J Manipulative Physiol Ther 2002 (Jan); 25 (1): 63–70 ~ FULL TEXT
Joel Alcantara, DC, Gregory Plaugher, DC,
Darrel D. Klemp, DC, Chris Salem, DC
This study was funded by Life Chiropractic College West,
Hayward, California, the Gonstead Clinical Studies Society,
Santa Cruz, California, and the International Chiropractic
Pediatric Association, Media, Pennsylvania
OBJECTIVE: To describe the chiropractic care of a patient with cervical subluxation and complaints associated with temporomandibular disorder.
CLINICAL FEATURES: A 41-year-old woman had bilateral ear pain, tinnitus, vertigo, altered or decreased hearing acuity, and headaches. She had a history of ear infections, which had been treated with prescription antibiotics. Her complaints were attributed to a diagnosis of temporomandibular joint syndrome and had been treated unsuccessfully by a medical doctor and dentist.
INTERVENTION AND OUTCOME: High-velocity, low-amplitude adjustments (ie, Gonstead technique) were applied to findings of atlas subluxation. The patient's symptoms improved and eventually resolved after 9 visits.
CONCLUSION: The chiropractic care of a patient with temporomandibular disorder, headaches, and subluxation is described. Clinical issues relevant to the care of patients with this disorder are also discussed.
From the Full-Text Article: ] found morphologic changes such as flattening of the condylar head and articular eminence. Marginal irregularities were also observed, along with an abnormal relationship of the condylar head and fossa (ie, anterior positioning of the condylar head), resulting in reduced mobility.
The mandible or lower jawbone is the largest and strongest facial bone. Other than the auditory ossicles, it is the only skull bone that moves. Each ramus of the condyle has a posterior condylar process that articulates with the mandibular fossa and the articular tubercle of the temporal bone to form the TMJ. The TMJ is classified as a diarthrosis, or freely movable joint. As such, special movements involving the mandible are possible (ie, elevation, depression, protraction, and retraction). With respect to the TMJ, the 2 principal movements involved within the articulation are rotation and translation. Although there are normal variants, the first movement involves condylar rotation to 25 mm of interincisal opening, followed by translational motion of the condyle to a full range of mouth opening. In a normal articulation, a ratio of 4:1 between maximum opening and maximum translation is said to occur, as measured by lateral excursions to the opposite side or by protrusion. This ratio provides a guideline in determining dysfunctional motion at the TMJ and provides information in determining whether the limited ROM is intra-articular or extra-articular in nature. 
TMDs involve a constellation of clinical complaints, including pain and tenderness of the muscles of mastication and the TMJ, as well as of several sites along the head and neck. The pain is usually worse in the morning, and the patient commonly has a history of stress and difficulty in sleeping. Mandibular movement may be accompanied by crepitus, clicking, catching, and popping, resulting in restricted or deviated motion during opening or closing of the mouth. 
Joint sound has been studied as a possible indicator of dysfunction, such as that from internal derangement or focal degenerative disorders. Note, however, that joint sound in the absence of other accompanying signs and symptoms is not a pathologic indication. This said, joint sound may be indicative of a number of pathologic conditions, including an abnormal relationship between the condyle and the disk,15, 16 a dysfunctional relationship of the lateral ptyregoid muscles in relation to the levator muscles, [17, 18] an alteration of the ligaments of the disk, or irregularities and adhesions in the articular surfaces. [19, 20]
In 1952, Ekerstern  was the first to document the sounds of the TMJ in a group of 30 patients. Since that time, many more sophisticated studies have been performed. However, these studies are often in disagreement, particularly in the determination of the frequency range of joint sounds. Joint clicking is characterized as having a concentrated, single low-amplitude peak frequency during mandibular opening, whereas crepitus has its frequency distributed over a wider range and is characterized as rough, multiple, and sandy. The clicking sound has been attributed to local thickening of the layers of the articular surfaces, joint surface remodeling, condylar changes, subluxation, perforation and/or disc displacement. 
Less often, patients report sudden changes in bite (occlusion), hearing difficulties, tinnitus with pain in the face, temples, or preauricular region, and neck and shoulder pain. Synonyms for this disorder are Cosset’s syndrome, TMJ dysfunction, and craniomandibular disorder. Differential diagnosis should include other disorders such as dental pain; disorders involving the ears, nose, and sinuses; neuralgias; and headaches. In addition, diseases of the salivary glands must be considered because problems with these structures mimic the symptoms of temporomandibular pain and dysfunction. The feature distinguishing TMJ dysfunction from those listed previously is pain localized in and around the preauricular region accompanied by clicking or grating sounds and restriction on mouth opening.14 However, it must be stressed that the signs and symptoms of TMD are so interrelated and causative that a clear definition of the underlying agent is sometimes impossible. For example, it is quite possible to treat a TMD of muscular nature only to find that, as the myalgia and tension remit, there is articular damage where at first none was identified.
