Osteopathic physician Eileen DiGiovanna (1991) states: ‘Today many physicians believe there is a relationship among trigger points, acupuncture points and Chapman’s reflexes. Precisely what the relationship may be is unknown.’ She quotes from a prestigious osteopathic pioneer, George Northup (1941), who stated as far back as 1941:

One cannot escape the feelings that all of the seemingly diverse observations (regarding reflex patterns) are but views of the same iceberg the tip of which we are beginning to see, without understanding either its magnitude or its depth of importance.

Awareness of the reflex potential of the body surface widens the therapeutic potential of NMT, although deciding which of the many possible applications of reflex activity to utilize in diagnosis or treatment can be a daunting task. The discussion in this text of these reflex systems and classifications should not be taken as indicating recommendation for their use, merely recognition of the fact that they are widely used, and that NMT offers an additional means of access and employment of their potential.

Felix Mann (1983), one of the pioneers of acupuncture in the West, entered the controversy as to the existence, or otherwise, of acupuncture meridians (and indeed acupuncture points). Mann, in an effort to alter the emphasis that traditional acupuncture places on the specific charted positions of points, stated:

McBurney’s point, in appendicitis, has a defined position. In reality it may be 10cms higher, lower, to the left or right. It may be one centimetre in diameter, or occupy the whole of the abdomen, or not occur at all. Acupuncture points are often the same, and hence it is pointless to speak of acupuncture points in the classical traditional way. Carefully performed electrical resistance measurements do not show alterations in the skin resistance to electricity, corresponding with classical acupuncture points. There are so many acupuncture points mentioned in some modern books, that there is no skin left which is not an acupuncture point. In cardiac disease, pain and tenderness may occur in the arm however this does not occur more frequently along the course of the heart meridian, than anywhere else in the arm.

Hence, Mann concludes, meridians do not exist, or – more confusingly perhaps – the whole body is an acupuncture point!

Leaving aside the validity of Mann’s comment, it is true to say that if all the multitude of points described in acupuncture, traditional and modern, together with those points described by Travell and co-workers, Chapman, Jones and Bennett (see later in this chapter), were to be placed together on one map of the body surface, we would soon come to the conclusion that the entire body surface is a ‘potential acupuncture point’.

This realization is supported by Speransky’s findings from the 1930s, as discussed in Chapter 3.

Are all tender points trigger points?

A number of respected researchers and clinicians are frequently in error when they describe localized soft tissue areas that palpate as sensitive, but that do not refer symptoms elsewhere, as trigger points.

Certainly a trigger point will always be palpable, and will always be sensitive to pressure, but then so will most other ‘points’, whether these be Chapman’s reflexes, Gutstein’s myodysneuria points, Jones’s tender points, or acupuncture alarm points. These, however, will not necessarily refer painful symptoms to distant sites in the obvious manner displayed by trigger points.

This is not to say that any ‘tender’ or sensitive point cannot become a trigger point, since, clearly, before it is active, a trigger point has to evolve, and in its earlier stages will be painful, sensitive or tender, but may at the time of palpation not be sufficiently sensitized and hyperreactive to refer pain and other symptoms. If a point ‘belonging’ to any of the various classifications discussed below does refer symptoms in the manner of trigger points, then it can be so classified and treated.

Distinguishing features of myofascial trigger points

(modified from Simons 2002)

• Active myofascial trigger points produce regional pain complaints and not bodywide pain and tenderness.

• Not all tender points are myofascial trigger points, but all myofascial trigger points are tender.

• Referred tenderness, as well as referred pain, is characteristic of a myofascial trigger point.

• All myofascial trigger points are associated with a taut band.

• Not all taut bands are palpable (requires sufficient palpation skill and accessibility).

• All active myofascial trigger points cause a clinical pain (sensory disturbance) that is familiar to the patient.

• Only an active myofascial trigger point, when compressed, reproduces the clinical sensory symptoms that are familiar to the patient.

• However, a latent myofascial trigger point produces no clinical sensory (pain or numbness) complaint that is familiar to the patient.

