Occipital dysplasia in Yorkshire terrier dogs - morphometric criteria

摘要

The aim of this study is to examine the morphology of the foramen magnum and the first cervical vertebra in Yorkshire terrier dogs in which a key hole-shaped foramen magnum had already been recognized. Another aim was to determine parameters for the anatomical structures of the craniocervical junction which had an effect on occipital dysplasia. Cadavers of three adult female terrier dogs fixed in 10% formaldehyde was examined after the owners requested their dogs for euthanasia due to neurologic symptoms. The degree of skull index (IC), occipital index (IPF), dysplasia (ISD), notch index (IWD), foramen magnum index (IOW) and new biometric criterions introduced by authors of the study i.e. atlas index (IC1) and dens of axis index (IZC2) were determined. The study showed that the foramen magnum index provides a direct numerical information about the size and shape of the foramen. The foramen magnum index descriminates neurologically symptomatic dogs from asymptomatic dogs. Nonetheless, all four indices used in craniometer should be calculated. The result of this study indicates that the occipital dysplasia had an effect on the stability of the craniocervical junction and therefore atlax index (IC) and dens of axis index IZC2 should be determined.