Ashi Points vs. Trigger Points: What Research Tells Us About Dry Needling

As acupuncturists, we have been navigating a quiet identity question for years. A growing number of physical therapists, chiropractors, and athletic trainers are inserting filiform needles into muscle tissue and calling it dry needling. Patients are receiving the work. Insurance is increasingly covering it. And our profession has been left to ask whether what they are doing is, in fact, our medicine practiced under a different name.

I want to walk through a piece of research that addresses this question with unusual clarity. The 2022 perspective paper by Lee, Lee, and Chae, published in Frontiers in Neuroscience, explores the relationship between Ashi points and myofascial trigger points (TPs) and proposes a model that reframes how we think about both. By the end of their analysis, the authors arrive at a conclusion that is worth our attention as acupuncturists, and especially as pelvic acupuncturists who depend on muscle specific needling every day in clinic.

The Three Categories of Acupuncture Points

To understand the argument, we have to remember how acupuncture points are classically organized. The traditional theory groups them into three categories: classical acupoints (CAs), extra acupoints (EAs), and Ashi points (Lee, Lee, and Chae, 2022).

There are 361 CAs that live along the 14 meridians, with defined locations based on anatomical landmarks and over 2,500 years of clinical history. EAs are points that do not belong to the 14 meridians but have well documented therapeutic properties and standardized anatomical locations. Together, CAs and EAs are referred to as "specified acupuncture points," meaning they have a name, a numbering code, and a fixed location.

Ashi points are different. They have no defined position. They are the points the client reports as painful, tender, or significant during palpatory examination. The term itself is thought to come from a combination of "A" representing the client's involuntary response and "shi" confirming the location (Lee, Lee, and Chae, 2022). Ashi points can appear anywhere on the body surface and are determined in the moment by the practitioner's hands and the client's response.

This last category is the one that matters most for the conversation about dry needling.

What Trigger Points Are

Myofascial trigger points were named within the Western biomedical tradition. They are described as hyperirritable sites within taut bands of skeletal muscle. When compressed, they can cause local pain, referred pain, muscle weakness, spasms, and autonomic responses such as vasoconstriction, hyperhidrosis, and somatovisceral changes (Lee, Lee, and Chae, 2022)

In other words, TPs are tender muscular nodules identified by palpation, treated by needle insertion, and known to refer pain in predictable patterns. The clinical experience of finding one and treating it is familiar to any acupuncturist who has ever needled the upper trapezius, the gluteus medius, or the levator ani.

The Shared Features

This is where the argument sharpens. Lee, Lee, and Chae outline the shared features of Ashi points and TPs in detail. Both are tender points. Both are identified through palpation. Both depend on the practitioner's tactile sensation and the client's subjective report. The number of points and their locations vary from person to person. And critically, the mechanical stimulation of both points by acupuncture or dry needling elicits the same physiologic responses: a local twitch response in TP treatment and a deqi sensation in Ashi point treatment (Lee, Lee, and Chae, 2022).

Two needles. Two hands. Two clients. The same tissue. The same response.

The authors note one meaningful difference. TPs are by definition located in the taut bands of skeletal muscle, while Ashi points can appear in any superficial part of the body, including non muscular tissue. TPs are most commonly found in pain disorders such as myofascial pain syndrome. Ashi points may also be present in non pain and non muscular conditions, including functional gastrointestinal disorders (Lee, Lee, and Chae, 2022).

This difference is not a contradiction. It is a containment relationship. TPs sit inside the larger category of Ashi points. They are the muscular subset. As Lee, Lee, and Chae write, "TPs are muscle specific Ashi points" (Lee, Lee, and Chae, 2022).

The New Model

The most useful contribution of this paper is a revised model of how the categories of acupuncture points relate to one another. The classical model treats CAs, EAs, and Ashi points as three mutually exclusive groups. Lee, Lee, and Chae propose instead that specified acupuncture points (CA + EA) and Ashi points overlap, and they divide the relationship into three subsets (Lee, Lee, and Chae, 2022).

Subset A contains specified acupoints that are not Ashi points. These are points with fixed anatomical locations and indications that extend beyond local pain, often for distal or systemic effects through the meridian system. PC 6 used for nausea and functional gastrointestinal disorders is a classic example.

Subset B is the overlap. These are points that are simultaneously specified acupoints and Ashi points or TPs. Many CAs and EAs sit directly over common trigger point locations. The authors cite SP 10 in the vastus medialis, LI 10 in the brachioradialis, and EX HN 5 in the temporalis as points where the specified location and the muscular TP location overlap (Lee, Lee, and Chae, 2022). The point has a meridian function. The point also has a muscular function. Both are correct.

Subset C is Ashi points that do not correspond to any specified acupoint. These include muscular Ashi points (the TPs) in areas without a named acupoint, such as the anterior deltoid muscle TP, as well as non muscular Ashi points (Lee, Lee, and Chae, 2022).

