Chiari-like malformation is an inherited condition found in the Cavalier King Charles Spaniel, Chihuahua, Yorkshire Terrier and other breeds of dog. In simplest terms it is the abnormal growth of bone in the skull which puts pressure on on the brain. This is linked to Syringomyelia (SM) in the Cavalier which is pockets of fluid in the spine. This disease is painful and often progressive meaning it gets worse over time. Treatment typically involves pain medication for relief of symptoms.