Atlantoaxial instability is abnormal movement between the atlas, the first cervical vertebra, and the axis, the second. It may result from ligament injury, trauma, inflammatory disease or a congenital abnormality and carries a variable risk of cervical spinal cord compression.
An articulation requiring protection
The C1–C2 joint provides a large share of head rotation. Stability depends particularly on the transverse ligament and bony anatomy. Certain fractures, rheumatoid arthritis and congenital disorders can compromise it. An imaging abnormality must be interpreted alongside the underlying condition and neurological findings.
Manifestations and emergency signs
Upper-neck pain, a tilted head, clumsiness, altered gait or weakness may raise concern. Significant neck pain after trauma needs assessment without moving the neck to test it. New weakness, breathing difficulty or loss of bladder control requires immediate emergency assistance. Do not attempt to reposition the neck.
Specialist diagnosis
Examination and imaging look for displacement, bone or ligament injury and compression. CT and MRI provide complementary information. Movement radiographs must only be performed when specifically indicated and considered safe; they are not a self-testing exercise. The approach differs between an acute injury and surveillance of a known condition.
Treatment and follow-up
Management depends on the cause, stability and neurological effects. Immobilization, treatment of inflammatory disease or surgical stabilization may be required. Activities and sports are individualized. Screening protocols differ between underlying disorders and cannot be reduced to obtaining one normal radiograph without considering symptoms or subsequent changes.
Role of TAGMED care
Suspected instability requires medical assessment before cervical treatment. TAGMED must not offer forceful manipulation or traction to correct this problem. Following confirmed stabilization, functional support can be discussed while strictly following the specialist team’s recommendations for movement, loading and activity.
Frequently asked questions
Is trauma always the cause?
No. Inflammatory or congenital conditions can also be responsible.
Does neck pain establish instability?
No. Many causes of neck pain do not involve abnormal stability.
Can someone test rotation themselves?
Not when instability is suspected.
Does a normal radiograph remove all future risk?
No. Symptoms and the underlying condition still matter.
Is surgery inevitable?
No. Anatomy, cause and the risk to nervous tissue guide the decision.
Conceptual diagram: do not provoke movement to test suspected instability yourself.
Medical references
- World Federation of Neurosurgical Societies. Upper Cervical Spine Trauma: WFNS Spine Committee Recommendations.
- American Academy of Pediatrics. Health Supervision for Children and Adolescents With Down Syndrome.
- World Federation of Neurosurgical Societies. Syndromic Atlanto-axial Instability: WFNS Consensus on Screening and Surveillance, Sports Clearance, and Treatment Options.
References document the topic; their inclusion does not imply endorsement of TAGMED services by those organizations.
Educational information from The Spine Page. This entry does not replace an individual assessment. Documentary version: October 12, 2026. Sylvain Desforges, B.Sc., D.O., N.D., osteopath and naturopath.
TAGMED clinic contact details
These contact details do not replace emergency care. For severe or rapidly progressive symptoms, go to an emergency department; call 911 when needed.
Clinique TAGMED — Terrebonne
1150, rue Lévis, Suite 200
Terrebonne (Québec) J6W 5S6
450‑704‑4447
Clinique TAGMED — Montréal
1140, avenue Beaumont
Mont-Royal (Québec) H3P 3E5
1‑877‑672‑9060