Myalgia originates primarily from nociceptive input as a result of stretching, forceful or sustained muscle contraction, ischemia, hyperremia as well as trauma, and inflammatory factors. Studies have shown that many TMD patients with myalgia have diffused muscle tenderness beyond the muscles of mastication, the head and neck region. In addition, it has been proposed that patients with masticatory myalgia may have impaired endogenous pain regulation. Such findings are relevant to chiropractic care because patients with chronic complaints of TMD may have pain sensation of the upper extremities as well. 
Various arthritides are known to involve the TMJ, including osteoarthritis, psoriatic arthritis, rheumatoid arthritis, and gout. However, for brevity of discussion, only 2 will be discussed: degenerative and inflammatory arthritide.
Rheumatoid arthritis is a chronic, systemic inflammatory arthritide characterized by the pattern of synovial joint involvement. We refer the reader elsewhere for a more detailed discussion of the pathophysiology of this arthritide.  Symptoms associated with the TMJ include pain during motion of the jaw, tenderness on palpation, and achiness, stiffness, and crepitus. One of the earliest signs of TMJ involvement is an anterior open bite. This is attributed to the loss of ramus height as a result of destruction of the condylar surfaces. This in turn may lead to subluxation of the TMJ. Contraction of the associated muscles will accentuate the process, and ultimately the patient will develop a lisp and lose the ability to incise. Capsular pain caused by synovitis or capsulitis is common, especially with increased jaw function and rapid and forceful jaw movement. Referred pain and secondary myospasms may ensue, resulting in a cycle of pain and muscle spasm. As pannus formation increases along the synovium, fibrous ankylosis of the joint takes place along with more pain. Adhesions cause translation of the contralateral condyle in protrusive, contralateral excursion, and opening. Periarticular inflammation results in swelling, pain, and decreased mobility of the mandible.  Although no specific radiologic changes are considered pathognomonic of rheumatoid arthritis, Syrjanen 26
Osteoarthritis is a common disorder affecting the TMJ. Its etiology is considered multifactorial, but 2 prevailing theories exist concerning its etiopathogenesis. The first involves the failure of articular chondrocytes to respond to degradation and repair, whereas the second involves the role of overloading forces on the articular cartilage. The cartilage is said to fail from the normal “wear and tear” caused by aging and by the failure to respond to single or multiple traumatic events. [27, 28] Etiologic factors may involve trauma, repetitive overloading as a result of teeth clenching and bruxism, and TMJ hypermobility, to list a few.
Radiographic features of TMJ osteoarthritis are pathognomonic for the cardinal features of osteophytes, subchondral sclerosis, and loss of joint space. Additionally, there is flattening of the condyles, which results in the flattening of the poeterior slope of the articular eminence. In later stages, joint arthrosis may occur with shortening of the ramus. [27, 29]
In the care of patients with TMD, no treatment seems to be palliative because a well-masked psychosocial stressor is the instigator of TMD. For this reason, proper clinical care demands a thorough and critical assessment of the whole patient before a plan of care is devised. Treatments for TMDs are varied and numerous. The approaches range from conservative to surgical.
Traditionally, an occlusional model of dysfunction was taken for TMDs, and treatment was aimed at modifying the patient’s bite. Occlusal adjustments are dental procedures in which the teeth are either realigned or ground down to accommodate proper bite and function.  Because this procedure is rather invasive and irreversible and because of the growing trend in the literature toward a nonocclusal etiology, this treatment has fallen from popularity.  Orthodontic treatment, however, is effective and much less invasive and adheres to the occlusal model of dysfunction. 
Surgery as a possible treatment for TMD applies to those patients with complaints thought to be of capsular origin. The most common surgical technique is arthrotomy, or open joint surgery. This type of surgery includes diskectomy, disk repositioning, and modified condylotomy. Arthroscopy is less invasive and growing in popularity. Although considered a successful treatment for TMDs, the number of appropriate surgical cases is small, and it should be remembered that, as with any surgery, morbidity is higher and failure more consequential when compared with conservative treatments. 
