[Pathophysiology and clinical manifestation of cervicogenic headache].
Cervicogenic headache (CH) originates from disorders of the neck but is recognized as a referred pain in the head. Primary sensory afferents from the cervical roots C1-C3 converge with afferents from the occiput and trigeminal afferents on the same second-order neuron in the upper cervical spine. Consequently, the anatomical structures innervated by the cervical roots C1-C3 are potential sources of CH. In normal volunteers, the painful stimulation of different anatomical structures of the neck produced headache. In CH, particular structures have been selectively anesthetized in order to identify possible sources of pain. In summary, CH can origin from different muscles and ligaments of the neck, from intervertebral discs,and, particularly, from the atlantooccipital, atlantoaxial, and C2/C3 zygapophyseal joints. Diagnosis of CH should adhere strictly to the published diagnostic criteria to avoid misdiagnosis and confusion with primary headache disorders such as migraine and tension type headache.