Os Odontoideum: Symptoms, Treatment


Os odontoideum is a rare condition that involves the second bone in the back. When the specific bone is detached from the rest of the bone, os odontoideum occurs. In the human body, there are all in all 33 bones or vertebrae in the spine. The spine in the neck is usually called the cervical spine, which is made up of two parts, C1 and C2. There is a joint between C1 and C2 called the dens, or odontoid process. This joint is key to allowing various movements such as turning, rotating and nodding the head. In the cases of os odontoideum, the top of the dens is separated from the rest C2. On the whole, the condition can be divided into two main types: orthotopic os odontoideum and dystopic os odontoideum.

At present, the prevalence of os odontoideum is not clear because investigation of the incidence of the condition is hard. Symptoms of the patients with os odontoideum vary a lot. But it is for sure that the condition is not common. According to researches and studies, the estimated frequency of os odontoideum is less than 2% of all cervical spine injury cases.


Right now, the exact cause of os odontoideum is still unknown. Researches on this topic are still ongoing. But experts in this area have gathered some clues.

Os odontoideum was firstly identified in 1886. Since then, a debate about whether os odontoideum is a congenital condition or an acquired condition has been raging on. According to the diagnosis data, some patients with os odontoideum may be born with the disease while others develop the condition due to trauma or injury in later life.

Moreover, studies have found that there are some diseases related to os odontoideum. People with down syndrome, Morquio syndrome and Multiple Epiphyseal Dysplasia tend to have a higher risk of developing os odontoideum.


People with os odontoideum may show no symptoms at all. In many cases, os odontoideum is detected coincidently when the patient receives other scanning tests for other reasons.

For a patient with os odontoideum, he or she may have the following symptoms:

  • Pain in the neck
  • Headaches
  • Torticollis
  • Weakness
  • Dizziness
  • Lack of coordination
  • Paralysis if it is severe


To determine whether a person has os odontoideum, the doctor often orders an X-ray test. In the procedure, invisible beams of electromagnetic radiation are used to produce detailed images of the bones. The test result can be helpful for the doctor to evaluate the stability of the joint.

Sometimes, the doctor may order other imaging tests such as CT and MRI scans to establish a diagnosis too.


Physical Therapy

For people with os odontoideum, if the joint appears to be stable, physical therapy may be considered to ease symptoms. The fundamental goal of physical therapy is to enhance the function of the spinal subsystems and reduce the stress on the spinal cord. By training to maintain the right posture and do proper amounts of exercises, people with os odontoideum can feel more comfortable.


If there are signs of instability, surgical treatment may become an option. When the condition starts to cause neurological symptoms such as weakness and vertigo, the doctor may recommend the patient to have surgery.

Spinal fusion and fixation are the main surgical approaches for that matter. In the surgical procedures, the doctor will use fine operational instruments and bone grafts to re-attach the dens to the C2. The doctor may choose the best treatment for each patient according to his or her specific situations.

Keywords: os odontoideum.

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* The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition.