Frank Scali, DC, Eric S. Marsili, DC, Matthew E. Pontell, BSc BACKGROUND FROM DAN MURPHY, FromArticle Review 37-09: Anatomy and Physiology of HeadacheBiomedicine and Pharmacotherapy1995, Vol. 49, No. 10, 435-445N Bogduk It is known that the spinal dura matter is innervated with nociceptors that arisefrom the upper cervical nerve roots; this innervation allows the spinal dura to bethe generator of pain, primarily headache. The 4 suboccipital muscles are innervated by the posterior primary rami of the C1nerve root KEY POINTS FROM THIS ARTICLE: 1) Authors Scali and Marsili of this article are both chiropractors. 2) Chronic headaches in a significant amount of patients are of cervical origin. 3) These authors did meticulous investigations bilaterally of 3 suboccipitalmuscles on 13 human cadavers:Rectus Capitis Posterior Major (C2 spinous process to the occiput)Rectus Capitis Posterior Minor (posterior arch C1 to the occiput)Obliquus Capitis Inferior (C2 spinous process to the transverse process of C1) 4) Results: * In 86% (11/13), the fibers from the Rectus Capitis Posterior Major enteredthe space between C1 and C2 and firmly attached to the dura. * In 100% the fibers from the Rectus Capitis Posterior Minor entered the spacebetween the occiput and C1 and firmly attached to the dura. * In 86% (11/13) the fibers from the Obliquus Capitis Inferior entered thespace (atlantoaxial interspace) between C1 and C2 and firmly attached to the dura. 5) Manual traction of the Rectus Capitis Posterior Major caused dural movementfrom the spinal root level of C2 to the spinal root level of T1.