CM is almost ubiquitous in Cavalier King Charles spaniels (CKCS); Cerda-Gonzalez et al (2009) found that 92% had at least one craniocervical morphologic abnormality detected in MR images. However severity of the CM does not predict the presence of syringomyelia although Cavaliers with clinical signs from syringomyelia are more likely to have smaller cauda fossas (i.e. back of skull) volume compared to unaffected Cavaliers (Cerda-Gonzalez et al 2009).