Concussion Management For The Physical Therapist Practice Test

The key idea is isolating the motion that the atlantoaxial joint (C1–C2) allows most prominently: rotation. To specifically assess this joint, you use the cervical flexion-rotation test. By passively flexing the upper cervical spine first, you "unlock" or lock out motion at the occipito-atlantal joint, so subsequent rotation mainly occurs at the AA joint. If rotation is limited or reproduces concordant symptoms, this points to dysfunction at the C1–C2 level. The occipito-atlantal joint primarily handles nodding (flexion/extension) and some side bending, so its mobility isn’t what the cervical flexion-rotation test targets. A test of C2–C3 mobility, on the other hand, examines a lower cervical segment, not the upper cervical region where AA motion occurs. So, using the cervical flexion-rotation test is the best way to evaluate the atlantoaxial joint because it isolates rotation at that specific joint after enabling a clear assessment by reducing OA involvement.