More than 47 million Americans have experienced a severe or debilitating headache in the past three months. Migraines alone affect 9% of the U.S. population and costs $1 billion a year in direct medical expenses.
There are 2 basic categories of headaches, primary and secondary. Primary headaches include vascular origin (cluster and migraine headaches) as well as muscular origin (tension-type headaches). Secondary headaches result from another source including inflammation or head and neck injuries.