Lawrence H. Jones, D.O., in his publication, Spontaneous Release by Positioning and his later manual, Strain and Counterstrain, gives a rather concise explanation of the differences and similarities between his "tender points" and Janet Travell's earlier description of "trigger points". Jones also describes how tender points and trigger points are often intimately and closely related to the oriental "accupuncture points", while at the same time still managing to be somewhat different after all. Travell really referred to her findings as "myofascial trigger points", and she did this because she found that stimulating these points produced referred pain at other specific sites. Travell found that if she treated these myofascial triggers with vapocoolants, or injection of local anesthetics, that they could be effectively deactivated as sources of referred pain. Once you begin investigating the literature about these "sore spots", as I want to go down in history as the author of, you also run into another author (Chapman) who had something to say about site tenderness, but he was only cited in a more recent book about "An Endocrine Interpretation of Chapman's Reflexes" Obviously, Chapman had something to say about the whole subject at a time preceding Travell's first publication in 1947, but I have not been able to come up with the original text. Owens made note of the fact that Chapman related his sore spots to what he termed "visceral function", but anyone is entitled to call his work anything he wants, and visceral function must have had some relevance in 1937. Korr, is also recommended as an article to read as it goes into important detail on somatic joint dysfunction and gives what is probably the best scientific description of the process of dysfunction and spontaneous release.
Once you begin to seriously investigate the general area, you soon come up with the conclusion that one of the major differences between Jones' tender points and oriental medicine's acupuncture points is the fact that acupuncture points are generally located rather superficially in the skin and subcutaneous tissues, while tender points are generally deeper and at the fascial, tendenous, muscular, and periosteal layers of the body. Acupuncture points are needled by precisely placing the acupuncture needle through the skin and into the underlying acupuncture point whereupon the needle is rotated several times between the operator's finger tips. The needles are left in place for some time and may be twisted several times in the course of the treatment. Jones's tender points are approximately the same size, but are located within muscles, at the periosteal layers of bones, or within the tissue mass of tendons and fascial structures. Generally speaking, tender points are usually about 1 cm across, but the most tender, or highly reactive points, may only be about 3 mm in area.
All three techniques, and probably a few others, are based on a common observation that the acupuncture point, the trigger point, and the tender point are all manifestations of an organ, muscle, tendon, or joint dysfunction and that the point where the dysfunction can be monitored by the clinician does not have to have a direct geographic relationship to the area where the patient complaint is actually perceived. The mechanism by which all three systems exist, first as a sign of dysfunction (acupuncture, trigger, or tender point), or the physiologic process by which the therapeutic effect is obtained is not really entirely clear, but Korr comes closest to explaining counterstrain therapy when it comes to a rational scientific basis, and he relieves us of the necessity of learning to think in terms of oriental philosophy and culture as would be needed to truly understand and utilize classical acupuncture. Western culture demands the scientific approach and the associated need for hard scientific fact. Oriental culture allows acceptance of philosophical approximation and the inscrutable.
A good percentage of neural tissue in the spinal cord, for example, is functionally devoted to control and monitoring of normal physiologic processes. In addition to their efferent nerve supply, muscles are also provided with afferent nerve endings that allow the muscle to signal its state of contraction to the CNS. This muscular feedback is integrated within the CNS along with information arriving from the tendons, ligaments, and joint capsules to provide an awareness of both positions and rates of movement to the various parts of the body. Proprioception takes up a large portion of this neural function and many of the nerve endings of the sensory portions arise in structures known as muscle spindles, now neuromuscular spindles, and Golgi tendon organs. Numerous other types of free nerve endings exist in fascial and tendenous tissues beyond these structures and their obvious functions are to provide additional information to the central nervous system.
Neuromuscular spindles are basically length registering receptors. Structurally, they vary in length between 3 to 5 mm, are about 0.1 to 0.2 mm in diameter, and are enclosed in a loose and extendible connective tissue capsule. Generally, about 2 to 12 very narrow modified muscle fibers are enclosed within the capsule. Because of their structural incorporation within muscle tissue, they stretch when the muscle is stretched, and in doing this they form the basis of a neuromuscular servomechanism that is critical to purposefull and controlled muscular activity. Without some form of information feedback to the individual, a purposeful movement of a finger or an arm would be impossible. Visually observing a movement would even constitute a minimal form of information feedback, but even that control would be impossible in the dark. A sophisticated mechanism for generating information about rate of movement, extent of movement, strength of movement, etc. is critical to any meaningful movement. Without that critical information, all movement would cease to have any meaning to the organism and there wouldn't be much sense in having any structure larger than a small bundle of cells.
At the center of the spindle you can find a few larger fibers that are literally packed with cell nuclei. This area is made up of non-contractile fibers and is called the nuclear bag because of the numerous nuclei. The other fibers are usually much thinner and are referred to as nuclear chain fibers as their nuclei are lined up like a chain. There may be up to ten of the nuclear chain fibers within the spindle.
