Mayhew I G, Watson A G, Heissan J A
Equine Vet J. 1978 Apr;10(2):103-13. doi: 10.1111/j.2042-3306.1978.tb02232.x.
From a clinical, radiological and morphological study of 9 horses with congenital malformations of the occiput, atlas and axis, and from a study of 2 reported cases, 3 diseases were defined: A. Familial occipitalisation of the atlas with atlantalisation of the axis in Arabian horses (7 cases in this report and the case reported by Leipold, et al., 1974). These horses had congenital atlantooccipital fusion, hypoplasia of the atlas and dens, malformation of the axis and modification of the atlantoaxial joint. B. Congenital asymmetrical occipitoatlantoaxial malformation (2 cases in this report). A Standardbred and a Morgan horse had atlantooccipital fusion, a wedge shaped vertebral piece attached to the caudal end of the axis and sigmoid scoliosis of the cervical vertebrae. C. Asymmetrical atlantooccipital fusion (the case reported by Schmaltz, 1915). This horse of an unknown breed had asymmetrical fusion between the atlas and occiput and cervical scoliosis. The clinical syndromes shown by horses with these malformations were variable but were broadly classified as: 1. Foal dead at birth, seen in one foal with A. 2. Tetraparesis at birth, seen in 5 foals with A. These foals were born with signs varying from tetraparesis to tetraplegia. 3. Progressive ataxia, seen in 2 foals with A. Clinical signs were due to a progressive focal cervical compressive myelopathy. 4. Congenital cervical scoliosis/deviated head, seen in the 2 horses with B and the horse with C. These horses had no signs of spinal cord or brain disease. The diagnoses were made clinically by palpation of the occipitoatlantoaxial region and were confirmed radiographically and/or by post mortem examination in all except one case. Pedigree analysis showed the familial nature of the particular occipitoatlantoaxial malformation seen in horses of only the Arabian breed.
通过对9匹患有枕骨、寰椎和枢椎先天性畸形马匹的临床、放射学和形态学研究，以及对2例已报道病例的研究，确定了3种疾病：A. 阿拉伯马的寰椎枕化伴枢椎寰椎化（本报告中有7例，以及Leipold等人于1974年报道的病例）。这些马匹存在先天性寰枕融合、寰椎和齿突发育不全、枢椎畸形以及寰枢关节改变。B. 先天性不对称枕寰枢椎畸形（本报告中有2例）。一匹标准赛马和一匹摩根马存在寰枕融合、一块楔形椎骨附着于枢椎尾端以及颈椎乙状侧弯。C. 不对称寰枕融合（Schmaltz于1915年报道的病例）。这匹品种不明的马存在寰椎与枕骨之间的不对称融合以及颈椎侧弯。患有这些畸形的马匹所表现出的临床综合征各不相同，但大致可分为：1. 出生时死亡的驹，在患有A疾病的一匹驹中可见。2. 出生时四肢轻瘫，在患有A疾病的5匹驹中可见。这些驹出生时的体征从四肢轻瘫到四肢瘫痪不等。3. 进行性共济失调，在患有A疾病的2匹驹中可见。临床体征是由于进行性局灶性颈椎压迫性脊髓病所致。4. 先天性颈椎侧弯/头部偏斜，在患有B疾病的2匹马和患有C疾病的马中可见。这些马没有脊髓或脑部疾病的体征。除1例病例外，所有病例均通过触诊枕寰枢椎区域进行临床诊断，并通过放射学检查和/或死后检查得以证实。谱系分析表明，仅在阿拉伯马品种中出现的特定枕寰枢椎畸形具有家族性。