This model resolves a debate that has run for nearly fifty years. In 1977, Melzack, Stillwell, and Fox proposed that acupuncture points and TPs represent the same phenomenon in different labels, with a 71% correspondence between them. In 2003, Birch challenged that claim, arguing that the acupuncture points studied did not have the key features of TPs. Dorsher pushed back in 2008 with anatomic, clinical, and physiologic evidence of correspondence (Lee, Lee, and Chae, 2022). The Lee, Lee, and Chae model honors both sides. CAs and EAs are not equivalent to TPs as a whole category, because CAs and EAs include points with distal and systemic indications that have nothing to do with muscular pain. But where TPs sit, they are functionally indistinguishable from Ashi points.

Why This Matters in the Pelvic Bowl

In pelvic acupuncture, we work in muscle. Day in and day out. The levator ani complex, the puborectalis, the pubococcygeus, the iliococcygeus, the transverse perineal, the ischiocavernosus, the bulbospongiosus. The concomitant musculature of the back, abdomen, gluteals, and hips. We palpate. We identify the taut band or the hypertonic fiber or the tender nodule. We needle.

In the literature on chronic pelvic pain, this type of needling is given its own category. Lin and colleagues describe it as "local pelvic floor acupuncture" or "myofascial needling" and note its role in addressing muscle tightness, weakness, and recruitment in CPP (Lin et al., 2023). The mechanism is consistent with what Wang and colleagues describe in their work on acupuncture for chronic prostatitis and chronic pelvic pain syndrome: improved neuromuscular signaling, increased local blood flow, and restored pelvic floor muscle tone (Wang et al., 2023).

Read through the lens of the Lee, Lee, and Chae model, every pelvic floor TP we needle is a muscular Ashi point. Every gluteal trigger point we release is a muscular Ashi point. The work we are doing has a name in our medicine, a 2,500 year clinical history, and a body of contemporary research to support it (Lee, Lee, and Chae, 2022).

The Implication We Cannot Avoid

There is a position here that the research is asking us to hold.

If TPs are muscle specific Ashi points, then the act of inserting a needle into a TP is the act of needling an Ashi point. The procedure has a name. It has a tradition. It has a documented mechanism rooted in deqi, neuromodulation, blood flow regulation, and myofascial release. It has been ours for thousands of years.

Dry needling, when defined as the insertion of filiform needles into myofascial trigger points, is acupuncture. Not adjacent to it. Not inspired by it. It is the practice of our medicine, performed on a subset of points that the Lee, Lee, and Chae 2022 model identifies as functionally indistinguishable from Ashi points.

This is not a territorial argument. It is a clarity argument. Our profession works hard to establish standards, demonstrate efficacy, and be taken seriously among healthcare providers. When we allow a portion of our medicine to be renamed and offered by practitioners without our training, we obscure the very thing that makes our work coherent.

As acupuncturists, we treat the whole client. We integrate the biomedical structure, the patterns of disharmony, and the spiritual emotional state. We do not separate the muscle from the meridian or the body from the spirit. The pelvic floor TP we needle is held inside a meridian, a zang fu relationship, a jing jin pathway, and a shen that needs witness. The technique without the context is not the medicine. But the technique itself, performed on muscle tissue, is ours.

The research supports the position. Our hands know the position. It is time we name it.

References

Birch, S. (2003). Trigger point–acupuncture point correlations revisited. Journal of Alternative and Complementary Medicine, 9(1), 91 to 103. doi: 10.1089/107555303321222973

Dorsher, P. T. (2008). Can classical acupuncture points and trigger points be compared in the treatment of pain disorders? Birch's analysis revisited. Journal of Alternative and Complementary Medicine, 14(4), 353 to 359. doi: 10.1089/acm.2007.0810

Lee, S., Lee, I. S., and Chae, Y. (2022). Similarities between Ashi acupoints and myofascial trigger points: Exploring the relationship between body surface treatment points. Frontiers in Neuroscience, 16, 947884. doi: 10.3389/fnins.2022.947884

Lin, K. Y., Chang, Y. C., Lu, W. C., Kotha, P., Chen, Y. H., and Tu, C. H. (2023). Analgesic efficacy of acupuncture on chronic pelvic pain: A systematic review and meta analysis study. Healthcare (Basel), 11(6), 830. doi: 10.3390/healthcare11060830

Melzack, R., Stillwell, D. M., and Fox, E. J. (1977). Trigger points and acupuncture points for pain: Correlations and implications. Pain, 3(1), 3 to 23. doi: 10.1016/0304 3959(77)90032 X

Wang, H., Zhang, J., Ma, D., and Zhao, Z. (2023). The role of acupuncture and its related mechanism in treating chronic prostatitis/chronic pelvic pain syndrome. International Journal of General Medicine, 16, 4039 to 4050. doi: 10.2147/IJGM.S417066

Bio: Dr. Krystal Lynn Couture, DPT, LAc, founder of The Pelvic Acu, is an acupuncturist and physical therapist specializing in Pelvic Health. As a pelvic care acupuncturist, she brings to her practice a background steeped in both biomedical, TCM and holistic knowledge. She has an extensive formal background, with a Doctorate in physical therapy from Husson University as well as a Master of Science in acupuncture from the Institute of Taoist Education and Acupuncture. Krystal teaches Pelvic Care to Acupuncturists around the globe! www.thepelvicacu.com