Eight Calves of Cervical Ectopia Cordis and Their Sternums

Abstract

Four male and four female Holstein-Friesian calves affected with cervical ectopia cordis were examined macroscopically and their sternums were radiographed using soft X-rays. Their lifespan ranged from 3 minutes to 312 days. The heart was located within the pericardium under the muscles and skin at the ventral cervical area and its double apex was directed craniodorsally, and the base was pointed caudoventrally. The branching pattern of arteries from the aortic arch was similar to that of dog in all cases. Double cranial vena cava and double azygos vein were observed in many cases. The manubrium was very wide to enlarge the cranial thoracic aperture. The short and wide sternum consisted of 13 to 26 sternebrae, and the ossification centers of manubrium and body of sternum showed paired appearance. The thoracic portion of the thymus was absent, while the cervical portions were gathered together on the craniodorsal side of the heart. The ligaments extending from the fibrous pericardium were attached to the mandibles and parotid fasciae cranially, to the cervical fasciae laterally, and also to the first ribs or manubrium caudally and held the heart in its position. Based on these findings, the pathogenesis of this anomaly was discussed from an embryological point of view.