Pain usually generated when peripheral nociceptors are stimulated in response to tissue injury, visceral distension, or other factors.In such situations, pain perception is a normal physiologic response mediated by a healthy nervous system.
Pain can also result when pain-producing pathways of the peripheral or central nervous system (CNS) are damaged or activated inappropriately.
Headache may originate from either or both mechanisms.
Relatively few cranial structures are pain-sensitive they are
- Scalp
- Middle meningeal artery
- Dural sinuses
- Falx cerebri
- Proximal segments of the large pial arteries.
- The ventricular ependymal
- Choroid plexus
- Pial veins
- Much of the brain parenchyma