Pharmacologic treatment of TMDs work primarily through analgesic prescription. However, it is not currently clear whether this manner of treatment is better than placebo.  Over-the-counter, nonsteroidal anti-inflamatory drugs (ie, aspirin, ibuprofen, and acetomenaphin) are prescribed for inflammatory processes such as synovitis or myositis. Muscle relaxants, which are also strongly debated with regard to effectiveness, are commonly prescribed as well. The literature suggests that muscle relaxants have a beneficial effect in acute conditions but rarely perform well in chronic conditions.  With chronic conditions involving high levels of emotional stress, tranquilizing drugs such as benzodiazepines or tricyclic antidepressants are often prescribed. There is, of course, the danger of drug abuse, particularly with a “take as needed” philosophy. 
Physical medicine approaches, such as therapeutic ultrasound, acupuncture, trigger point work, and thermal therapies (cryotherapy, in particular), are very popular in the current literature and show good success rates for myogenic TMDs. Adjustments and manual therapies are also used, the goals of which are to improve the function between articular surfaces and to relieve muscle contractures. 
In the realm of chiropractic approaches to complaints involving extravertebral structures, corrective adjusting procedures directed at the TMJ are implemented in addition to adjustments to spinal subluxations. A more detailed description of such an approach is given by Bachman. 
To determine the extent of the scientific literature on the topic of chiropractic care of temporomandibular disorders, a MEDLINE search (1966-2000) was performed by using the subject headings “chiropractic,” “temporomandibular joint syndrome,” and “temporomandibular disorders.” Vernon and Ehrenfeld  reported on the chiropractic/dental management of a female patient with cervical myositis with radiculopathy and tenderness at the TMJ after a motor vehicle accident. The patient’s cervical spine pain was completely relieved by chiropractic care and the use of an intraoral orthotic device for malocclusion. Gregory  described the care of a patient with external derangement–type TMD by the use of sacro-occipital technique (SOT), including SOT category-II blocking to reduce a sacroiliac sprain. Saghafi and Curl  described the care of a 21-year-old woman who had a 4-year history of right-sided TMJ pain and clicking, along with limitations in mandibular opening. The patient was diagnosed with unilateral anterior displacement of the articular disk with adhesions to the articular eminence at the right TMJ. A specific joint manipulation was designed to reduce the anteriorly displaced and adhered TMJ disk, as well as adjustments to subluxations of the cervical spine. Chinappi and Getzoff  discussed a case of a 33-year-old woman seeking chiropractic care for centralized lumbosacral pain in addition to limited translation at the left temporal mandibular joint. Integrated dental, orthopedic, and craniochiropractic care ameliorated the lumbosacral pain and improved head, jaw, neck, and back function.
A recent publication by Knutson and Jacob  presented the dental/chiropractic comanagement of 2 patients: the first had migraine headache symptoms along with TMJ dysfunction, and the second had chronic hypomobility of mandibular opening, dizziness, headache, neck pain, and stiffness. Their paper addressed the theory that TMJ dysfunction may cause biomechanical alterations visible on radiographs. Their proposed explanation for this finding is based on a nociceptive/muscle contraction hypothesis, in which nociceptive signals from the TMJ may cause reflex contraction to the upper cervical musculature resulting in altered positioning (ie, subluxation) of the atlas. Case studies describe phenomenon and generate, confirm, or refute theoretical constructs. We endeavor to perform all of these and provide the following discussion on a possible bidirectional nature of the atlas and the TMJ with respect to dysfunction.
Much of the challenge in subluxation research has been the characterization of the bidirectional relationship between spinal subluxations (segmental or global) and neurologic dysfunction. In particular, how does such a dysfunction reflect somatic and visceral structure dysfunction? The patient presented in this case report was treated for complaints associated with TMD and subluxation. The management approaches were adjustments to findings of atlas subluxations. We propose that this lends support to the notion that upper cervical subluxation may lead to temporomandibular disorders. We discuss this subluxation concept from causal inference criterias  to provide a possible framework for future research in this area.
From the perspective of association, the idea that cervical spine dysfunction may lead to craniomandibular dysfunction and internal derangements of the TMJ follows the findings of the close relationship of the craniocervical-mandibular system. Consider the higher incidence of cervical pain in patients with dysfunction of the TMJ compared with those patients with TMD alone.  Further evidence for an association is exemplified in findings of TMJ injuries in postcervical whiplash. [46, 47]
With respect to temporality, one must always be cognizant of post hoc ergo propter hoc (Latin, meaning “after this, therefore on account of this”) in one’s interpretation. However, the temporal association between adjustments to the patient’s upper cervical spine and the amelioration of the patient’s complaints must be considered. An examination of the natural history of this disorder may provide a backdrop from which to make a comparison. Knowledge of the natural history of any disease provides valuable information for care and prognoses.
