Watson A G, Mayhew I G
Spine (Phila Pa 1976). 1986 May;11(4):334-9. doi: 10.1097/00007632-198605000-00007.
Familial occipitalization of the atlas with atlantalization of the axis was defined as a single congenital disease in Arabian horses following a clinical, radiologic, and morphologic study of 16 horses with congenital malformations of the occiput, atlas, and axis, and from a study of three reported cases. The constant morphologic features were interpreted as congenital atlantooccipital fusion, hypoplasia of the atlas and dens, malformation of the axis, and modification of the atlantoaxial joint. Atlantoaxial subluxation was also a frequent finding. The clinical syndromes shown by these horses were variable but were broadly classified into four groups. Neurologic signs varied from symmetric ataxia, with hypometria and tetraparesis to tetraplegia. These often progressive clinical signs were due to a progressive and focal compressive myelopathy of the proximal cervical spinal cord. Pedigree analysis demonstrated the familial nature of this occipitoatlantoaxial malformation seen in horses of only the Arabian breed.
在对16匹患有枕骨、第一颈椎和第二颈椎先天性畸形的马匹进行临床、放射学和形态学研究，并对3例报告病例进行研究后，家族性第一颈椎枕骨化伴第二颈椎寰椎化被定义为阿拉伯马的一种单一先天性疾病。恒定的形态学特征被解释为先天性寰枕融合、第一颈椎和齿突发育不全、第二颈椎畸形以及寰枢关节改变。寰枢半脱位也是常见表现。这些马匹所表现出的临床综合征各不相同，但大致可分为四类。神经学症状从对称性共济失调、运动减少和四肢轻瘫到四肢瘫痪不等。这些通常呈进行性的临床症状是由于颈段脊髓近端进行性局灶性压迫性脊髓病所致。系谱分析表明，这种枕寰枢畸形仅在阿拉伯马品种中具有家族性。
