1. Clínica Veterinaria Villaluenga; Villaluenga de la Sagra; Toledo Spain
2. Department of Anatomy and Embryology; School of Veterinary Medicine; Universidad Complutense de Madrid; Avda. Puerta de Hierro s/n Madrid 28040 Spain
3. Unit of Anatomy and Embryology; Department of Anatomy and Animal Production; Veterinary School; University of Santiago de Compostela; Lugo Spain