Arteries of the head and encephalic base in a case of conjoined twin cattle

Dicephaly is a peculiar type of conjoined twins, which is observed in cattle and other vertebrates. The analysis demonstrates the course and division of arteries of the cranium of a one-day-old two-headed conjoined calf. In comparison with the normal pattern of the bovine cranial vasculature, the arteries of the head of the conjoined animal were considerably modified. The absence of the arteries found in anatomically normal cattle was compensated by very strong, modified linguofacial trunks located at the place where the animals’ heads were conjoined. Brain base arteries, head vascularity, ruminant Conjoined twins, resulting from a malformation of monozygotic twins, have been known at least since 6500 BC (Mellaart 1962). This condition is caused by an incomplete division of the embryo during the embryogenesis (Wagner et al. 2013). Dicephaly (dicephalus; two-headed monster) is a peculiar type of conjoined twins observed in cattle (Cornillie et al. 2006; Čítek et al. 2009). The case of a two-headed bull shark described by Wagner et al. (2013) proves that this malformation has a universal character in vertebrates. In spite of the description of conjoined twins in various species of animals including the dog (Nottidge et al. 2007), sheep (Spiers et al. 2010; Omobowale et al. 2014), goat (Shojaei et al. 2012), pigeon (Corbera et al. 2012) and shark (Wagner et al. 2013), there is a lack of analyses of the arterial architecture of the areas of abnormalities. The aim of this study was to describe the arterial vascularisation in a case of conjoined twin cattle, including the arteries of the encephalic base, and to compare this pattern with the anatomically normal head vascularisation in the same species. Materials and Methods The research was conducted on a one-day-old, two-headed conjoined still-born bull calf with five limbs, born from a Polish Red-and-White cow of the Bos taurus species. A Caesarean section was carried out during calving. The investigation was conducted on a corrosion preparation of the vessels on a bone scaffold. For this purpose the arteries of the animal under investigation were filled with acetone-dissolved stained vinyl superchloride. The injection mass was infused through the heart into the brachiocephalic trunk by means of an air-cushioned syringe at a pressure of 60–80 kPa. After about 40 days the mass had hardened and the heads were enzymatically macerated (Persil® Henkel, Düsseldorf, Germany) at a temperature of 38 °C. The resulting corrosion preparations were used to analyse the course, division and connections of arteries in relation to the bone scaffold of the cranium (skeletotopia). The anatomical nomenclature used conformed to an illustrated elaboration on the anatomical nomenclature (Simoens 1978-1979).