Craniomandibular Osteopathy
Learn what the condition is, how it may be detected early, how it is treated or managed, and which breeds or species are linked to it.
Condition snapshot
A concise guide to the condition’s pattern, detection, management and urgency.
Breeding advice appliesUse the condition’s screening guidance and veterinary or genetics advice before breeding an affected or at-risk animal.
This snapshot is a general guide, not a diagnosis or treatment plan. New, severe or worsening signs require veterinary assessment.
About the condition
Craniomandibular osteopathy is a developmental bone disorder seen mainly in young terriers, particularly West Highland White Terriers, Scottish Terriers and Cairn Terriers. It causes abnormal proliferation of bone around the mandible and other parts of the skull, including the tympanic bullae near the middle ear. The disease has a recognised inherited component in some breeds and is sometimes referred to informally as “Westie jaw” or “Scottie jaw.”
Signs usually begin while the puppy is still growing, often between three and eight months of age. The lower jaw may become thickened or enlarged, and the puppy can develop pain when opening the mouth. Chewing becomes difficult, appetite may fall and some dogs drool or resist having the head touched. If excessive bone forms around the jaw joint or skull base, the mouth may not open normally. Fever and general discomfort can occur during active phases of bone growth.
The distribution and the puppy’s age help distinguish the condition from infection, trauma or bone cancer.
A distinctive feature is that craniomandibular osteopathy is usually self-limiting. Abnormal bone proliferation tends to slow when skeletal growth is completed, commonly around one year of age. Some of the excess bone may remodel afterwards. That natural history means the main challenge is keeping the puppy comfortable and adequately nourished until the active phase passes.
Severity varies widely. Mildly affected puppies may need only temporary pain relief, while severe restriction of jaw movement can interfere with eating enough to threaten welfare. Prognosis is therefore linked to how much the abnormal bone compromises normal mouth function.
Early detection is clinical and is most relevant in predisposed terrier breeds. Because the area may be painful, gentle handling is important.
Screening & Early Detection
Craniomandibular osteopathy cannot currently be predicted in every puppy with a reliable DNA or laboratory screening test. Breeders and owners should watch growing puppies for reluctance to chew hard food, crying when yawning, excessive drooling, swelling around the lower jaw or difficulty opening the mouth.
A veterinary examination includes careful palpation of the jaw and skull and assessment of how widely the mouth can open. Radiographs are the main diagnostic test and can reveal irregular, proliferative bone around the mandible, tympanic bullae or other skull bones. Repeat imaging may be useful when early changes are subtle.
Fever, facial swelling or jaw pain can also occur with dental infection, trauma and other bone disease, so age and breed alone are not enough to make the diagnosis. A puppy that stops eating, loses weight or cannot open the mouth normally should be assessed promptly.
Family history is useful for breeding decisions because of the inherited association in affected terrier lines. The absence of a screening test does not mean affected puppies should be bred from later simply because their clinical signs resolved after skeletal maturity.
Radiographs show characteristic irregular new bone around the mandible and other skull structures. In uncertain cases, additional imaging or biopsy may be considered.
Treatment & Management
Treatment is mainly supportive because abnormal bone growth usually slows as the puppy reaches skeletal maturity. Pain relief is central. A veterinarian may prescribe anti-inflammatory or other analgesic medication so that the puppy can eat, sleep and move the jaw more comfortably. Medication should be adjusted to the individual dog and monitored during prolonged use.
Food may need to be softened or offered in a form that requires minimal chewing. Maintaining calorie intake is particularly important in a rapidly growing puppy. If mouth opening becomes severely restricted, assisted feeding or more intensive nutritional support may be required. Secondary problems such as dehydration are treated promptly.
Surgery is not routinely used to remove the proliferative bone because the disease can involve broad areas of the jaw and skull and may continue producing new bone while the puppy is still growing. Procedures may occasionally be considered for a specific mechanical complication, but conservative management is usually preferred while waiting for the active phase to subside.
Many dogs improve substantially once skeletal growth is complete, and some excess bone remodels over time. Severe cases have a more guarded outlook if pain cannot be controlled or the puppy cannot eat adequately. Regular weight checks and reassessment of jaw movement help guide decisions. Humane euthanasia is rarely necessary but may be considered when severe disease prevents acceptable nutrition and comfort despite intensive supportive care.
Breeds or species affected
Boston terrier
Open dog breed description, care requirements and conditions
Boxer
Open dog breed description, care requirements and conditions
British Bulldog
Open dog breed description, care requirements and conditions
Bull mastiff
Open dog breed description, care requirements and conditions
Bull terrier
Open dog breed description, care requirements and conditions
Cairn terrier
Open dog breed description, care requirements and conditions
Catahoula leopard dog
Open dog breed description, care requirements and conditions
Dobermann
Open dog breed description, care requirements and conditions
German Wirehaired Pointer
Open dog breed description, care requirements and conditions
Golden retriever
Open dog breed description, care requirements and conditions
Great Dane
Open dog breed description, care requirements and conditions
Pyrenean Mountain Dog
Open dog breed description, care requirements and conditions
Irish setter
Open dog breed description, care requirements and conditions
Kerry blue terrier
Open dog breed description, care requirements and conditions
Labrador retriever
Open dog breed description, care requirements and conditions
Scottish terrier
Open dog breed description, care requirements and conditions
Shetland sheepdog
Open dog breed description, care requirements and conditions
Staffordshire bull terrier
Open dog breed description, care requirements and conditions
Weimaraner
Open dog breed description, care requirements and conditions
West Highland white terrier
Open dog breed description, care requirements and conditions