Some of the major ‘point’ classifications involving reflex activity, and with a diagnostic potential, are considered in this chapter, in alphabetical order (not in order of apparent importance).

Mechanotransduction, fascial pathways, and endocannabinoid influences – some recent advances

Before looking at a selection of point classifications, involving reflex activity, the evidence of recent research relating to the process of mechanotransduction requires a brief introduction, as does introduction of endocannabinoid influences.

We have seen earlier in this chapter that there exist in many individuals discrete localized areas that generate pain, and/or other symptoms (often at a distance), as a result of local or central sensitization.

It is therefore important to be able to demonstrate evidence that these can:

1. be identified via palpation, and

2. be manipulated/treated manually via stretching or compression – for example – or by tool assisted means (e.g. acupuncture).

Assessment/palpation will be investigated in Chapter 5, while therapeutic approaches will be described in Chapters 6, 7, 8, 9, 10 and 11.

But what are the mechanisms associated with influencing symptoms and tissues at a distance?

As we have seen, neurological explanations have been at the forefront of attempts to explain reflex influences. However, there have been other recent developments in our understanding of how manual treatment can influence distant tissues, for example via the biochemical and other processes involved in what is termed mechanotransduction; and also via the release of endocannabinoids.

Mechanotransduction

Burkholder (2006) notes:

There are many ways by which deformation of a myofiber might be converted to a biochemical signal. When a deformation is imposed on a muscle, changes in cellular and molecular conformations link the mechanical forces with biochemical signals, and the close integration of mechanical signals with electrical, metabolic, and hormonal signaling may disguise the aspect of the response that is specific to the mechanical forces. The mechanically induced conformational change may directly activate downstream signaling and may trigger messenger systems to activate signaling indirectly.

A veritable cascade of biochemical changes result from mechanical deformation of tissues, involving calcium, insulin and a variety of complex substances that signal to other tissues ‘downstream’.

It seems probable that such signalling can be modulated, directed, to achieve positive changes, via appropriate manual methods of treatment (Levin 2000).

Fascial communication

Closely linked to these ideas is an increased awareness of fascial connections that link distant, as well as local, areas of the body (Myers 2008, Huijing & Baan 2001).

Langevin et al (2005) have proposed fascia/connective tissue as a communication system:

Connective tissue may function as a previously unrecognized whole body communication system. Since connective tissue is intimately associated with all other tissues (e.g. lung, intestine), connective tissue signaling may coherently influence (and be influenced by) the normal or pathological function of a wide variety of organ systems … connective tissue functions as a body-wide mechanosensitive signaling network [involving] three categories of signals: electrical, cellular and tissue remodeling, each potentially responsive to mechanical forces over different time scales.

Khalsa et al (2005) report that ‘Langevin’s research describes a common feature of manual therapies – the application of mechanical forces to connective tissues. Immediate (viscoelastic and mechanotransduction) and delayed (remodeling) connective tissue effects of these forces may contribute to the mechanism of these therapies.’

Endocannabinoids

In the 1990s a new class of self-generated pain-relieving substances was identified in the body, the endocannabinoids. These substances mimic the pain-relieving and euphoria-generating effects of the use of cannabis, and help to explain its illegal use by many chronically pain-ridden individuals (Degenhardt 2007).

As McPartland & Simons (2007) explain:

The endocannabinoid (eCB) system, like the better-known endorphin system, diminishes nociception and pain, reduces inflammation in myofascial tissues, and plays a role in fascial reorganization. The overall role of the eCB system can be summarized as ‘resilience to allostatic load,’ a phrase synonymous with health. Practitioners wield several tools that upregulate eCB activity, including myofascial manipulation, diet and lifestyle [particularly exercise].

Summary

NMT (and other soft tissue approaches to treatment of somatic dysfunction) clearly ‘deform’ tissues (compression, shear, stretch, etc.), albeit briefly, and over and above the local effects on tissue, the signalling potential that follows remains an intriguing area for further research. At the same time endocannabinoid influences are likely candidates to explain at least some of the local and distant effects of manual treatment such as NMT.

