Craniomandibular Osteopathy in Dogs

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Last updated on
3 min read

Key takeaways

Craniomandibular Osteopathy (CMO) describes the growth of areas of new bone around the head and jaws.

  • CMO is a rare condition of no known origin seen in young, growing dogs, usually between 3-7 months old
  • A genetic mutation is highly associated with CMO in some breeds, but not all
  • Dogs with CMO present with reluctance to eat, difficulty chewing, and pain when opening the mouth
  • Abnormal bony changes are often found on the bottom of the jaw and there are sometimes changes in the facial appearance
  • Investigation of CMO involves physical examination and diagnostic imaging
  • CMO is a self-limiting disease which normally resolves spontaneously
  • Treatment includes supportive feeding, fluid therapy, and medication such as pain relief and antiinflammatories
  • Prognosis is usually good except in rare cases where the joint of the jaw bones becomes fused, which usually results in euthanasia
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A closer look: Craniomandibular Osteopathy in Dogs

CMO is a severe, distressing condition in puppies. While most puppies have a favorable outcome, CMO is a painful condition that interferes with the ability to eat and requires high doses of pain relief until the condition resolves. Cases where the jaw joints fuse carry a poor prognosis and patients are often euthanized.

Suspected cases of CMO require prompt veterinary attention.

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Risk factors

When CMO interferes with the ability to eat over time, poor body condition, weight loss, and lethargy may occur.

CMO is found most commonly around the head. In some cases the long bones of the legs are also affected, resulting in lameness.

CMO is rare, but occurs more often in West Highland whites and other terriers. Symptoms usually arise in puppies between one to three months of age, and resolve by the time the puppy is a year old.

Possible causes

The underlying trigger for CMO is not fully understood but the disease is seen more commonly in certain breeds. A genetic abnormality has been found in some terrier breeds, but the mechanism in other breeds is unknown.

The symptoms result from the non-cancerous, non-inflammatory proliferation of new bone growth in characteristic locations on the skull and jaw.

Main symptoms

Testing and diagnosis

Further investigation involves:

  • Physical examination
  • Diagnostic imaging
  • Bone biopsy

Steps to Recovery

Treatment options include

  • Assisted feeding where necessary
  • Fluid therapy
  • Pain relief medication
  • Anti Inflammatories

CMO is self-limiting and resolves spontaneously. Most cases have a good prognosis. Cases where the joints of the jaw fuse together (ankylosis of the temporomandibular joint) do not resolve and the prognosis is usually poor. Euthanasia is usually appropriate in these cases.


CMO is not contagious but has an inherited component. Affected dogs should not be bred.

Is Craniomandibular Osteopathy in Dogs common?

CMO is rare in dogs.

Typical Treatment

  • Assisted feeding where necessary
  • Fluid therapy
  • Pain relief medication
  • Anti Inflammatories


Kyle Braund BVSc MVSc PhD FRCVS DipACVIM - Writing for Vetlexicon

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