Spindles are ennervated by both efferent and afferent nerve fibers. Each nuclear bag fiber receives a large myelinated afferent nerve fiber from two sources, one spirals around the nuclear area and is called an annulospiral ending, or primary ending. Another secondary ending attaches outside of the nuclear bag area and are called secondary afferent endings.
Nuclear chain fibers receive afferent ennervation from the same primary myelinated fiber supplying the nuclear bag. Secondary nerve fibers terminate in what are termed flower spray endings on each side of the primary afferent endings. Functionally, primary efferent nerve endings (annulospirals) respond with information on degree and rate of muscle stretch, while secondary efferent endings only respond to degree of stretch.
Efferent nerve fibers ending at both static and dynamic efferent plates on the smaller intrarafusal muscle fibers together with those supplying the nuclear bag fibers effectively set up a system that can receive adjustment information from the CNS.
Spindles are most numerous in muscles which must have very precise descrimination of position. The masseter muscle is obviously one place where we would expect a lot of them exist, and they are very numerous in that muscle. Generally speaking, neuromuscular spindles are numerous in all of the muscles of mastication.
Obviously, there is some linkage between confused feedback information to, or from from, the servomechanism spindles as part of the onset and continuance of muscle spasm pain. Relief of muscle spasm pain by the mechanism of spontaneous release through counterstrain positioning is intimately tied into the neuromuscular spindle system. There is a finite time factor ( around 90 seconds) involved in the manipulative re-setting, or re-balancing of the spindle neural output message to the CNS, although these structures normally generate and receive nerve impulses at much higher rates of information exchange during normal function. The same process occurs in the following structures.
Also
referred to as GOLGI TENDON ORGANS, or NEUROTENDINOUS ORGANS, these structures
are found at the junction area between muscles, their associated tendons,
and in the aponeuroses on which the muscles attach. They are also encapsulated
structures and are generally slightly smaller than neuromuscular spindles.
They are usually ennervated by a large myelinated afferent fiber that ends
in small non-myelinated branches among small tendon fibers. The end fibers
are probably stimulated by being compressed and twisted between the collagenous
tendon fibers. Functionally, impulses from these organs tends to inhibit
the lower motor neurons in the spinal cord. This action may provide a protective
inhibition of muscular forces to prevent overstress damages to a muscle
and it's functional attachments.
Several types of sensory receptors are associated with synovial joints. Internal and external joint ligaments are supplied with receptor organs that closely resemble the Golgi Tendon Organs. The fibrous connective tissue capsules of joints are also suplied with numerous free nerve endings intertwined with the collagen fibers. Paciniform corpuscles and Ruffini type corpuscles are also fairly numerous. Paciniform corpuscles are known as MECHANORECEPTORS, and are thought to respond to compressive forces associated with joint movement. A lot of similar structures are seen in the periodontal ligament structure suspending the teeth in the alveolar processes, so the sensory information supplied to the CNS via this network must be superlative.
Proprioception is a critical function that allows fine control of all voluntary muscle activity by providing feedback information concerning rate of movement, amount of movement, and strength of movement. The process must first derive information from sensory units within the muscular unit, feed that information to the central nervous system at various levels, and return the process information from the central nervous system to the muscle unit in order to achieve any control at all. A motor nerve impulse to a muscle unit would be of little value if the response from the muscle unit was an all-or-none response of simple contraction. Everyone would be moving in uncontrolled jerks, or we'd all be suited up inside of a single cell membrane so that we could accomplish the most rudimentary actions. Increasing complexity of any organism implies process control as part of the bargain, and a great deal of the increase in complexity of an organism on a biologic level is increasingly sophisticated process control. However, with increased sophistication comes increased propensity for error in the program for relatively minor control processes.
In the presence of a joint dysfunction one of the contributing factors to the chronicity of the dysfunction is a disturbed, or altered proprioceptive picture. One of the common findings in muscle units affected by trigger point pain is a switched muscle, where the functional origin and insertion of the muscle is thought to be reversed. The physiologic effect of this switching is first, an abnormal performance as an effector when under normal neurologic motor control; second, an equally abnormal performance as an antagonistic unit while operating under inaccurate proprioceptive influence. Remember that trigger point pain can exist in both muscle units simultaneously, and most often, does.
To the individual suffering from myofascial pain and dysfunction problems it is not enough to inform them that they may have their pain and dysfunction for no other reason than that they have a somewhat screwed up neuromuscular feedback loop. For all practical purposes, their pain does not ever exist to them as a slight error in the control process. They hurt, and they want someone to help them get relief from their symptoms of pain and altered function.
Jones offers two definitions for strain and counterstrain therapy. 1. Strain and counterstrain: relieving spinal or other joint pain by passively putting the joint into its position of greatest comfort; or 2. strain and counterstrain: relieving pain by reduction and arrest of the continuing inappropriate proprioceptor activity. He said this was accomplished by markedly shortening the muscle that contains the malfunctioning muscle spindle by applying mild strain to its antagonists. In other words, the inappropriate strain reflex is inhibited by application of counterstrain. Jones also stresses one key factor that must be observed during any active therapy: The return from any position of comfort MUST be done very slowly, especially through the first few degrees of arc. Without careful attention to this clinical detail, release of the myofascial spasm may fail to occur.
