ABSTRACT
Part A: Headache Anatomy • Headache, or cephalgia, is defined as pain in various parts o f the head, not confined to
the area o f distribution o f any nerve. • Headache is caused by distention, traction, displacement, inflammation, vascular spasm,
dilation, or compression o f the pain-sensitive structures in the head and neck. The pain-sensitive structures o f the supratentorial space refer pain via the trigeminal nerve, which innervates the anterior scalp and face. Pain-sensitive structures in the infratentorial space refer pain via cranial nerves IX, and X , and the second and third cervical nerves; thus, pain originating in the posterior fossa may be referred to the ear or throat, or the posterior area o f the head and neck.
