Craniomandibular osteopathy is a disorder that occurs in young dogs, primarily terriers. The most commonly affected breeds are West Highland White Terriers, Scottish Terriers and Cairn Terriers. It has been recognized in other terrier breeds and in Boxers, Labs, Great Danes and Dobermans. It usually shows up before 10 months of age.

Excessive bone development occurs along the mandible (jaw) and the temporal region. Affected dogs have difficulty chewing and swallowing and may drool as a result of this. There can be great pain on opening the mouth but some dogs do not seem as pained as others. There is often fever accompanying this disorder. Weight loss can occur from the difficulty in eating. Atrophy (shrinking) of the muscles over the head and jaw areas can occur. X-rays show excessive bone production, sometimes very severe.