Schlegel Katharina, Parry Andrew T, Lamb Christopher R, Kneiss Sibylle, Probst Alexander, Tichy Alexander, Mayrhofer Elisabeth
Department für Kleintiere und Pferde, Veterinärmedizinische Universität Wien.
Berl Munch Tierarztl Wochenschr. 2010 Sep-Oct;123(9-10):425-30.
To investigate variations in atlas shape in dogs the image archives of the Department for Small Animals and Horses, University of Vienna, and The Royal Veterinary College, University of London were searched for radiographs and CT images of the canine atlas. 32 radiographic and 78 CT studies, including 51 toy and 54 large breed dogs, were retrieved and analysed. Five dogs had both radiographs and CT scans. Patients with pathologic alterations, such as fractures and incomplete ossification of the atlas, as well as oblique projections were excluded. Compared to large breed dogs (body weight more than 30 kg) the atlas of toy breed dogs (body weight less than 10 kg) had a reduced craniocaudal and an increased dorsoventral diameter. The vertebral longitudinal axis appeared to be dorsorotated, resulting in a steeper rise of the atlas wings and a more dorsally located lateral vertebral foramen. When comparing the atlas of toy and large breed dogs, the distribution of three morphologic parameters was statistically different: Ratio length to height (toy breeds > 1, large breeds < or = 1), shape of the vertebral chanal (toy breeds: vertically oval, large breeds: round resp. cross-oval, or vertically oval) and trabecular bone of the dorsal arch (toy breeds: absent, large breeds: present). There was no significant difference in the morphology of the ventral arch. Differences in atlas morphology could contribute to the predisposition of toy breed dogs to atlanto-axial instability; however, further studies are necessary to test this hypothesis.
为了研究犬寰椎形态的变异情况，检索了维也纳大学小动物与马科系以及伦敦大学皇家兽医学院的图像档案，以获取犬寰椎的X光片和CT图像。共检索并分析了32份X光片研究和78份CT研究，其中包括51只玩具犬和54只大型犬。有5只犬同时有X光片和CT扫描图像。排除了有病理改变（如骨折、寰椎骨化不全）以及斜位投影的患者。与大型犬（体重超过30千克）相比，玩具犬（体重小于10千克）的寰椎颅尾径减小，背腹径增大。椎骨纵轴似乎背侧旋转，导致寰椎翼的上升更陡，且外侧椎间孔位置更靠背侧。比较玩具犬和大型犬的寰椎时，三个形态学参数的分布存在统计学差异：长宽比（玩具犬>1，大型犬<或=1）、椎孔形状（玩具犬：垂直椭圆形，大型犬：圆形或交叉椭圆形，或垂直椭圆形）以及背弓的小梁骨（玩具犬：无，大型犬：有）。腹弓形态无显著差异。寰椎形态的差异可能导致玩具犬易患寰枢椎不稳定；然而，需要进一步研究来验证这一假设。
