Active Myofascial Trigger Point: A focus of hyperirritability in a muscle or its fascia that is symptomatic with respect to pain; it refers a pattern of pain at rest or on motion that is specific for the muscle.  An active trigger point is always tender, prevents full lengthening of the muscle, weakens the muscle, usually refers pain on direct compression, mediates a local twitch response when adequately stimulated, and often produces referred autonomic phenomena, generally in its pain reference zone.

Latent Trigger Point: A latent trigger point causes pain only when palpated but may cause restriction of movement, stiffness, and weakness of the affected muscle.  A latent TP may persist for years after apparent recovery from injury.  It predisposes the patient to acute attacks of pain from minor over-stretching, overuse or chilling which can reactivate it.

Both latent and active trigger points cause dysfunction.  Only active trigger points cause pain.

Common Misconceptions:

1. The pain from myofascial TP is pyschogenic, or purely “subjective” in origin.
2. Myofascial pain syndromes are self-limiting and will cure themselves.
3. That myofascial pain is not severe and need not be taken seriously.
4. That relief of pain by treatment of skeletal muscle trigger points rules out serious visceral disease.  TP therapy can temporarily relieve the pain of angina, myocardial infarction, and acute abdominal disease.