What Exactly Is A Trigger Point

Travell’s etiological definition of a myofascial trigger point is a cluster of electrically active loci, each of which is associated with a contraction knot and a dysfunctional motor endplate in skeletal muscle.

The clinical definition describes a hyper-irritable spot in skeletal muscle that is associated with a hypersensitive palpable nodule in a taut band. The spot is painful on compression and gives rise to characteristic referred pain, referred tenderness, motor dysfunction and autonomic phenomena.

The trigger points are areas of taught, hypercontracted bands, or nodules, within a muscle. They are tender to touch, and have a predicted pain referral patterns. These hypercontracted nodules within the muscle are palpable.


Drs Janet Travell ,David Simons & Lois Simons(1999). Myofascial Pain and Dysfunction: The Trigger Point Manual (2 vol. set, 2nd Ed.). USA: Lippincott Williams & Williams

Referred Pain

Palpation of this spot within the trigger point provokes radiating, aching-type pain into localized reference zones. Research suggests that myofascial pain and dysfunction with characteristic trigger points and taut-bands are a spinal reflex disorder caused by a reverberating circuit of sustained neural activity in a specific spinal cord segment. The treatment of myofascial pain disorders requires that symptomatic trigger points and muscles are identified as primary or ancillary pain generators.

Causes

If a muscle fiber is damaged, the sarcoplasmic reticulum may be unable to take back the cytoplasmic calcium into storage. The contractile protein molecules cannot decouple because the high concentration cytoplasmic calcium. This results in persistent contraction for the muscle fiber, even without any further impulse from the motor nerve. If this energy consuming process continues, sensitive muscle bands are formed.

Mechanical, thermal and chemical treatments, which neurophysiologically, or physically, denervate the neural loop of the trigger point, can result in reduced pain and temporary resolution of muscular over contraction. Most experts believe that appropriate treatment should be directed at the trigger point to restore normal muscle length and proper biomechanical orientation of myofascial elements, followed by treatment that includes strengthening and stretching of the affected muscle.