Cerebrovascular accidents are an uncommon, but well documented, complication of cervical spine manipulation. This paper reviews vertebral artery gross morphology and pathoanatomy as they relate to possible mechanisms of injury to this vessel. Certain positions of the head and neck can lead to vertebral artery compromise and may ultimately lead to a cerebrovascular accident. The results obtained from a cadaver study on vertebral artery diameter at the site of the posterior arch of atlas are also presented.