TMJ and Trigger Points

Myofascial Pain Syndrome

The main innovation of Travell’s work was the introduction of the myofascial pain syndrome concept (myofascial referring to the combination of muscle and fascia). This is described as a focal hyperirritability in muscle that can strongly modulate central nervous system functions. Travell and followers distinguish this from fibromyalgia, which is characterized by widespread pain and tenderness and is described as a central augmentation of nociception giving rise to deep tissue tenderness that includes muscles. Studies estimate that in 75–95 percent of cases, myofascial pain is a primary cause of regional pain. Myofascial pain is associated with muscle tenderness that arises from trigger points, focal points of tenderness, a few millimeters in diameter, found at multiple sites in a muscle and the fascia of muscle tissue. Biopsy tests found that trigger points were hyperirritable and electrically active muscle spindles in general muscle tissue.

Qualities of trigger points

Trigger points have numerous qualities. They may be classified as potential, active/latent, key/satellites, and primary/secondary.

There are few more than 620 potential trigger points possible in human muscles. When they become active or latent, these trigger points show up in the same places in muscles in every person. This means that trigger point maps that are accurate for everyone can be made.

An active trigger point is one that actively refers pain either locally or in another location (most trigger points refer pain elsewhere in the body along nerve pathways). A latent trigger point is one that exists and does not yet refer pain actively but may do so when pressure or strain is applied to the myoskeletal structure containing the trigger point. Latent trigger points can influence muscle activation patterns, which can result in poorer muscle coordination and balance. Active and latent trigger points are also known as “Yipe” points, for obvious reasons.

A key trigger point is one that has a pain referral pattern along a nerve pathway that activates or creates a latent trigger point on the pathway. A satellite trigger point is one that is activated by a key trigger point. Successfully treating the key trigger point will often resolve the satellite, either converting it from being active to latent or completely treating it.

In contrast, a primary trigger point in many cases will biomechanically activate a secondary trigger point in another structure. Treating the primary trigger point does not treat the secondary trigger point.

Potential causes of trigger points

Activation of trigger points may be caused by several factors, including acute or chronic muscle overload, activation by other trigger points (key/satellite, primary/secondary), disease, psychological distress (via systemic inflammation), homeostatic imbalances, direct trauma to the region, accident trauma (such as a car accident which stresses many muscles and causes instant trigger points) radiculopathy, infections, and health issues such as smoking.

Trigger points form only in muscles. They form as a local contraction in a small number of muscle fibers in a larger muscle or muscle bundle. These, in turn, can pull on tendons and ligaments associated with the muscle and can cause pain deep within a joint where there are no muscles. When muscle fibers contract, they use biochemical energy. Depleting these biochemicals leads to the accumulation of fatigue toxins such as lactic acid. The tightened muscle fibers constrict capillaries and prevent them from carrying off the fatigue toxins to the body’s recycling system (liver and kidneys). The buildup of these toxins in a muscle bundle or muscle feels like a tight muscle—a slippery elongate bundle.

When trigger points are present in muscles, there is often pain and weakness in the associated structures. These pain patterns in muscles follow specific nerve pathways and have been readily mapped to allow for the identification of the causative pain factor. Many trigger points have pain patterns that overlap, and some create reciprocal cyclic relationships that need to be treated extensively to remove them.

Click here for a quick video that explains TMJ Trigger Points.

Source Wikipedia