by Howard M. Notgarnie, RDH, MA
The Associated Bodywork and Massage Professionals states that 80 to 90 percent of disease is stress-related. Massage promotes health by treating the muscle tension associated with stress. The physiologic effects of massage are increased circulation, immune function, joint flexibility, decreased edema and postsurgical adhesions, and healing of overworked muscles. Some premature babies grow faster when massage is part of their treatment. Massage can also help heal emotional trauma. The mechanisms of the latter two have not been determined, but spiritual as well as physiological effects are presumed.1
The American Massage Therapy Association indicates that women are more likely than men to seek massage. Almost one-third of consumers receive massage for medical reasons, and about one-quarter have massage for stress control and relaxation. Many massage therapists work in other forms of health care and have advanced training for particular techniques or treatment needs.2
Two primary philosophies explain disease processes and therapy as they pertain to massage: mechanical and energetic.
The mechanical theory stresses a physiological relationship between muscles and the effects of muscular trauma on tissues. Simons, Travell, and Simons write that overworked muscles can lead to the activation of trigger points in those muscles. Trigger points are muscle areas that are sensitive to compression in a latent or active state, in contrast to a healthy state, due to overwork, injury, or nerve pathology, and are spontaneously painful when active. Emotions and diseases of the joints or organs can also activate trigger points.
An experienced clinician will recognize a trigger point as a palpable nodule within a taut band of muscle. Formation of a trigger point causes shortening of the muscle. Contraction of a muscle in this condition causes muscular pain and dysfunction to become worse.
As a person adjusts to the limited range of motion caused by muscle shortening and pain, the trigger point refers pain to other areas such as secondary trigger points, which further restricts function. Besides pain, trigger points can cause sensory disturbance and excessive autonomic functions such as sweating, salivation, and tear production.
Trigger points cause early fatigue and delayed recovery due to the constant contraction of many fibers within the muscle, and weakness and poor coordination of muscles due to reflex inhibition of muscular activity. Painful trigger points can disturb sleep, particularly if the body position is aggravating them. The poorly rested individual may then become even more sensitive to those trigger points.
Models of trigger point formation
Several promising hypotheses may explain why trigger points form. One is that sarcomeres, the functional units of muscle contraction, pile up in a small area to form a contraction knot, leaving nearby sarcolemma devoid of sarcomeres. In effect, a chain is broken within a muscle fiber, and adjacent pieces of that chain can’t reach each other to straighten out.
A neurological explanation can be described as a positive feedback loop. A trigger point’s compression of a motor nerve increases that nerve’s stimulation of the muscle at the motor endplate, causing further muscle contraction.
The energy crisis hypothesis suggests that an event causing contracture, such as injury or overuse, causes the sarcoplasmic reticulum to release an excessive amount of calcium ions. A normal release of calcium produces contraction. Following that is relaxation, along with reuptake of calcium by the sarcoplasmic reticulum. However, the excessive release of calcium results in a high-energy demand to maintain the contraction induced by the presence of calcium, while at the same time the contraction causes ischemia, blocking the energy supply needed for calcium reuptake.3
Sohn and Sohn describe the energetic theory in terms of Amma, a branch of Traditional Chinese Medicine (TCM). Balance in the mind/body complex occurs through “manifestations of the polar forces,” yin and yang. Sources of disease such as constitution, emotion, microorganisms, and injury cause an imbalance to homeostasis by causing an excess or deficiency of qi (energy) along meridians that serve in a yin or yang fashion. Meridian points recognized for prevention and treatment of disease through massage and other TCM techniques are often identical to trigger points and other mechanical theories of massage.4
General treatment principles
Pain causes a limited range of motion. As a muscle with active trigger points undergoes stretching, the muscle reflexively contracts. Contraction from a shortened position is also painful. As other muscles take on the workload of the disabled muscle, those muscles will suffer similar consequences. Some muscles go into spasms when the trigger points of other muscles are activated. Likewise, a trigger point can inhibit activity of another muscle. When trigger points cause altered function for a long time, muscles may need to be retrained to their normal function once the trigger points become inactive.
Simons, Travell, and Simons stress that treatment of myofascial pain requires:
- Treating the underlying condition that activated the trigger points
- Recognizing the reality of the pain - it is not merely psychological
- Removing factors that overloaded the affected muscles
- Identifying visceral sources of referred pain, which may be a sign of serious illness
Dental hygiene considerations
Myofascial pain due to active trigger points can mimic other conditions. Those relevant to dental hygiene primarily include muscles of mastication, but - due to the interactions related to posture, nerves, blood vessels, and meridians - trigger points in distant muscles can have profound effects on oral health.3 For this reason, dental hygienists are a prominent part of the International Association of Orofacial Myology.5
Several pain patterns are associated with active trigger points in the muscles of mastication for which massage can be beneficial.
