Morphological changes caused by pressure on the spinal cord.

The morphological changes in the spinal cord caused by pressure are described in a series of domestic animals of various species. Three types of lesion are distinguished: totally malacic, partially malacic, and non-malacic. In the non-malacic lesion changes are predominantly in the white matter and consist of de-myclination and hyalinisation of small vessels. The possibility that the immediate cause of such non-malacic lesions may be obstruction of venous drainage from the spinal cord is discussed.