The Craniocervical Flexors: Weak or Inhibited?

Muscle or ‘reflexive’ inhibition is crucial for manual therapists when addressing musculoskeletal dysfunction, particularly in the cervical spine. The brain’s ability to inhibit or ‘switch off’ muscles in response to perceived threats, whether painful or non-painful, is a well-documented neuromuscular phenomenon.

Muscle inhibition often indicates an underlying issue. Importantly, pain is not always the primary driver of muscle inhibition; altered proprioceptive input from the cervical spine can also significantly affect motor control.

Therefore, the deep neck or craniocervical flexors, which play a crucial role in cervical stability, may become inhibited if the brain detects dysfunction in the cervical spine. As a clinician, I often hear the comment, ‘My head feels too heavy for my neck.’ Passive mobilisation of the upper cervical spine, specifically C2-3, immediately resolves this feeling of weakness; they are not weak.

Interestingly, research has shown that interventions aimed at the cervical spine, without directly incorporating strength training, can significantly improve the function of the deep neck flexors.[1-3] These findings emphasise the need to address underlying issues rather than just focusing on muscle strengthening. Manual therapists can effectively ‘reset’ the brain’s perception of threat by addressing dysfunction and enhancing proprioceptive input. This alleviates the CNS’s protective inhibition, enabling the deep neck flexors to operate more efficiently.

References:

1. Pu, L.L., E. Miller, and R. Schenk, Utilizing directional preference in the management of cervicogenic headache: a case series. J Man Manip Ther, 2023. 31(6): p. 466-473.
2. Takasaki, H. and S. Herbowy, Immediate improvement in the cranio-cervical flexion test associated with MDT-based interventions: a case report. J Man Manip Ther, 2016. 24(5): p. 285-292.
3. Ghan, G.M. and V.S. Babu, Immediate Effect of Cervico-thoracic Mobilization on Deep Neck Flexors Strength in Individuals with Forward Head Posture: A Randomized Controlled Trial. J Man Manip Ther, 2021. 29(3): p. 147-157.