All physiotherapists and patients should be on the lookout for trigger points. Very painful and persistent muscle and joint pain will not resolve when an active trigger point is causing the pain. What is a trigger point?’ What makes a trigger point form?
Trigger points are small, hard, irritable nodules that form within a taut band of muscle tissue or its fascia. Trigger points can be difficult to locate because of their tiny size so it is easy for a manual therapist to glide over one without noticing it. Whenever pain is severe, persistent, and limits movement, the therapist should palpate the muscles carefully to discover possible trigger points.
Trigger points tend to form in shortened muscles that are lacking sufficient blood supply due to prolonged muscle tightness. They are likely to form in muscles that lack sufficient, proper exercise. They can also form in overworked muscles that are not properly stretched after vigorous activity, and in muscles or fascia that have been damaged by injury.
A trigger point prevents the muscle from fully lengthening and reduces its strength. Trigger points often refer pain to a distant muscle or other area of the body. For instance, when trigger points form in the sternocleidomastoid muscle of the neck, they can cause a neuralgia type pain in the cheek. They can also create pain that feels like a toothache or like a headache. They can also cause ringing in the ears or dizziness.
A healthy muscle does not have taut bands of muscle fibers or tender, hard nodules. There is no single conclusive study showing how a trigger point forms or what sustains the contracture of the involved muscle fibers. Various studies point toward a runaway metabolic process that occurs in the muscle, possibly when too much calcium is released from a damaged sarcomere. When the muscle is slowly and adequately stretched, the contracture (trigger point) will disappear and metabolic function will become normal.
Trigger points can cause pain symptoms similar to osteoarthritis, tendonitis, and peripheral neuropathy. The best way to prevent trigger points is to properly exercise and stretch muscles and to maintain good posture. Stress, anxiety, impaired sleep and nutritional deficiencies (vitamins B and C) can also contribute to the formation of trigger points.
Joan N. Sloss, EdD, LMT