Trigger points are a common annoyance for many individuals, regardless of activity levels. Trigger points, also known as trigger sites or muscle knots, are described as “hyperirritable” spots in the muscle that have nodules in taut bands of the muscle fibers. These nodules produce pain, both locally and/or in a referred pattern.
Trigger points can be caused by a number of factors. Acute trauma or micro-trauma can lead to stress on muscle fibers and cause trigger points. Chronic musculoskeletal disorders often accompany trigger points as well. Activation of trigger points can be caused by: other trigger points (key/satellite, primary/secondary), disease, psychological distress, direct trauma to the region, accident trauma (such as a car accident which stresses many muscles and causes instant trigger points) and infections or preexisting health issues.
Compression of trigger points can create local tenderness and even a twitch response. The local twitch response however, is not the same thing as a muscle spasm because a spasm occurs throughout the entire muscle belly, whereas a local twitch response includes only a small twitch and no muscle contraction.
The different types of trigger points are: Active trigger points, ones that actively refer pain either locally or to another location. Latent trigger point is one that is there but does not refer pain actively. Instead when pressure is applied or the muscle is strained the structure containing the trigger point activates. Latent trigger points can influence muscle activation, which can result in a decrease coordination and balance. Key trigger points are ones that have pain in a referred pattern along a nerve pathway that activates a latent trigger point or creates it. Satellite trigger points are ones that are activated by a key trigger point. Often by treating a key trigger point will resolve satellite trigger points as well.
Patients who have trigger points often report regional, persistent pain that usually results in a decreased range of motion of the muscle in question. Often, the muscles that are used to maintain body posture are affected, namely the muscles in the neck, shoulders, and pelvic girdle. These muscles include the upper trapezius, scalene, sternocleidomastoid, levator scapulae, and quadratus lumborum. Palpation of a hypersensitive bundle or nodule of muscle fiber of harder than normal consistency is the physical finding most often associated with a trigger point. Localization of a trigger point is based on how the tissue feels and can be assisted by patient expressions of pain and by visual and palpable observations of local twitch response. Palpation can, and may very well, elicit pain over the palpated muscle and/or cause radiation of pain toward the zone of reference in addition to a twitch response.
Treatments vary, but can include modality treatments, massage, acupressure, heat or ice, diathermy, the “Spray and Stretch” technique and in chronic cases a trigger point injection may be needed. According to the American Academy of Family Physicians, “The Spray and Stretch technique involves passively stretching the target muscle while simultaneously applying dichlorodifluoromethane-trichloromonofluoromethane (Fluori-Methane) or ethyl chloride spray topically. The sudden drop in skin temperature is thought to produce temporary anesthesia by blocking the spinal stretch reflex and the sensation of pain at a higher center. The decreased pain sensation allows the muscle to be passively stretched toward normal length, which then helps to inactivate trigger points, relieve muscle spasm, and reduce referred pain”. As with all medical issues, the information provide in this blog should not replace an evaluation or treatment with a qualified healthcare provider.
Trigger point guide
Video on trigger point release