More than 90% of headaches can be classified as primary headaches which include; tension-type, migraine, cervico-genic, and cluster headaches and are not caused by other underlying conditions. Primary headaches are cause by an imbalance in the neck musculature and can present with a different pain pattern from person to person.

A report released in 2001 by researchers at the Duke University Evidence-Based Practice Center in Durham, NC, found that spinal manipulation (chiropractic adjustment) resulted in almost immediate improvement for those headaches that originate in the neck, and had significantly fewer side effects and longer-lasting relief of tension-type headache than a commonly prescribed medication. Scientific evidence supports chiropractic adjustments as safe, effective and an appropriate choice for patients with many common forms of neck pain and headaches.