Atlantoaxial subluxation and absence of transverse ligament of the atlas in a dog
Watson, A.G.; de Lahunta, A.
Journal of the American Veterinary Medical Association 195(2): 235-237
1989
ISSN/ISBN: 0003-1488 PMID: 2768042 Document Number: 334658
Absence of the transverse ligament of the atlas was diagnosed at necropsy in an 8-month-old Shih Tzu with radiographic signs of atlantoaxial subluxation. Symmetric ataxia, tetraparesis, and signs of pain in the vertebral canal suggested a lesion in the cervical portion of the spinal cord. Necropsy revealed absence of the transverse ligament of the atlas and malformation of dens and atlas. In addition, the alar ligaments were distinct and thick, and the atlanto-occipital and atlantoaxial joint capsules were markedly thicker than normal. Histologic examination revealed focal compressive myelopathy of the spinal cord at the level of the atlantoaxial joint.