From clinical experience, we recognize that symptomatic TMJ disorders do spontaneously improve over time without treatment. This indicates a favorable natural prognosis in some patients. However, the natural course of this condition has not been well documented. Kurita et al  documented the natural course of untreated symptomatic individuals with TMJ disc displacement without reduction over a 2-1/2-year period. Based on a study population of 40 patients, at the end of 2 1/2 years, approximately 40% of the patients became spontaneously asymptomatic, one third had decreased symptoms, and approximately one fourth did not show any improvement. These findings were similar to previous findings by Lundh et al,  which showed that 28% of their patient population became pain-free, 36% improved, and 36% remained unchanged at 1-year follow up. It would seem, then, that about three quarters of patients with moderate to severe TMJ dysfunction would improve over time (ie, 2 1/2 years) without treatment. However, a recent publication by Gaudet and Brown  counters this conclusion, based on preliminary data from a large multi-site study involving 6500 patients. When 1212 treated patients were compared with 198 untreated patients, the hypothesis that TMD patients improve spontaneously was not supported. In support of chiropractic care, we point to the improvement in our patient’s complaints with each visit to the chiropractor, whereas her medical regimen did not improve her condition.
The plausibility that subluxation(s) in the cervical spine may lead to TMJ dysfunction and pain and that removal of cervical subluxations through chiropractic adjustments leads to an amelioration of dysfunction in the TMJ is based on the following. It is well known that sensory input from the vestibulocochlear and occular system along with proprioceptive receptors in the neck maintain proper head posture. A relationship has been found between the vestibular system and the neck musculature.  Vestibular spinal tracts excite motor neurons ipsilaterally, and some of these reach the spinal cord by means of the medial longitudinal fasciculus. Descending fibers of the medial longitudinal fasciculus then project to segments of the upper cervical spinal cord and activate motor neurons participating in movements of the neck. The tonic neck reflex (TNR), a component of the proprioceptive system, when activated by means of stimulation of the Golgi tendon organs, produces neck contractions that also maintain head posture. There may also be a neurophysiologic reflex relationship between the TNR and trigeminal reflex activity.  In addition, relationships exist between the descending tracts of the trigeminal nerve, including those from receptors from the TMJ, and the upper dorsal roots. Neurons from cranial nerves V, VII, IX, and X share neuron pools with neurons from the upper cervical segments. The presence of subluxations, particularly in the upper cervical spine, may produce aberrant sensory impulses to peripheral and central neuromuscular mechanisms as described previously, resulting in spinal dysfunction (ie, improper head posture). More specifically to our discussion, aberrant impulses from subluxations may result in a pathologic TNR, [51-53] causing dysfunctional head posture (ie, forward or anterior weight-bearing head posture). Studies have shown that changes in head posture will affect the position of the mandible.
Griffiths et al demonstrated in decerebrated rats that head position could be an important but complex factor in enhancing or depressing reflex activity differentially in the different muscles of mastication. Goldstein and Kraus  demonstrated by means of a kineograph that a forward head position was accompanied by an upward and backward movement of the mandible. Funakoshi et al  demonstrated that a craniocervical dorsoextension produced an increased activity in the temporal and masseter muscles. A pathologic TNR may also affect muscular activity in the temporal, pterygoid, and masseter muscles. Funakoshi and Amano  found that the TNR has a facilatory influence on the temporal and masseter muscles and demonstrated in decerebrated rats that head position increases their tonus. A hypertonic temporalis muscle may pull the condyle posterior, or a hypertonic lateral pterygoid muscle could pull the disk anterior leading to an articular disorder of the TMJ.
Chiropractors have long appreciated in their patients the variations and possible clinical significance of the cervical spinal curve, but the specific dynamics and etiologies involved in the determination of the ideal cervical spine configuration remains controversial. [58-60] Further research in this area is needed. More case reports with similar findings may address the issue of consistency of our findings based on repeated observations in a variety of patients. The finding that cervical subluxation is related to TMJ dysfunction seems to be coherent with preliminary findings in the scientific literature. Further research of the craniocervical-mandibular system involving experimental protocols will address the specificity (one cause-one effect) and biologic gradient (dose-response) criteria on the cause and effect issues of chiropractic adjustment on vertebral subluxations and their concomitant disorders.
We have discussed the chiropractic care of a patient with vertebral subluxation and complaints associated with a disorder of the TMJ. We have examined the possibility that subluxations of the cervical spine may result in a TMJ disorder and that removal of subluxations through adjustments may alleviate the extravertebral complaint. Because the incidence of these disorders is on the rise, it becomes increasingly important for today’s chiropractor to not only understand the pathology behind TMDs but also the myriad of care options available. The possibility that some of these disorders may be effects of subluxations through referred pain or dysfunction in the craniovertebral kinematic chain should be considered in the care of patients.
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