Kimmerle Anomaly, Vertebral Artery Syndrome and the Jaw

Many people discover a Kimmerle anomaly incidentally on X-rays, and there are many descriptions online of what it is. This article brings together less common opinions from world-level specialists who treat temporomandibular-joint dysfunction and have repeatedly encountered such cases: the Italian craniodont Giuseppe Stefanelli, the Indian researcher Parita K. Chitroda and the American TMJ specialist Jeffrey Brown. Their practice shows that the problem can be addressed by changing jaw position.

The “little posterior bridge”

In Latin the Kimmerle anomaly is called ponticulus posticus, meaning “little posterior bridge”. The term denotes a pathological change in the atlas, the first cervical vertebra, in which an additional bony arch appears as a semicircle and compresses the vertebral artery as it enters the cranial cavity. Formation of the bony ring passes through four stages before it becomes complete; these four stages are shown in the image above.

The causes of the Kimmerle anomaly are not reliably known. Four hypotheses are proposed: congenital pathology; post-traumatic change; incorrect posture and body position; or development of a compensatory mechanism intended to protect the vertebral artery. In Professor Stefanelli’s view, the last hypothesis is most likely, because postural deformities affect the first cervical vertebra and determine the degree of compression of the vertebral artery itself through muscular compensations in the body structure, including the neck.

Hundreds of online sources describe the consequences, but the main symptoms include headaches and migraines, ear pain, ophthalmological problems, dizziness and unsteadiness, loss of voice, mental disorders, insomnia and memory disorders. Many of these symptoms appear with neck movement, especially turning the neck.

Kimmerle anomaly and the jaw

Many studies worldwide have examined the connection of the Kimmerle anomaly with other body systems and associated illnesses. In paediatric departments in Newcastle and Sheffield in the United Kingdom in 2001, an association was identified between ponticulus posticus and cerebral stroke occurring against the background of neck movements. Literature also connects the anomaly with muscle tension and migraine.

One particularly interesting study found the anomaly in images of 858 patients who had undergone orthodontic treatment with braces. A complete bony ring was found in 4.3% of participants, with a higher prevalence in males, 5.33%, than in females, 3.76%. More interesting still is a study at Sapienza University of Rome, which examined cranial deformations and cervical-vertebral changes in patients with retained palatal canines, where a tooth is fully formed in the jaw but does not erupt, or erupts only partly. Thirty-eight patients aged fourteen to twenty-eight were examined. The anomalies concerned changes around the sella turcica, where the pituitary gland is located, and the presence of a Kimmerle anomaly on the atlas. The conclusion was that such anomalies occurred more often in patients with unerupted or crowded canines than in a control group.

Without going too deeply into technical language, one reason for unerupted, partly erupted and crowded teeth is a mismatch between teeth and the space available for them in the dental arch. We discussed this in the archive materials on proper tongue position and on the mechanism of TMJ dysfunction in pictures. If a child has insufficient or no breastfeeding, and later eats too little hard food, the oral apparatus does not develop enough and the tongue takes an incorrect relaxed position on the lower teeth. Yet this strongest muscle of the body, when correctly positioned on the palate, pushes the central bone of the face, the maxilla or upper jaw, forwards and upwards, forming a wide upper dental arch with sufficient space for every tooth.

With the tongue incorrectly placed on the lower teeth, the upper dental arch takes a V shape instead of a U shape, to which the lower jaw must adapt, with crowding arising there too. How can all this influence formation of the bony ring on the atlas? Professor Stefanelli’s research group found that Kimmerle anomaly formation was more frequent in young patients with Class II occlusion, the so-called posterior bite with the lower jaw shifted backwards, and in adult patients with TMJ dysfunction and decreased vertical space between atlas and skull. In both cases the atlanto-occipital distance decreases, and ponticulus posticus develops as a protective mechanism for the vertebral artery.

Once more about braces

The image above shows scans of four patients who underwent treatment with braces. All of them have a displacement of the first vertebra, the atlas; narrowed dental arches; Kimmerle anomaly; and the so-called “straight neck” or cervical kyphosis. This is another “pleasant bonus” to the already described consequences of braces that deform human body structure. Would formation of Kimmerle anomaly in these cases be a mere coincidence?

The absence of evidence for this anomaly in orthodontics also arises because conventional orthodontists do not assess the cervical spine on their images. On the contrary, the frequently used radiographic format is limited to the skull and excludes the cervical spine. Professor Stefanelli considers this a very serious omission, not only because it prevents evidence of vertebral anomalies from being obtained, but above all because cranio-cervical relationships matter in diagnosing and treating malocclusion.

Changing jaw position and the vertebral artery

Professor Stefanelli modestly says little about results obtained through craniodontic treatment, but he was among the first in the world to document vertebral-artery decompression at the end of treatment: moving the upper and lower jaw position and removing cranial deformities using an ALF appliance. Many similar results appear in his book Craniodonzia: Il sistema ALF. Its treatment mechanism is, honestly, for professionals well versed in cranial biomechanics. For a lay reader, the American craniodont Jeffrey Brown summarised the essence well:

“I work with many chiropractors, and they understand that there should be no clicking, twisting or crunching. When I show them X-rays like this, they understand. It all depends on whom you work with. Regarding dizziness, I would advise ALF treatment in these cases. The intraoral appliance acts like an expander for the whole skull, unlocking and relieving tension from the cranial bones. Most of my new patients come with dizziness and ringing in the ears, and in many cases these symptoms pass with time.”

Looking at the work of craniodonts, one may notice that besides unlocking the cranial bones, they change the angle of the skull relative to the jaw, increase the distance between atlas and occipital bone, and return the head’s axis to a vertical position. Perhaps this explains the reported resolution of symptoms in patients with Kimmerle anomaly: the organism no longer needs compensatory mechanisms to protect the vertebral artery from compression by surrounding structures.

In this connection it is impossible not to note the similar effect on the angle between skull and neck reported for the Italian Starecta method. Patients using the method also report disappearance of the symptoms described above, although, to be fair, no studies of patients specifically with Kimmerle anomaly were carried out in that case. This gives serious reason to question operations on the atlas’s bony ring, though thoughtful neurosurgeons themselves often discourage their patients from them.

Perhaps the way forward for people with Kimmerle anomaly lies precisely in bringing the bony structures of skull and neck into a balanced position. As noted above, the organism is then freed from the need to compensate a biomechanically balanced structure.

Read the archive articles on vertebral-artery syndrome and posture, and on biomechanical treatment of dystonia.