Empirical clinical evidence certainly indicates that distant influences are achieved using NMT, and these current research areas appear to explain some of the mechanisms.

Acupuncture points

Soft tissue changes often produce organized discrete areas that act as generators of secondary problems. A repetitive question arises as to whether traditional acupuncture points are in fact the same as trigger points (Fig. 4.1).

Figure 4.1A, B Location of some important acupuncture points on the head and neck. Research indicates that over 75% of defined acupuncture points are also sites of common trigger points.

The location of acupuncture points, with their fixed anatomical locations, are capable of corroboration by electrical detection, each point being evidenced by a small area of lowered electrical resistance.

When ‘active’, possibly due to reflex factors, these points become even more detectable, as the electrical resistance lowers further. The skin overlying them also alters and becomes hyperalgesic and not difficult to palpate as differing from surrounding skin. Active acupuncture points also become sensitive to pressure and this is of value to the therapist because the finding of sensitive areas during palpation or treatment is of diagnostic importance. Sensitive and painful areas that do not have detectable tissue changes as part of their make-up may well be ‘active’ acupuncture points, or tsubo, which means ‘points on the human body’ in Japanese (Serizawe 1976).

Not only are these points detectable and sensitive, but they are also amenable to treatment by direct pressure techniques. They therefore display, in almost all particulars, the same features as trigger points.

Acupuncture points and their morphology

Pain researchers Wall & Melzack (1989), and others (Travell & Simons 1992, Melzack et al 1977), maintain that there is little, if any, difference between acupuncture points and most trigger points.

Dorsher (2004), carefully compared the location of 255 trigger points, as identified by Travell and Simons, with 747 acupuncture points as identified by the Shanghai College of Traditional Medicine (Chen 1995):

The findings were that 92% of TPs had anatomically corresponding acupuncture points, 83% of these points had similar regional pain indications, and 87% of myofascial TPs had referred pain patterns that are identical or nearly identical to the corresponding acupuncture points’ meridian distributions.

The conclusion was: TPs are essentially a ‘rediscovery’ of the 2000-year-old acupuncture tradition (a subset of acupuncture points). As will be noted below, not all researchers or clinicians agree with these findings (Birch 2008).

The morphology of acupuncture points has been studied, notably by Bosey (1984).

Some of his major conclusions, in summary, are as follows:

• Points are situated in palpable depressions (‘cupules’).

• The skin (epiderm) over the point is a little thinner at the cupule level, under which lies a fibrous cone in which there is frequently found either a neurovascular formation, or simply a cutaneous neurovascular bundle.

• Free nerve endings are noted, and the presence, beneath the point, of Golgi endings and Pacini corpuscles is common.

• Connective tissues lie below at varying depths.

• Fascia and aponeurosis are noted and a passage of vessels and nerves, through the fascia, is very often found under the acupuncture point.

The practice of manipulating the needle in acupuncture imposes a degree of traction on the underlying (muscular) tissue, which imposes stimulation on underlying receptor organs. Fat is also a common factor in the morphology of points, and this, and the connective tissue, is thought to be a key factor in the achievement of the ‘acupuncture sensation’ that accompanies successful treatment. The conclusion reached is that a number of tissues are simultaneously affected needling – a phenomenon confirmed by Langevin (2006), supporting the mechanotransduction mechanisms discussed earlier.

Some points, when dissected, showed that neurovascular structures lie immediately below the point, which could account for the particular effects noted by such points being treated. This is of interest to those using Bennett’s neurovascular points. The implications for those practitioners not employing needles, and who rely on pressure techniques in order to provide stimulus or sedation to such areas, is that, if accurately applied, the effects of pressure should be identical (to needle acupuncture), especially in relation to pain control.

