DEFINITIONS OF MYOFASCIAL TRIGGER POINTS (MTRP)
Myofascial pain: pain arising from muscles or related fascia.
Active trigger point: an active trigger point causes spontaneous pain at rest, with an increase in pain on contraction or stretching of the muscle involved. There is often a restriction of its range of motion. Pain on motion may cause "pseudo-muscle weaknesses due to reflex inhibition.
Latent trigger point: deferrers from an active MTrP in that the nociceptors have become activated and sensitized but not enough to cause spontaneous pain to develop. However, a latent trigger point may restrict range of movement and result in weakness of the muscle involved and refer pain on compression. It is therefore possible to find latent MTrP in asymptomatic individuals.
Primary trigger point: the MTrP(s) whose nociceptor activity in a muscle or muscle group of muscles is primarily responsible for the pain syndrome, (can be active or latent).
Secondary MTrP: these develop elsewhere within the initially affected muscle or muscles group or the synergists or antagonists muscle of the initially affected muscle due to the overload or weakness caused by the primary MTrP. Therefore the myofascial pain syndrome may spread to involve a large area or region of the body. This increases the possibility of sensitizing the nervous system, leading to chronicity. Together with difficulties in accurately diagnosing the problem, due to the pain pattern and also problems associated with treating the condition effectively, (can be active or latent).
Satellite MTrP: these are MTrPs that become active when the muscle in which they are present is situated in the referred pain pattern of another MTrP. Similar to secondary MTrP the myofascial pain syndrome will then spread to involve a large area or region of the body increasing the possibility of sensitizing the nervous system, leading to chronicity. Together with difficulties in accurately diagnosing the problem due to the pain pattern and also problems associated with treating the condition effectively .
Ligamentous MTrPs: are found in lax, stretched ligaments as a result of aging, trauma and/or poor posture, particularly those ligaments involved in the support of the axial (vertebral column and pelvis) or appendicular (upper or lower extremities) skeleton. These MTrPs are extremely sensitive to further stretching and may be fired by prolonged maintaining of a stressful position or sudden movements to an extreme range. They are usually associated with weak, tight muscles. Periosteal MTrPs: are found on the surface of bone usually at the site of ligament or tendon attachment and related to tension on that area from a stretched ligament or tendon.