Muscle makes up a very large portion of the body and generally, musculoskeletal dysfunction is often revealed by the presence of areas of tension and discomfort within muscles and limitation of motion at the articulations. Muscular dysfunction has as one of its early primary effects a mechanical restriction of the associated joints (bracing) and reduced range of motion. In the classic view of the dysfunction, the muscle may be thought of as trying to overcome the restraint supplied by the dysfunctional articulation. In the newer viewpoint, the muscle is viewed as the primary cause of the articular dysfunction. What comes first? The articular dysfunction, or the muscle dysfunction?
In the normal, homeostatic articulation, the musculature is not painful in any normal position. In a situation where the articulation is painful, there may be one muscle unit that is hyperextended (longer than normal) and the opposing, or antagonistic muscle hypershortened. As far as proprioceptive feedback to the central nervous system is concerned, the hyperextended muscle may be sending greatly increased information back to the CNS, while the hypershortened muscle sends little, or no proprioceptive information of process value. The net result is proprioceptive confusion, and that alone may be responsible for the onset of pain in the spastic muscles.
You may have begun to realize that counterstrain therapy is fairly easy to apply to the muscles, ligaments and fascia of an anatomic part such as an arm, elbow, or shoulder. These parts have a system of muscle relations that make application of the cardinal principle of therapy, shortening of the painful muscle unit, relatively easy. You may also begin to recognize that, while the principle should equally applicable to a muscle like the masseter, or temporalis, that the anatomy of the functional unit, the mandible itself, is a bit harder to close into any relationship that can effectively shorten these muscles much more that they are already. Short of extracting all the teeth, it isn't really mechanically possible to shorten the masseter and temporalis much beyond occlusal contact of the teeth.
Microanatomic studies of muscle usually describe the fact that muscle spindles are most numerous in the central belly of a muscle, while trigger points often are mainly associated with the ends of muscle where the spindles are absent, or at least much less numerous.
The masseter has a higher concentration of muscle spindles per unit volume than any other muscle, so this muscle has to be extraordinarily more sensitive to anything that disturbs proprioception. It also happens to be the most common indicator of problems with the dental apparatus.
It is possible to release a spasm in these muscles by firm digital pressure applied from the insertions toward the origins. You don't get much visible shortening, but the underlying muscle mass does get some effective shortening by the means of the digital pressures when the fingers of both hands are pushing toward the central mass of the muscle.
A rather unusual approach to releasing masseter and pterygoid spasm involves nothing more than gentle massage of the muscle unit between an introral finger of one hand versus an extraoral finger of the other hand. Imagine all of those rays of healing energy flowing out of those fingertips.
Sooner or later, you will run into therapies and therapists that really seem to defy the scientific facts as we (and I include myself) presently know or except them. I am the first to admit I do not understand a lot of these techniques, and I am only going to report on a few of them for your information, and so that you basically approach these ideas with an open mind. One thing that I have learned in twenty years is that there really isn't much that is NEW and totally UNIQUE. Therapeutics in this whole general area seems to undergo cycles where an older idea is rediscovered and possibly greatly enhanced by the application of newer technology that has only become available the second time around.
To start with, I always liked CRANIAL OSTEOPATHY, or CRANIAL MANIPULATION the best. Mariano Rocobado, a Brazilian Physical Therapist became a big name in this area, and I still see him mentioned from time to time in continuing education courses around the country. My own theory of what is going on is the best I can come up with, and that is the simple and time honored fact that these operators get right in there and TOUCH their patients. That simple fact of establishing a direct physical contact between clinician and patient is greatly downplayed in traditional therapeutics and should not be underestimated as an effective therapeutic tool. Chiropractors enjoy occasional success with jaw manipulation, but only occasional success. A lot of that success is basically due to the placebo effect that comes from just touching the patient and establishing a caring mannerism. When it comes to feeling the movement of the cranial bones in response to the circulation of spinal fluid, I must admit I can't feel a thing and have an equally hard time envisioning any physical motion of matured sutures in the cranium. When it comes to applying pressures to re-align the malrelation of cranial bones by digital pressures, I just remember how solid that old skull really is and chalk that up to salesmanship.
APPLIED KINESIOLOGY, or DENTAL KINESIOLOGY is another of the fringe areas that will probably make a comeback in your professional careers, if it has ever died out. George Eversaul tied applied kinesiology in with nutritional factors, and there may just be some interesting associations between somatic problems in general, and faulty nutrition.
There is something there. And like I said, the key seems to have been the personal interests of the clinician in his patients, and the fact that these guys all enjoyed the luxury of putting on the hands. Maybe the patients wanted to believe most of all.
Essentially, we, and I mean dentists and orthodontists especially, have a lot to offer in this whole area of head pain, if we only care to expend some effort to learn the basics and apply them. Keep an open mind and investigate different ideas. You will learn to pick out what you are comfortable with after a period of review and apply what you feel most comfortable with in treating your patients.
R. E. Brossman ©1995