Acupuncture and applied kinesiology

An attempt to correlate the various reflex systems and methods has been made by the American chiropractor George Goodheart. His system of applied kinesiology involves testing muscle groups for weaknesses and then, depending upon the results of such tests, using various massage and pressure techniques applied to specific locations (points) in order to normalize function. These points correspond to Chapman’s reflexes, acupuncture points and other less well known reflex systems. Many of Goodheart’s techniques, theories and methods support and utilize methods that are in line with NMT.

Acupressure and pain thresholds

It has been shown that pain thresholds can be dramatically raised by pressure techniques applied to specific points. Researchers at the Peking Medical College conducted complex experiments which demonstrated that finger pressure acupuncture produced a rise of 133% in pain threshold of rabbits (using radiant heat as the painful stimulus). When cerebrospinal fluid was perfused from one rabbit to another after such experiments, the recipient rabbit was found to have achieved a rise in pain threshold of up to 80%. This suggested the presence of hormone-like substances produced by the brain in response to the original acupressure stimulus. These substances are now known to be enkephalins and endorphins, and these play a role in NMT pain control. The point used in these tests was equivalent to the acupuncture point known as Bladder 60, posterior to the ankle (externally) and just anterior to the Achilles tendon.

Acupuncture points and trigger points: not all agree that they are the same phenomenon

As outlined earlier, because they spatially occupy the same positions in at least 75% of cases (Wall & Melzack 1989, Dorsher 2004, Dorsher & Fleckenstein 2008) there are strong indications that trigger points are in fact no more than active acupuncture points. Wall & Melzack (1989) have concluded that: ‘trigger points and acupuncture points when used for pain control, though discovered independently and labelled differently, represent the same phenomenon’.

Baldry (1993) does not agree, however, claiming differences in their structural make-up. He states:

It would seem likely that they are of two different types, and their close spatial correlation is because there are A-delta afferent-innervated [fast transmitting receptors with a high threshold and sensitive to sharply pointed stimuli or heat produced stimulation] acupuncture points in the skin and subcutaneous tissues immediately above the intramuscularly placed, predominantly C afferent-innervated [slow transmitting, low threshold, widely distributed and sensitive to chemicals – such as those released by damaged cells – mechanical or thermal stimulus] trigger points.

Clearly, stimulation of an area that has, beneath the contacting instrument or digit, both an acupuncture and a trigger point will influence both types of neural transmission and both ‘points’. Which route of reflex stimulation is producing a therapeutic effect, or whether other mechanisms altogether are at work – endorphin or endocannabinoid release, as examples – is therefore open to debate. This debate can be further widened if we include the vast array of other reflex influences identified by other systems and workers, as discussed later in this chapter.

Whereas traditional oriental concepts focus on ‘energy’ imbalances in reaction to acupuncture points, there exist also a number of Western interpretations.

Melzack et al (1977) have assumed that acupuncture points represent areas of abnormal physiological activity, producing a continuous low-level input into the central nervous system (CNS). They suggested that this might eventually lead to a combining with noxious stimuli deriving from other structures, innervated by the same segments, to produce an increased awareness of pain and distress. They found it reasonable to assume that trigger points and acupuncture points represented the same phenomenon, having found that the location of trigger points on Western maps, and acupuncture points used commonly in painful conditions, showed a remarkable 75% correlation in position.

It is interesting that the link between the source of pain or tender points, and the referred area of pain noted in trigger points, in many instances seems to travel along the routes of traditional acupuncture meridians, but certainly not always. Spontaneous pain in such a point, according to acupuncture tradition, indicates the need for urgent attention. It is not the intention of this book to provide instruction in acupuncture methodology, nor necessarily to endorse the views expressed by traditional acupuncture in relation to meridians and their purported connection with organs and systems. However, it would be short-sighted to ignore the accumulated wisdom that has led many thousands of skilled practitioners to ascribe particular roles to these points, for example Alarm, Associated and Akabane points as described in this chapter.

As far as a manual therapy is concerned, there seems to be value in having awareness of the reported roles of particular acupuncture points, and of incorporating this into diagnostic and therapeutic settings.

As we palpate and search through the soft tissues, in basic neuromuscular technique, we are bound to come across areas of sensitivity that relate to these points. They are also often found to overlap with neurolymphatic and neurovascular points, as described elsewhere in this text.

