Tender Point vs. Trigger Point

Are They the Same Thing?

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When you read about fibromyalgia (FMS), it's common to come across the terms "tender point" and "trigger point." They're often used interchangeably, but they're actually very different from each other.

Why is there so much confusion about these two terms? At first glance, it seems that the medical community is divided over whether they are the same thing. You can even find a lot of websites and books, written by healthcare professionals, who talk about diagnosing FMS with trigger points and treating it with trigger-point injections.

However, when you look at the scientific literature, it quickly becomes clear that, while tender points and trigger points both appear to play roles in FMS, they are not the same thing. Some of the confusion may be because it's extremely common for people with FMS to also have myofascial pain syndrome (MPS), which involves chronic pain from multiple trigger points. (Some doctors also question whether FMS and MPS are different illnesses.)

How They're Different

Let's operate under the assumptions that FMS and MPS are separate illnesses, since that's what the people who research them believe, and that tender points and trigger points are different. First, let's look at definitions of the two terms:

  • Tender Point: One of 18 specific places on the body that are used to diagnose widespread pain and tenderness in FMS. The presence of widespread tender points helps your doctor diagnose FMS.
  • Trigger Point: Also called myofascial trigger point (TrPs or MTrPs). A trigger point is a small, hard knot in the muscle (myo) or connective tissue (fascia) that won't relax. TrPs are painful when pressure is applied. In the absence of pressure, they may cause pain in the immediate area and/or cause pain in a different area. This is called a referred pain pattern. Chronic pain from multiple TrPs is called myofascial pain syndrome.

    One 2011 study (Mense) describes several key differences between them, which you'll find in the table farther down the page. It should be noted that the authors of that study do say that many of their statements are hypothetical because FMS and MPS aren't fully understood.

    Trigger Points in Fibromyalgia

    Multiple studies show that TrPs can in fact play significant roles in FMS, as a cause of significant pain, and possibly even in a causal role.

    In one study (Alonso-Blanco), researchers wanted to see whether they could create the seemingly random, spontaneous pain of fibromyalgia by manipulating their TrPs. It turns out, they were able to fully reproduce FMS pain that way. They also found that the participants with more active TrPs had more intense spontaneous pain.

    What they concluded was that pain from TrPs may help lead to something called "central sensitization," which is believed to be an underlying mechanism of FMS. Essentially, central sensitization means that the central nervous system (the brain and spinal cord) are hypersensitive to pain and other stimuli, such as light, noise and temperature. Central sensitization is also believed to play a role in migraines, osteoarthritis and chronic fatigue syndrome.

    This theory is supported by other studies, including one (Ge 2010) that says most of the tender points are at common TrP sites, and another that suggests FMS pain is largely due to TrPs (Ge 2009).

    A review of literature (Kuncewicz) on tender points and trigger points states that confusion between the two and interchangeable use of the terms can lead to misdiagnosis, which in turn leads to ineffective treatment.

    And that really gets to the heart of it -- we need accurate diagnoses to find accurate treatments. FMS requires different treatment than MPS. For the many people who have both, it's essential to treat both in order to alleviate symptoms and regain function.

    Sources:

    Alonso-Blanco C, et. al. The Clinical journal of pain. 2011 Jun;27(5):405-13. Multiple active myofascial trigger points reproduce the overall spontaneous pain pattern in women with fibromyalgia and are related to widespread mechanical hypersensitivity.

    Ge HY, et. al. Pain. 2009 Dec 15;147(1-3):233-40. Contribution of the local and referred pain from active myofascial trigger points in fibromyalgia syndrome.

    Ge HY, et. al. The journal of pain. 2010 Jul;11(7):644-51. The predetermined sites of examination for tender points in fibromyalgia syndrome are frequently associated with myofascial trigger points.

    Ge HY. Current pain and headache reports. 2010 Oct;14(5):339-45. Prevalence of myofascial trigger points in fibromyalgia: the overlap of two common problems.

    Kuncewicz E, Samborski W. Chirurgia narzadow ruchu i ortopedia polska. 2009 Nov-Dec;74(6):367-71. (Abstract referenced. Article in Polish.) Tender points and trigger points - differences and similarities.

    Mense S. Schmerz. 2011 Feb;25(1):93-103. (Abstract referenced. Article in German.) Differences between myofascial trigger points and tender points.

     

    TrPTender Point
    Palpable nodule (small mass)No palpabe nodule
    Hyperalgesia and allodynia (pain types) at site onlyHyperalgesia/allodynia at and away from site
    Usually isolated (single)Multiple by definition
    Refer pain away from siteHyperalgesia/allodynia at and away from site
    Local twitch responseNo local twitch response
    Biopsy shows contractionBiopsy shows nonspecific microscopic changes
    Evidence suggests peripheral nerve involvement*Evidence suggests central nervous system involvement

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