This is a link to a website that is owned and operated by a gentleman who experienced his first upper cervical chiropractic adjustment.  You will hear the explanation of his experience with upper cervical chiropractic and explanation from his doctor.  Dr. Scott Bales is an Upper Cervical Practitioner in Canada and the finest.  Enjoy the website. 

http://www.publicfreepress.com/Upper_Cervical.html