title: Comparative anatomy of the cardiac foramen ovale in cats (Felidae), dogs (Canidae), bears (Ursidae) and hyaenas (Hyaenidae).
abstract: The structure of the foramen ovale from 16 species representing 4 carnivore families, the Felidae, Canidae, Ursidae and Hyaenidae, was studied using the scanning electron microscope. The Felidae were represented by 9 domestic cat fetuses (Felis catus), 2 snow leopard neonates (Uncia uncia), an ocelot neonate (Leopardus pardalis), 2 lion neonates (Panthera leo), a panther neonate (Panthera pardus) and 3 tigers (Neofelis tigris), comprising 2 fetuses and a neonate. The Canidae were represented by a golden jackal neonate (Canis aureus), a newborn wolf (Canis lupus), 8 domestic dog fetuses (Canis familiaris), 3 red fox neonates (Vulpes vulpes) and a dhole neonate (Cuon alpinus). The Ursidae were represented by a brown bear neonate (Ursus arctos), a day-old grizzly bear cub (Ursus arctos horribilis), a polar bear neonate (Ursus maritimus), and 2 additional bear fetuses (species unknown). The Hyaenidae were represented by a striped hyaena neonate (Hyaena hyaena). In each species, the foramen ovale, when viewed from the terminal part of the caudal vena cava, had the appearance of a short tunnel. A thin fold of tissue, the developed remains of the embryonic septum primum, extended from the distal end of the caudal vena cava for a variable distance into the lumen of the left atrium and contributed towards the 'tunnel' appearance in all specimens. It constituted a large proportion of the tube, and its distal end was straight-edged. There was fibrous material underlying the endothelium of the flap, the apparent morphology of which suggested that it comprised cardiac muscle.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Preclinical Veterinary Sciences, Royal (Dick) School of Veterinary Studies, University of Edinburgh, UK.
authors.forename: A A
authors.initials: AA
authors.lastname: Macdonald
authors.forename: M
authors.initials: M
authors.lastname: Johnstone
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D002335:Carnivora / Q000033:anatomy & histology* / Q000196:embryology; D002415:Cats / Q000033:anatomy & histology*; D004285:Dogs / Q000033:anatomy & histology*; D006346:Heart Septum / Q000033:anatomy & histology* / Q000196:embryology; D001503:Ursidae / Q000033:anatomy & histology*