Trigger Point

Aka: Trigger Point

1. See Also
   1. Myofascial Pain Syndrome
   2. Trigger Point Locations
   3. Trigger Point Injection
2. Pathophysiology
   1. Trigger Points are central to Myofascial Pain Syndrome
   2. Trigger Points result in generalized muscle changes
      1. Tense skeletal muscle bands
      2. Muscle shortening
      3. Muscle Weakness
      4. Decreased muscle range of motion
   3. Trigger Point compression induces local and referred pain
      1. Compression of Trigger Point leads to local ischemia
      2. Ischemia leads to local inflammatory factor (prostaglandin, kinin) release
3. Preparation for exam
   1. Patient examined in relaxed position
4. Signs
   1. See Trigger Point Locations
   2. Taut, ropy bands, knots or Nodules of muscle fibers
      1. Surrounded by normal feeling muscle
   3. Muscle tenderness to palpation
      1. Local twitch response to palpation ("jump sign")
      2. Involuntary shortening of fibrous muscle band
   4. Trigger Points occur in predictable locations
      1. Trigger Points occur longitudinally along muscle axis
      2. Trigger Points are consistent from patient to patient
      3. Axial muscles (Posture) most commonly affected
   5. Pain Radiation
      1. Dull, aching, deep pain on Trigger Point palpation
      2. Predictable referred pain to distal reference zones
   6. Functional Disability
      1. Decreased range of motion
      2. Decreased flexibility on active and passive stretch
      3. Weakness of affected muscle
   7. Trigger Point pain types
      1. Active Trigger Point
         1. Ongoing, persistent pain
         2. May activate satellite or secondary Trigger Points
      2. Latent Trigger Point
         1. Asymptomatic until palpated
5. Differential Diagnosis: Tender Point (Fibromyalgia)
   1. Specific, symmetrical localized points in Fibromyalgia
   2. Tender Points are associated with total body pain
   3. Tender Points not associated with referred pain
6. Management
   1. See Myofascial Pain Syndrome
   2. See Trigger Point Injection
   3. See Stretch and Spray
   4. See Chronic Pain Management
7. Resources
   1. Trigger Point Physiology from Myopoint
      1. http://myopoint.com/network/physicians/myalgia.htm
8. References
   1. Alvarez (2002) Am Fam Physician 65(4): 653-60 [PubMed]
   2. Fomby (1997) Phys Sportsmed 25(2):67-75 [PubMed]