II. Epidemiology
- Incidence: 15% of Down Syndrome age <21 years old
- Congenital atlantoaxial defects also seen in Congenital Dwarfism, odontoid hypoplasia
III. Symptoms suggestive of Atlantoaxial Instability
IV. Signs suggestive of Atlantoaxial Instability
- Neck Pain
- Torticollis
- Motor weakness in upper or lower extremities
- Increased Deep Tendon Reflexes
- Babinski response
- Clonus
V. Radiology: C-Spine XRay
- Indications
- Routine screening at age 5-6 no longer recommended
- Xray indicated for Signs or symptoms above
- Screen prior to Contact Sport participation
- Views
- Neutral
- Flexion
- Extension
- Interpretation
- Measure C1-C2 space
- Posterior segment of anterior arch of C1
- Anterior segment of odontoid process of C2
- Distance should be no more than 5 mm
- Measure C1-C2 space
VI. Prognosis
- Precludes Contact Sport participation if present