There are 2 different theories as to how to assess the mobility of C1-C2. At Harris Health, I learned to maximally side bend the head, followed by opposite rotation. For example to assess C1-C2 rotation to the left, maximally side bend the head to the right, followed by maximal rotation to the left. The maximal side bend "locks out" the lower cervical vertebrae allowing for motion only at the C1-C2 junction.
The other method to assess C1-C2, which I learned in PT school at St. Louis University, is the flexion- rotation test. To perform this test, maximally flex the cervical spine followed by maximal rotation either left or right. Flexion is thought to lock out all vertebrae below allowing for rotation at C1-C2 only. The difficulty with the flexion-rotation test is maintaining flexion while maximally rotating the upper cervical spine. From my experience, there is a tendency to lose upper cervical flexion.
It is important to understand that different programs teach different methods of assessment. One method is not better than the next as long as there is sound reasoning behind your decision making.
Does anyone else assess C1-C2 differently or have preference with one method over the other? Let us know!
Thank you to the Harris Health Orthopedic Residency for letting me use images from their Cervicothoracic Module Workbook.