title: Occipitoatlantoaxial malformation with duplication of the atlas and axis in a half Arabian foal.
abstract: An unusual occipitoatlantoaxial malformation is described in a 2-week-old male part Arabian foal that was unable to stand at birth and showed signs of spastic tetraparesis due to a cervical spinal cord compression. There were 2 atlases present. One was fused to the occipital bones. The other articulated with the first atlas and an axis which had a long dens that projected into the vertebral canal. Examination of the ossification centers of the axis indicated partial duplication of that bone.
authors.affiliation: Department of Anatomy, New York State College of Veterinary Medicine, Cornell University.
authors.forename: A
authors.initials: A
authors.lastname: de Lahunta
authors.forename: C
authors.initials: C
authors.lastname: Hatfield
authors.forename: A
authors.initials: A
authors.lastname: Dietz
mesh_terms: D000015:Abnormalities, Multiple / Q000150:complications / Q000000981:diagnostic imaging / Q000196:embryology / Q000662:veterinary*; D000818:Animals; D001268:Atlanto-Axial Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging; D001269:Atlanto-Occipital Joint / Q000002:abnormalities* / Q000000981:diagnostic imaging; D006736:Horses; D008297:Male; D011859:Radiography; D013117:Spinal Cord Compression / Q000000981:diagnostic imaging / Q000209:etiology / Q000662:veterinary