Trigger points are discrete, focal, hyperirritable spots located in a taut band of skeletal muscle. They are painful on compression and can produce referred pain, referred tenderness, motor dysfunction, and autonomic phenomena. Trigger points can be classified as active or latent, depending on their clinical characteristics. An active trigger point causes pain at rest and is tender to palpation with a referred pain pattern that is similar to the patients pain complaint. This referred pain is felt not at the site of the trigger-point origin, but remote from it. A latent trigger point, on the other hand, does not cause spontaneous pain but may restrict movement or cause muscle weakness. Palpation of a hypersensitive bundle or nodule of muscle fiber of harder than normal consistency is the physical finding typically associated with a trigger point. Various modalities, such as the Spray and Stretch technique, ultrasonography, manipulative therapy, and injection, are used to inactivate trigger points. Trigger-point injection has been shown to be one of the most effective treatment modalities to inactivate trigger points and provide prompt relief of symptoms.