Trigger points are tight nodules located in skeletal muscles that when touched or pressured, produce tenderness, twitching and jumping. These responses are due to what the doctors call 'hyperirritability' of the trigger point. Trigger points cause a condition known as myofascial pain syndrome. The trigger points produce pain locally (right where they are) as well as often referring pain to other areas. Very often the muscles most affected with trigger points are the muscles of posture
Former U.S. President John F. Kennedy suffered from trigger points.
Alvarex, David, D.O, and Rockwell, Pamela, D.O., Trigger Points: Diagnosis and Management
. American Family Physicain. February 15, 2002. Retrieved: June 26, 2006.