Cervicogenic headaches arise from problems originating in the structures of the neck. The nature and patterns of pain, as well as the factors that initiate a particular episode of cervicogenic headache, often overlap with other headache types. For this reason, cervicogenic headaches, though now widely recognized, were historically overlooked. Common cervicogenic headaches are caused by anything from an acute, severe injury, such as whiplash, to the repetitive microtrauma of improper working or sleeping posture. Because of their structural nature, these headaches are characteristically one-sided.
Nerve-Related Causes
Areas of the central nervous system where sensory nerves from different structures converge upon a central location can lead to confusion when the brain tries to locate the source of the pain message. This is a cause of cervicogenic headache involving the trigeminal nerve, which normally transmits sensation from the face and head, whereby sensory fibers carrying information from the upper cervical spine influence the nearby lower portion of the trigeminal nerve.
Pain referral patterns from the first three cervical nerves also frequently include areas of the head. These pain patterns have been mapped as to their characteristic location and quality. The suboccipital nerve arises from C1 and, when damaged or irritated, causes pain at the base of the skull. The second and third spinal nerves cause pain patterns at the sides and front of the head and around the eyes.
Muscular Causes
Trigger points are areas of increased tension and irritability within muscles that produce patterns of pain referral that are distinct from neurologic referred pain. Trigger-point-induced headaches are capable of producing dizziness, nausea, ringing in the ears, areas of numbness, sinus congestion, tearing of the eyes and other signs and symptoms that occur in other types of headaches, notably migraines. An important characteristic of trigger points is that their pain patterns can be elicited during non-symptomatic times and in between headache occurrences by applying pressure to them. Muscles of the neck that are frequently associated with cervicogenic headaches include the sternocleidomastoid, trapezius, semispinalis capitis, semispinalis cervicis and splenius capitis.
Acute and Chronic Causes
Whiplash, athletic mishaps and other sudden traumatic events that injure bone or soft tissue structures of the neck can lead to headaches by damaging or stressing those structures. Chronic postural strain from a variety of occupational activities, such as computer work, creates repetitive microtrauma that can lead to cervicogenic headache syndrome via trigger point formation, vascular constriction and nerve irritation. Poor sleeping posture can also contribute to the stresses that produce cervicogenic headaches. Underlying primary pathologies, including tumor, inflammatory conditions and structural malformations, should be investigated as causes of a chronic cervicogenic headache syndrome.
