While the Flexion Rotation Test (FRT) primarily measures rotation at the C1-2 segment, the author has never attributed any limitation detected by the test to an inherent problem within the C1-2 segment itself. Instead, the belief has been that the FRT can serve as an indicator of upper cervical dysfunction.
It’s important to note that asymptomatic rotation of C2 is common and is present in various benign headache conditions. Moreover, based on the specific presentation of head pain, the direction of C2 rotation can be predicted with approximately 90% accuracy (anecdotally).
The primary muscle responsible for C2 rotation is the inferior obliquus capitis, which often reacts to issues at the C2-3 and potentially at the C0-C1 segment. Therefore, it is both unsurprising and encouraging to read the results of (click on link to access full article):
Rodríguez-Sanz J, et al. Effects of the Manual Therapy Approach of Segments C0-1 and C2-3 in the Flexion-Rotation Test in Patients with Chronic Neck Pain: A Randomized Controlled Trial Int J Environ Res Public Health. 2021 Jan 17;18(2):753. doi: 10.3390/ijerph18020753.