The masseter is a common cause of masticatory pain. The superficial layer of this muscle attaches to the zygomatic arch and zygomatic process of the maxilla. The deep layer attaches to the zygomatic process medial to the superficial layer. Both layers join the lateral side of the mandible at the angle and ramus. Trigger points in this muscle refer pain to the temple, eyebrow, posterior teeth, and nearby gingiva and bone, mimicking sinusitis. Trigger points in the deep layer may refer pain to the lateral pterygoid, temporomandibular joint, cheek, and ear or cause tinnitus without dizziness or hearing loss. Dizziness and hearing loss may indicate a neurological disorder. Trigger points in the masseter may also cause dental hypersensitivity and limited opening of the mouth.
Conditions that activate trigger points in the masseter include the sternocleidomastoid or upper trapezius, forward head posture, bruxism, parafunctional habits, loss of vertical dimension, prolonged time in a fully opened or closed position, emotional stress, and infections of teeth, gingiva, or surrounding tissue.
Trigger points in the masseter can restrict blood flow through the maxillary vein, causing increased fluid and stagnation in the temporal and infraorbital regions, leading to puffiness and incomplete opening of the eyes.
The temporalis attaches to the zygomatic, frontal parietal, sphenoid, and temporal bones in the temporal fossa, and closes the mandible with some retraction and contralateral deviation of the mandible through its attachment to the coronoid process and anterior ramus. The fibers of the temporalis fan out in a wide arc in its superior portion. Trigger points are close to the confluence of fibers just above the zygomatic arch and ear. Temporalis trigger points refer pain along the muscle fibers as well as the ala of the nose, maxilla, TMJ, and maxillary teeth.
Activation of trigger points can be caused by trauma, lengthy immobility, forward head posture, anterior displaced disk, exposure to cold temperature, or as a secondary activation from trigger points in the sternocleidomastoid, upper trapezius, suprahyoid, or infrahyoid muscles. Bruxism may be a result of trigger points and can be caused by folic acid deficiency, which can also cause restlessness in leg muscles. Hypothyroid clients are particularly susceptible to trigger point activation from a cold draft. Symptoms of active trigger points include headache at the temple or above and behind the eyes, or dental pain and hypersensitivity. Temporalis trigger points will not induce noticeable restricted opening but may cause abnormal occlusion.
The medial pterygoid connects the medial surface of the lateral pterygoid plate on the sphenoid bone to the medial surface of the mandibular angle. Its superior attachment often extends to the lateral surface of the palatine bone. The muscle’s primary function is to assist in closing and protrusion of the mandible. Unilateral contraction of the medial pterygoid will cause deviation of the mandible to the opposite side. It helps to keep the eustachian tube closed when resting. Clients with medial pterygoid trigger points often have difficulty identifying the exact position of pain, which centers on the TMJ and lateral pterygoid, with diffuse pain extending to the ear, throat, ramus, tongue, and palate. Clients will also feel stuffiness in the ear due to pressure against the tensor veli palatini as the latter muscle attempts to open the eustachian tube.
Diagnosis and treatment
When considering myofascial pain in the muscles of mastication, the differential diagnosis must include periapical pathology, TMJ derangement, cellulitis or neoplasms in the area, neurological disorders, and trigger points from other muscles. In addition to palpation, a test for the function of masticatory muscles is the two-knuckle test, in which the client places the proximal interphalangeal knuckles of the index and middle fingers of the nondominant hand in the mouth. They should be able to fit between the teeth with room to spare. In digital palpation, the clinician should feel for taut bands and nodules in the muscle. Snapping palpation is a more difficult technique to master. A positive result for active trigger points is a twitching muscle after the examiner plucks a taut band that contains a suspected trigger point.
The examiner should palpate the temporalis while the mouth is partly open. Clients can perform a stretch of the temporalis at home by pressing upward against the temples and skull behind the ears while opening the mouth comfortably and inhaling deeply.
