Pelvic Muscle Trigger Points: The Myofascial Connection
Robin Christenson, MPT

To recap the article, “The Role of Pelvic Hypertonicity in the Pain Spasm Cycle” initial pelvic dysfunction such as interstitial cystitis, vulvodynia, low back pain, sciatica or surgical scars can cause inflammation, dysfunction and pain leading to pelvic muscle spasms or hypertonicity. As you have more than twenty muscles that connect to your pelvis, spasms in the muscles can lead to myofascial trigger points.

Myofascial Trigger Points

Myo- means muscle, and fascia is the connective tissue webbing around and within the muscle. Myofascial trigger points are irritable, tender “knots” or nodules within a muscle causing the muscle to become tense. Prolonged overload or irritability of a muscle can result in trigger points.

Figure 1. Understanding Myofascial Trigger Points
Just as a car runs on gas, your muscles are fueled by calcium. Under normal circumstances, when you drive you push the gas pedal just enough to accelerate the car. If you were to drive the car while impaired, a sudden, hard pressure on the gas pedal would send the car lunging forward.
In the junction where the nerve communicates with a muscle (your foot on the pedal) a nerve will release acetylcholine (the pressure of your foot on the pedal) which causes a release of calcium (the gas) and tells the muscle to contract. If the nerve is impaired or irritated it may release excessive amounts of acetylcholine (too heavy on the gas pedal), causing large releases of calcium (the fuel for the muscle), resulting in a sudden, hard muscle contraction.
If you make a sudden tight fist, what happens? Your hand starts to turn white. This is because a hard muscle contraction chokes off local circulation causing ischemia. Ischemia, or lack of blood flow, depletes the muscle of energy. Without energy, the muscle’s calcium “pump” is not able to remove excess calcium. Excess calcium continues to give the muscle the “gas” to contract and a sustained spasm within the muscle fiber results.

FYI: Trigger points are not caused by having “too much calcium” in the body. In fact, low levels of potassium and calcium can actually perpetuate myofascial trigger points.

Referred Pain from a Myofascial Trigger Point

Myofascial trigger points have been shown to refer pain to other regions of the body. When a trigger point is active and painful, a chronic pain signal is sent through the C-fibers (slow acting pain nerve fibers) of a nerve to the spinal cord and then up to the centers of the brain that register pain. Due to the close proximity of the nerve fibers when entering the dorsal horn (pain area) of the spinal cord, nerves from surrounding tissues may “cross talk”, projecting sensations of pain to areas other than the exact location of the trigger point. For example, trigger points in the low back can refer pain into the buttocks or hip. As the brain senses pain in the surrounding muscles, these muscles can intern become agitated leading to more trigger points.