival of the twins. Case report A 24 year old woman, primigravida, at 32 weeks of gesta- tion delivered a set of conjoined twin(Fig.1) by caesarean section. The pregnancy was conceived spontaneously. The patient denied any contact with potential hazards like any teratogenic agents. There were no congenital anoma- lies in the obstetric history of the other siblings of the family. The twin had two heads and necks and fusion of the trunk below the neck with the right head is in better alignment with the spine(Fig.1&4). Both babies showed normal features with mild degree of cleft upper lip in right twin. Single pair of upper and lower limbs with no obvious congenital malformations were noted. The ab- domen was soft with a single umbilical cord containing two arteries and one vein. Examination of the genitalia showed an ambiguous genitalia and a patent anus between genitalia and coccyx bone. Posterior aspect of the twin presented meningomyelocele slightly to the left of the median plane. Babygram (Fig.4) showed two skulls and two separate vertebral columns which have an articulation with a sin- gle bony pelvis. There were two separate sets of ribs with four clavicles, of them lateral two were taking part in shoulder girdle formation and medial two overlapping each other posteriorly without giving any attachments. Autopsy findings When viewed from the posterior aspect twin 1 was on the observer’s right and twin 2 on the observer’s left. The terms “right” and “left” will hereafter be used in relation to each twin (Fig.2). Both the twins shared a common thoracic cavity with a single sternum. When the thoracic cavity was opened a common anterior mediastinum was found. On opening the pericardium, two separate, closely apposed hearts were exposed. The two cardia are placed side by side. The left heart was slightly larger than the right and were joined at the atrial levels. Four atrial appendages were present, two for each twin. The atrial complex was a