The Trigeminocervical Nucleus and Evidence for Manual Therapy

The upper three cervical nerves converge with the trigeminal system in the trigeminocervical nucleus (TCN), so input from either side can be felt as head or neck pain. Quantitative sensory testing links headache to TCN sensitization, and Bogduk's work shows that only levels from C2-3 upward refer pain to the head. Toby compares the TCN to a bucket: once it is full, a small extra input from the neck or trigeminal system triggers a headache. Dean Watson reproduced headache with sustained upper cervical pressure that eased with repetition and changed the blink reflex, unlike painful pressure at the elbow. Later studies with Mehdi Jafari showed changes in the blink reflex and brainstem auditory evoked potentials after four sessions of manual therapy compared with sham. In René Castien's trial, nine sessions of manual therapy and exercise reduced chronic tension-type headache more than GP care, with effects at six months. Reviews support manual therapy for tension-type and cervicogenic headache, while evidence for migraine is weaker. Cervicogenic and tension-type headache need a bottom-up approach, migraine more often a top-down one.