Myofascial pain syndrome, a very common condition, is a collection of signs and symptoms in a particular area of the body that indicate muscle trauma.1 Myofascial pain syndrome is not the same as a back muscle spasm, although it does involve spasm, as described below.
Myofascial Spasm Pain Cycle
Left untreated, myofascial pain is often experienced as a recurring cycle of spasm, pain, and spasm again.2 The exact cause of the spasm is not known. It may be related to excessive leakage of acetylcholine (a biochemical neurotransmitter) causing a sustained muscle contraction.3 Another theory is that repetitive small trauma to the muscle helps to create a “trigger point."4
Myofascial pain syndrome is characterized by active trigger points in muscles.5 Active trigger points can be felt not only where they are located, but also as pain referred to other areas. Each muscle has a particular referral pattern; in other words, pain that goes from a trigger point in a specific muscle to another place in the body will show up pretty much the same way in every person who has trigger points in that particular muscle.5 Medical providers and massage therapists trained in this area can identify trigger points by their pain pattern.
With myofascial pain syndrome, muscles become tense and taut, and joint range of motion decreases.1
How Myofascial Spasms and Pain Come About
Myofascial pain is often caused by long periods of time spent in poor postural alignment.6 Ideally, the fit of the bones is designed to keep body posture upright and moving smoothly, but when that is not occurring, muscles take over the job.
As an example, when you sit at your computer all day long and your upper body begins to slump forward, to raise your head to see, you use your upper trapezius muscle.7 (The upper trapezius muscle is located on the top of your shoulders.) The trapezius muscle is now working at something it is not really supposed to do and is doing so continuously. There is little time for rest and relaxation. Instead, the continual contraction of the trapezius may cause microscopic injury to this muscle.8 This microtrauma may increase the trapezius muscle spasm, resulting in more microtrauma, and thus perpetuating the pain-spasm cycle.3
The normal, self-protective response of an injured muscle is to seize up, or spasm. But in this situation, the extra input of tension into the trapezius intensifies the situation. The constriction in the trapezius muscle reduces nourishing blood flow to the area, which in turn, causes pain.9 The pain then signals the cycle to begin again.
Unless this cycle is interrupted by treatment, it may continue, intensifying with each iteration. This spasm-microtrauma cycle may cause the muscle to develop trigger points and lead to chronic pain.