In a study published in the Journal of Comparative Pathology, researchers H.Z. Hu, C. Rusbridge, F. Constantino-Casas, N. Jeffery report that:

"SM is associated with degenerative changes in the spinal cord and may develop through primary disruption of ependymal integrity followed by vascular hypertrophy and proliferation. Glial and fibrous proliferation appears to be associated with expression of clinical signs."