Headache is a pain in the head and neck region that may be either a disorder in its own right or a symptom of an underlying medical condition or disease. The medical term for headache is cephalalgia. Headaches are one of the most common and universal human ailments, described in the Bible as well as in medical writings from ancient Egypt, Babylonia, Greece, Rome, India, and China. Severe chronic headaches were once treated by the oldest known surgical procedure, known as trepanning or trephining, in which the surgeon drilled a hole as large as 1–2 in diameter in the patient's skull without benefit of anesthesia. Evidence of trepanning has been found in skulls from Cro-Magnon people that are about 40,000 years old.
Contemporary doctors divide headaches into two large categories, primary and secondary, according to guidelines established by the International Headache Society (IHS) in 1988 and revised for republication in 2004. Primary headaches are those that are not caused by an underlying medical condition. There are three types of primary headaches: migraine, cluster, and tension headaches. More than 90% of all headaches are primary headaches. Secondary headaches are caused by disease or medical condition; they account for fewer than 10% of all headaches.
Rebecca J. Frey PhD, The Gale Group Inc., Gale, Detroit,