title: Biomechanical properties of the atlantoaxial joint with naturally-occurring instability in a toy breed dog. A comparative descriptive cadaveric study.
abstract: The biomechanical properties of the atlanto-axial joint in a young Yorkshire Terrier dog with spontaneous atlantoaxial instability were compared to those of another young toy breed dog with a healthy atlantoaxial joint. The range-of-motion was increased in flexion and lateral bending in the unstable joint. In addition, lateral bending led to torsion and dorsal dislocation of the axis within the atlas. On gross examination, the dens ligaments were absent and a longitudinal tear of the tectorial membrane was observed. These findings suggest that both ventral and lateral flexion may lead to severe spinal cord compression, and that the tectorial membrane may play a protective role in some cases of atlantoaxial instability.
authors.affiliation: Franck Forterre, Prof., DVM, DECVS, Department of Clinical Veterinary Medicine, Small Animal surgery, Vetsuisse Faculty, University of Bern, Länggassstrasse 128, 3012 Bern, Switzerland, Phone: +41 31 6312401, Fax: +41 31 6312275, E-mail: franck.forterre@vetsuisse.unibe.ch.
authors.forename: F
authors.initials: F
authors.lastname: Forterre
authors.forename: C
authors.initials: C
authors.lastname: Precht
authors.forename: B
authors.initials: B
authors.lastname: Riedinger
authors.forename: A
authors.initials: A
authors.lastname: Bürki
mesh_terms: D000818:Animals; D001268:Atlanto-Axial Joint / Q000502:physiology / Q000503:physiopathology*; D001696:Biomechanical Phenomena / Q000502:physiology; D004283:Dog Diseases / Q000503:physiopathology*; D004285:Dogs; D005260:Female; D007593:Joint Instability / Q000503:physiopathology / Q000662:veterinary*; D008023:Ligaments, Articular / Q000502:physiology / Q000503:physiopathology; D016059:Range of Motion, Articular / Q000502:physiology
keywords: Atlantoaxial instability; biomechanics; dog