MORPHOLOGICAL ANALYSIS OF CERVICAL-VERTEBRAE IN ATAXIC FOALS

Morphological differences between cervical vertebrae were statisticall y analyzed in ataxic foals to clarify abnormal structural factors in t he pathogenesis of this problem. At first, multiple regression analysi s and cluster analysis were performed with 28 variables in C3-C7 of 39 control foals without lameness. As a result, there were no sex differ ences in the growth of all cervical vertebral sites, and the most suit able categorization of the age of the foals was 3 clusters of 8 months old or younger, 9-12 months old and 13 months old or older in any sit es in the cervical vertebrae. Twenty-eight ataxic and 19 control foals at the age of 13 months or older were then used for discriminant anal ysis with 20 variables. As a result, 1-7 variables on C3-C7 were selec ted for sufficient discrimination, in which the heights of the cranial and caudal orifices of the spinal canal, longitudinal length of the v ertebral head and height of the vertebral fossa strongly contributed t o the discrimination of all the cervical vertebrae. In addition, the w idths and longitudinal diameters of the articular processes on articul ar surfaces strongly contributed to the discrimination of the caudal r egion of the neck. In conclusion, it was suggested that the lesion in the cervical spinal cord observed in ataxic foals was caused by morpho logical abnormalities including osteochondrosis and subsequent degener ative joint disease in the cervical vertebrae.