Some aspects of the pathology and pathogenesis of the myelopathy caused by disc protrusions in the dog.

The pathological changes in 23 cord lesions caused by disc protrusion are described. It is suggested that three broad classifications of damage can be found: (1) compressive change; (2) malacia; and (3) diffuse demyelination. The distribution of damage, within the segment, was different in each type of change as were the glial and vascular reactions. It is suggested that vascular factors play a major part in the pathology of the malacic and demyelinating lesions and may be of secondary importance in compressive lesions.