The pain of Fibromyalgia (FM) is present in the soft tissues throughout the body. Pain and stiffness concentrate in spots such as the neck and lower back. The tender spots don't seem to be inflamed, nor do they display the typical signs of discomfort, such as heat, redness, or swelling. Most tests show nothing out of the ordinary in the anatomy of people with FM.

The FM tender points consist of nine bilateral sites adding up to 18 in total. The picture below and to your right shows the 18 tender point sites that have been identified by the American College of Rheumatology (ACR). According to the ACR criteria, FM is present when a patient suffers widespread pain for at least three months and feels pain in 11 or more of the 18 pressure point sites.

Doctors measure these tender points in one of two ways:

• By pressing the site with a finger or
• By using a slightly higher-tech method called dolorimetry

In the dolorimetry method, the examiner presses a rubber endplate, attached to a spring-loaded force gauge, into the tender point site with increasing force. Patients are then asked to say when they stop feeling pressure and start feeling pain.

In the picture below each set of tender points are color coded. Each color identifies a specific tender point location.