=====International Headache Society=====
The International [[Headache]] [[Society]] (IHS) is the world's leading membership organisation for those with a professional commitment to helping people affected by headache. 

As a charity, the purpose of IHS is to advance headache science, education, and management, and promote headache awareness worldwide.

====Journal====
Society's international journal is Cephalalgia. 

{{ ::international-headache-classification-iii-ichd-iii-2013-beta.pdf |International Headache Society Classification}}

[[Posttraumatic headache]] (PTH) is defined by the [[International Headache Society]] as: "a [[headache]] developing within seven days of the injury or after regaining consciousness"