For example, reflex number 19 in Chapman’s reflexes, which relates to the urethra, is identical to the neurovascular point of the bladder, and the acupuncture alarm point of the Bladder meridian. Careful comparison shows many such overlaps.

General guidance as to how to treat acupuncture points, which are sensitive, must relate to whether a stimulating or sedating effect is desired. The body often seems to utilize therapeutic stimulation to its best advantage.

Selye has shown us (see Ch. 1) that homeostatic mechanisms are at work, so that any stimulus, if appropriate and not excessive, can result in a beneficial response. In accord with the methods used in treating neurolymphatic and neurovascular points (described elsewhere in this chapter) it is suggested that, to some extent, the ‘feel’ of the tissues be allowed to guide the practitioner. A change (in the sense of a release of tension, or a softening, or a sensing of a gentle pulsation in the tissues) is often an indication of an adequate degree of therapy. In order to sedate what is an overactive point, up to 5 minutes of sustained or intermittent pressure, or rotary contact, may be required.

For stimulation, the timing could involve between 20 seconds and 2 minutes. By this time, some degree of change should be palpable. As must be clear, if pressure is sustained beyond a certain point quite the opposite effect will be achieved. This is a common natural phenomenon which occurs in response to all factors in life that are initially stimulating. If prolonged, they become enervating or exhausting, and in terms of therapy this is undesirable unless anaesthesia is required.

A short cold (water) application, for example, will stimulate, whereas a long one will sedate, and too much can kill. The words of Speransky and Selye should be recalled and the minimum effort used, consistent with achieving a response.

We have noted previously that many of the different reflex systems have points that seem to be interchangeable, and that many of these are traditional acupuncture points. In terms of local pain, the view of Chifuyu Takeshige (Takeshige 1985), Professor of Physiology at Showa University, is that: ‘The acupuncture point of treatment of muscle pain is the pain-producing muscle itself.’

Respected acupuncture clinicians, such as George Ulett, suggest that ‘acupuncture points are nothing more than time honoured muscle motor points’. Professor C. Chan Gunn, however, finds this too simple an explanation, and states: ‘Calling acupuncture points “motor points” or “myofascial trigger points” is too simple. They are Golgi tendon organs.’ These, and other researchers, are quoted by Stephen Botek, Assistant Professor of Clinical Psychiatry, New York Medical College (Ernst 1983).

Botek (1985) believes that ‘myofascial needling’ is the term of choice to define the type of acupuncture that dispenses with traditional explanations as to the effects of acupuncture. The points utilized in one study were Large Intestine 4 (Hoku) in the web between thumb and the first finger, and Stomach 36 (Tsu san li) below the knee. The study recorded skin temperature of the face, hands and feet. It was found that, compared with a resting period, both manual and electrical stimulation of both points induced a general warming effect. This was immediate in the face (Lewith & Kenyon 1984) and appeared after 10–15 minutes in hands and feet. The temperature increase was notably more marked after manual acupressure than after electrical stimulation. Manual stimulation of these points was shown to be more effective than other forms of stimulation.

Lewith & Kenyon (1984) point to a variety of suggestions having been made as to the mechanisms via which acupuncture, or acupressure, achieves pain-relieving results. These include neurological explanations such as the ‘gate control theory’. This, and variations on this theme, look at the various structures of the CNS and the brain in order to define the precise mechanisms involved in acupuncture’s pain-relieving action.

This, in itself, is seen to be an incomplete explanation, and humoral (endorphin, endocannabinoid release, etc.) and psychological factors, are also shown to be involved in modifying the patient’s perception of pain.

A combination of reflex and direct neurological elements, as well as the involvement of a variety of secretions, such as enkephalins and endorphins, is thought to be the modus operandi of acupressure, and probably of all of the various systems of reflex activity discussed in this section (neurolymphatics, etc.).

Many of the points of referred pain and tenderness used in Western medical diagnosis are also acupuncture points, for example: