A case of monocephalus, tetrabrachious and tetrapod in female newborn goat.

All conjoined twins are originally born as a result of fertilizing one zygote (egg) and also called monozygotic twins experiencing an incomplete division of an embryo into two portions of the embryo usually causing the formation of the primary streak stage. The main reason for the creation of this defect is not obvious. Dead twin goat with one head, one trunk, four anterior limbs, and four posterior organs was referred to the Laboratory of the Faculty of Veterinary Medicine, Islamic Azad University, Shoushtar Branch, Shoushtar, Iran. The radiographic and three-dimensional images showed one normal skull and pelvic bone vertebral column. The ribs and sternum of the newborn goat were quite normal and confirmed two pairs of extra limbs. There were no doubles in describing the internal organs. This report seems to be the first report regarding a case of a monocephalus, tetrabrachius, and tetrapod newborn goat.