What is a Myofascial Trigger Point and Its Relationship to Pain?

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Have you ever developed cramping in your hands and fingers from typing too much, or had pain in your calf muscles from wearing ill fitted shoes or overdoing? These are examples that could be the result of developing myofascial trigger points.

What Is a Myofascial Trigger Point?

A myofascial trigger point (TrP) is a self-sustaining irritable area in a taut/tight band of muscle fiber that is felt as a nodule or bump. The irritated spot causes shortening of the muscle involved interferes with movement causing pain and weakness.

Common Abbreviations

  • MTrP = myofascial trigger point
  • TrP = trigger point
  • TrPs = trigger points (plural)

Muscles develop TrPs because of injury, surgery, poor posture, repetitive motion, chronic tension, muscle strain, disease, or other aggravating factors. They can also cause changes in balance, nausea, vision, hearing, heart palpitations, bowel and gonad related difficulties, urinary difficulties, and many other autonomic disruptions. Trigger points can cause burning, or numbness and tingling if the TrP is entrapping a nerve. Circulation changes can occur if a TrP is located next to a blood vessel, which can cause skin temperature or color changes, and swelling can develop if the TrP is located next to a blood or lymph vessel. Regardless of their size or their location, they can wreak havoc.

A TrP has both a sensory and motor component demonstrated by tenderness, and a referred pain pattern. If they are active, we can see a local twitch response, spontaneous electrical activity (SEA) on a recording (resembling an EKG of the heart), and can locate them using ultrasound.

How to Locate a Trigger Point

Trigger points can occur anywhere there is skeletal muscle and they are easily felt unless they are behind bone, other larger muscles, or the muscle involved is too rigid. They radiate pain in a particular pattern consistant with their location.

When we are in pain, we tend to start rubbing around a painful area to see if we can make our pain better. Next time you do this, see if you feel that telltale knot or a muscle that feels like a banjo string or a golf ball. Press on the area to see if the pain radiates. If the muscle is tight, you may have to massage it before you can locate the trigger point (TrP). If you can’t feel it, don’t be discouraged. It takes practice and it could be buried.

Types of Trigger Points

Primary Trigger Point

A primary trigger point is the one that starts the ball rolling. As an example, a primary TrP develops in your neck because you sat at a computer for too long. As we sit, our head, which is quite heavy, starts to droop forward. This stretches the muscles at the back of the neck and if it goes on for too long, the muscle fibers will knot up from being overloaded with more work than it can handle.

Secondary (Compensatory) Trigger Point

OK, so you ignored that tight muscle that developed, so what’s next? Left untreated, other muscles become temporary workers. Using the same example, your neck starts to hurt on the front side, in a muscle on the opposite side of your neck, or in a muscle in the same group just in a different spot. These compensatory TrPs are called secondary trigger points.

Pain may shift as secondary TrPs are revealed and treated. It’s not always easy to define a primary from a secondary trigger point unless you have the knowledge, but eventually with the help of a trained professional and some self-treatment, you will unravel them.

Satellite Trigger Point

A satellite trigger point is a type of secondary TrP that develops in the referral zone of a primary trigger point.

Trigger Point Stages

Active Trigger Point

An active TrP can be primary or secondary. The key characteristic is that they cause pain at rest. These TrPs cause you to start rubbing the area, because it is always tender, and the muscle fiber is shortened and weak. When you push on the knot or tight muscle, it causes referred pain, and you may see or feel a local twitch response.

An active TrP can also cause the referral zone to become tender, regardless if it is primary or secondary. Remember this, because not everyone understands. The specific locations of TrPs, such as in the illustration, cause these specific patterns. Trigger points located in the same muscle in different locations refer pain to different areas.

Latent Trigger Point

This type of TrP, which can also be primary or secondary, is only painful when pressure is applied. However, like all TrPs, they restrict muscle movement affecting joints in the spine and extremities causing stiffness and weakness and can cause autonomic effects. I call them "latent in waiting" because symptoms can persist for years after apparent recovery. Unless restricted motion or weakness causes you to start rubbing around to find the source, a latent TrP may go unnoticed.

The primary difference between an active TrP and a latent TrP is that an active TrP causes pain at rest and a latent TrP does not. All the other things they share in common.

End Comments

Myofascial TrPs are implicated as a source to, or a contributing factor in, chronic pain, and it is thought to be the peripheral pain generator in fibromyalgia.  Trigger points can mimic, or be the cause of, sciatica, pelvic floor pain, costochondritis, vulvodynia, testicular pain, TMJ/TMD, restless leg syndrome, headaches, and much more. Amoung other things, they can cause painful intercourse, impotence, bladder and bowel difficulties, and affect many things as previously noted. They are NOT to be taken lightly. Early treatment by a qualified physician, chiropractor, or therapist may prevent development of myofascial pain syndrome. Stay tuned, information on myofascial pain syndrome and treatments are coming.