Treatments include correcting poor posture, head or tongue position, addressing trigger points in the neck and shoulders, treating joint problems in the cervical vertebrae, and performing myofascial release techniques for all muscles of mastication bilaterally, since they are all connected through the mandible. Treatment of a primary trigger point usually resolves a secondary trigger point.3
Travell and Simons write that a rare trigger point in the soleus can cause facial pain and dysfunction. The soleus is the deeper of the two large calf muscles which is attached to the posterior border of the fibula and medial border of the tibia and inserting into the Achilles tendon. This muscle functions primarily for plantarflection of the ankle. It provides stability during walking, running, and jumping, pumps blood from the lower extremity back into general circulation, and has a high endurance level. A trigger point in the distolateral portion of the soleus can cause pain in the sacroiliac joint or the temporomandibular joint, with malocclusion that reduces to normal occlusion when the trigger point is treated.6 Incidentally, traditional Chinese medicine also recognizes this point as an important therapeutic target for headaches, visual disturbances,7 low back pain, and eye pain,8 which are areas of primary and secondary trigger point patterns as identified by Travell and Simons and Simons, Travell, and Simons.3,6
Traditional Chinese medicine identifies temporal trigger points on the gall bladder meridian and says that needling or massaging those areas is effective for toothaches, headaches, restricted mouth opening, stiff neck, and visual disturbances. Masseter trigger points are on the stomach meridian and are indicated for trigeminal neuralgia, toothache, facial paralysis, masseter spasm, and salivary dysfunction.8 Many additional points on the back and limbs help clients with pain in the head and neck.4 It would be well worth the time of scientists of the physiological philosophy to study the mechanisms more closely.
This article focuses on only four muscles affecting mastication to demonstrate the potential effects of trigger points. Dental hygienists should consider myofascial pain and its profound effects on the body when interviewing clients who complain of pain, paresthesia, or musculoskeletal dysfunction. Knowledge of these effects may lead the dental hygienist to refer clients to a massage therapist or a dental hygienist certified in orofacial myology. Continued interest may even lead the dental hygienist to add orofacial myology to his or her repertoire.
1 Associated Bodywork & Massage Professionals. Benefits of massage. 2006. Accessed Feb. 18, 2007, on http://www.massagetherapy.com/learnmore/benefits.php.
2 American Massage Therapy Association. Industry Fact Sheet. 2006. Accessed Feb. 18, 2007, on http://www.amtamassage.org/pdf/2005MTIndustryFactSheet.pdf.
3 Simons DG, Travell JG, Simons LS. Myofascial pain and dysfunction: the trigger point manual. 1990; Vol. 1, 2nd edition. Baltimore: Williams & Wilkins.
4 Sohn T, Sohn R. Amma therapy: a complete textbook of Oriental bodywork and medical principles. 1996. Rochester, Vt.: Healing Arts Press.
5 International Association of Orofacial Myology. What’s orofacial myology? 2007. Accessed March 4, 2007, on http://www.iaom.com/iaom_whatsom.html.
6 Travell JG, Simons DG. Myofascial pain and dysfunction: the trigger point manual. 1983; Vol. 2. Baltimore: Williams & Wilkins.
7 Acuxo: Acupuncture and resource. 2007 Accessed March 4, 2007, on http://www.acuxo.com/meridianPictures.asp.
8 Qi: The Journal of Traditional Eastern Health and Fitness. 2001. Accessed March 4, 2007, on http://qi-journal.com/tcmarticles/acumodel/listpoints.asp.
Myofascial release techniques
Stretch technique - Simons, Travell, and Simons describe the following technique to stretch the masseter, medial pterygoid, temporalis, and platysma:
• First, warm tissue with a compress to make the muscles as pliable as possible.
• Next, use a coolant spray or ice for a short period to anesthetize the tissue. The underlying muscle should still be warm. Apply the coolant parallel to the muscle fibers, primarily inferior to superior along the platysma and masseter and radially outward from the TMJ along fibers of the temporalis.
• Apply static traction upward on the temporalis with one hand while applying downward traction with the other hand, starting from the temporalis and working downward along the masseter and platysma, while being careful not to apply pressure medially, which would impinge the contralateral TMJ. While the operator applies downward traction, the client should open his or her mouth and inhale to help inhibit contraction of muscles that close the mouth.
Trigger point pressure - An experienced operator can feel taut bands and trigger point nodules with palpation using counter pressure from the bone and from fingers inside the mouth. When the operator finds areas of resistance in the muscle, pressure against those bands and nodules will cause relaxation. The operator should then follow the progress of relaxing muscle tissue by moving to the next area of tension.
Contract and release - Finally, in an active form of massage, where the client is working rather than relaxing the involved muscle, the client contracts the muscle against resistance for six seconds followed by relaxation and exhalation. As the client relaxes, the operator moves the point of resistance to lengthen the muscle.
Any of these techniques can be repeated several times in a therapeutic session. There are several other techniques available for myofascial release, but they are not considered massage techniques and are, therefore, beyond the scope of this article.
Howard M. Notgarnie, RDH, MA, practices dental hygiene in Colorado, and has eight years’ experience in official positions in dental hygiene associations at the state and local levels.