Abstract

Understanding the anatomy and physiology of pain transmission system is important for the pain management. Some types of headaches, including migraine, are caused by activity in nociceptive afferents that innervate the cranial meninges, particularly the dura mater encephali and large intracerebral blood vessels. Pain can be evoked by electrical, mechanical, thermal, or chemical stimulation of dural blood vessels and sinuses or large intracerebral arteries. Importantly, the painful sensations were referred to the trigeminal dermatomes where typically headaches are localized. This article reviews the transmission of a nociceptive or pain impulse from the site of stimulus in the trigeminal nervous system to the central nervous system. The basic anatomic pathways of nociceptive transmission and of descending nociceptive modulations are described. The studies reviewed here likely apply more to acute pain than to chronic pain. It is now widely believed that stimulation of a primary afferent neuron in the peripheral nervous system results in activation of neurons in the dorsal horn of the spinal cord or the trigeminal brain stem nuclear complex, and then in transmission rostrally to the brain.