Wilson W D, Hughes S J, Ghoshal N G, McNeel S V
J Am Vet Med Assoc. 1985 Jul 1;187(1):36-40.
Occipitoatlantoaxial malformation was diagnosed in a 19-month-old mare of Appaloosa breeding and in a 3-year-old Quarter Horse gelding. Both horses had abnormal head and neck carriage since birth, but neurologic deficits did not become evident clinically until the horses reached 2 and 3 years of age, respectively. Palpation and manipulation of the base of the skull and cervical area proved to be useful diagnostically. Movement could not be elicited at the atlantooccipital joint but, in comparison with clinically normal horses, the range of dorsoventral motion at the atlantoaxial joint was increased. Alternate subluxation and relocation of this joint generated audible clicking sounds. Radiography revealed symmetric atlantooccipital fusion, with modification of the atlas, atlantoaxial joint, and axis. These findings were confirmed at necropsy.
一匹19个月大的阿帕卢萨马种母马和一匹3岁的夸特马 gelding被诊断出患有枕寰枢椎畸形。两匹马自出生以来头部和颈部姿势异常，但直到分别达到2岁和3岁时，神经功能缺损才在临床上明显表现出来。对头骨基部和颈部区域进行触诊和手法检查在诊断上很有用。寰枕关节无法引发活动，但与临床正常的马匹相比，寰枢关节的背腹运动范围增加。该关节的交替半脱位和复位产生了可闻及的咔嗒声。放射学检查显示寰枕关节对称融合，并伴有寰椎、寰枢关节和枢椎的改变。这些发现经尸检得到证实。
