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Possible manifestation of temporomandibular joint dysfunction on chiropractic cervical x-ray studies
Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999 0161-4754/99/$8.00 + 0 76/1/94867 © 1999 JMPT
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CASE REPORTS Possible Manifestation of Temporomandibular Joint Dysfunction on Chiropractic Cervical X-ray Studies Gary A. Knutson, DC,a and Moses Jacob, DC b
ABSTRACT Objective: Our purpose was to show that biomechanical alterations toward and away from normal on x-ray studies may be the result of changes in temporomandibular joint dysfunction and to discuss possible neurologic explanations for this phenomenon. Clinical Features: Two patients are discussed; the first had migraine headache symptoms, and the second had chronic hypomobility of mandibular opening, dizziness, headache, and neck pain and stiffness. In both patients mensuration changes in different types of cervical x-ray studies were noted in conjunction with exacerbation of, and elimination of, temporomandibular joint dysfunction.
INTRODUCTION Temporomandibular joint dysfunction (TMD) is the general term used for any disorder that affects the temporomandibular joint (TMJ). The cause of TMD is considered to be multifactorial and has been attributed to occlusal disorders; bruxism; thermal, chemical, or electrical causes1; and psychogenic/emotional factors.2 Some of the most common causative factors are trauma (both microtrauma and macrotrauma) and iatrogenic (excessive mouth opening during dental procedures or surgical anesthetic intubation and faulty cervical traction). A major traumatic cause of TMD is a hyperextensionhyperflexion injury during motor vehicle accidents.1 Numerous authors have detailed the mechanics of TMD as a direct or secondary result of traumatic “whiplash” injury.1,3,4 Symptoms of TMD disorders include facial or neck pain, headaches, and TMJ noises, including popping, clicking, and crepitation. Other symptoms associated with TMD include tinnitus, vertigo, and referred pain in the preauricular, frontal, and retro-orbital areas, as well as numbness of the fingers.5 The correlation of TMD with cervical spine disorders has been detailed by several authors,3,6,7 including one study that demonstrated a 70% cervical spine dysfunction in a patient population with TMD.8 By use of electromyelography in patients with myogenic craniocervical mandibular dysfunca
Private practice of chiropractic, Bloomington, Indiana. Private practice of chiropractic, Novato, California. Submit requests for reprints to: Dr Gary Knutson, 840 W 17th, Suite 5, Bloomington, IN 47404. Paper submitted February 12, 1998; in revised form March 17, 1998; second revision July 10, 1998. b
Intervention: Comanagement of these cases was done with dental professionals. Chiropractic treatment included vectored/linear, upper cervical, high-velocity, low-amplitude chiropractic manipulation of the atlas vertebra, diversified manipulation, myofascial therapy, stretch and spray procedures, and soft tissue manual techniques. Conclusion: Temporomandibular joint dysfunction may cause cervical muscular and spinal biomechanical changes that may become visible and change on xray examination. Further investigation into this phenomenon is recommended. (J Manipulative Physiol Ther 1999;22:32-7) Key Indexing Terms: Temporomandibular Joint Dysfunction; Chiropractic Manipulation; Radiography; Dentistry
tion, researchers found that symptoms in the sternocleidomastoid and masseter muscles were correlated with parafunctional habits and body position.9 Another study found a relationship between occlusion and posture.10 By use of Michigan splint therapy in treating TMD, Cane et al11 found cervical pain and pain induced by epispinal or paraspinal pressure to be significantly reduced. The researchers concluded that “functional disturbances in the cervical vertebra could benefit from relaxation therapy acting upon the muscles of the mouth and jaw.” The preceding review outlines the correlation of TMD to signs and symptoms in the cervical spine, including alterations of cervical spine biomechanics that may be visible on x-ray examination.7,12 Chiropractic study of altered spinal biomechanics and the presence of bony misalignment through the use of x-ray examination is widespread, although the practice has been criticized.13 One such system of x-ray analysis is used to determine the position of the atlas as a result of joint dysfunction/chiropractic subluxation.14 The specific upper cervical x-ray procedure involves angular measurements of the atlas in the frontal (“X”) and transverse (“Y”) planes. Angular measurements, in degrees, are less prone to x-ray magnification errors than linear or millimetric measurements.15 The upper angle or atlas laterality is the acute angle formed by the intersection of the atlas plane line and a line drawn through the center of the skull— the center skull line. The atlas plane line is measured as “degrees off horizontal” on the side of the acute upper angle (Fig 1). Critical examination of specific upper cervical x-ray technique has demonstrated that the procedure and analysis is interexaminer and intraexaminer reliable.16-19
Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999 TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
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Table 1. Results of upper cervical x-ray studies
Upper angle Atlas plane angle
Film 1
Film 2
Film 3
Right 1⁄2 degrees High 1⁄2 degrees
Right 1⁄2 degrees 0
Left 3 degrees High 6 degrees
Critics suspect that the atlas positioning, as visualized with these types of x-ray studies, is due to random positional variation.20 However, preadjustment and postadjustment changes of atlas position have been examined and found not to be due to positioning or line-drawing errors,21 and atlas laterality has been found to be significantly correlated with the angular acceleration of the head and neck in motor vehicle accidents.22 These findings tend to rule out random positional variations as the cause of the changes in preatlaspostatlas mensuration. The ligaments in the upper cervical spine are lax, and movement of the atlas is due to muscular action.23 A hypothetical mechanism proposed for atlanto-occipital subluxation/joint dysfunction postulates a “nocifensive” reflex contraction of suboccipital muscles to account for the relative fixation and misalignment of the atlas in putative subluxation.24 Given this framework, a case can be made that the use of the specific upper cervical x-ray procedure and method of mensuration is an accurate determination of the relative position of the atlas because of activation of the surrounding musculature. Could TMD affect the upper cervical musculature and would any positional changes of the atlas be visible with this x-ray procedure? A second, more common, x-ray mensuration procedure used by chiropractors involves measuring the sagittal curve of the cervical spine. Despite what appears to be good reliability,25 the significance of cervical hypolordosis is the subject of much debate. Although some believe cervical hypolordosis to be a normal variant,26 others see it as a serious pathologic abnormality needing treatment.27 Farfan28 believes hypolordosis in the lumbar spine is caused by contraction of small, deep spinal erector muscles. Given the ability of TMD to cause cervical muscle tension,3,6,8,10-12 could such tension cause cervical hypolordosis noted on x-ray examination? A single case study has provided some evidence that this phenomenon can occur in a case of TMD,7 and treatment can effect a reversal of the cervical hypolordosis.
CASE REPORTS In the first case a patient had a chief complaint of severe headache often preceded by prodrome, nausea, occasional vomiting, and neck pain. Prior diagnosis was of “typical migraine.” A variety of treatments had been tried to cure or moderate the headaches, which were nearly constant. Current treatment consisted of heavy doses of meperidine (Demerol) and butorphanol (Stadol) administered approximately every 7 to 10 days.
Fig 1. Skull and atlas showing the central skull line and atlas plane line.
The patient demonstrated signs of upper cervical subluxation/joint dysfunction, motion palpation abnormalities, and postural distortion, including pelvic unleveling and functional leg length inequality. On the basis of these findings, a specific upper cervical x-ray study was done. Analysis showed excursion of the atlas in the frontal plane (laterality) of right 1⁄2 degree in relation to the skull, the atlas plane line high 1⁄2 degree on the right in relation to horizontal, and in the transverse plane (rotation) anterior 3 degrees (Fig 1). Vectored adjustment of the atlas on the basis of the x-ray findings provided significant symptomatic relief, including rapid relief of nausea and moderation of the severity and frequency of the migraine headaches. However, on occasion the patient would still complain of headache but without prodrome or nausea and with no objective signs that adjustment was necessary. It became apparent that the patient had two types of headaches, one with prodrome and nausea that responded quite well to adjustment and the other with no prodrome or nausea whose appearance was not correlated with signs of subluxation. A cause for this type of headache was sought. On the basis of complaints of tenderness and clicking in the left TMJ, the patient was sent for a dental evaluation. The eventual result was surgery on the left TMJ. Concerned that movement of the patient while under anesthesia may have irritated the C0/C1 joint dysfunction and altered the upper cervical misalignment pattern, another set of specific upper cervical x-rays films were taken (nasion and vertex). The results were nearly identical to the initial study, with slight right atlas laterality and rotation (Table 1). The patient’s course continued as before, with adjustment providing relief of the prodrome/nausea and headache but seemingly not related to the presumptive TMJ-caused headache. Complications from the TMJ surgery eventually caused severe inflammation of the TMJ, exacerbating the nonpro-
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Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999
TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
Fig 2. Pretreatment lateral cervical film.
Fig 3. Posttreatment (30 days later) lateral cervical film.
drome/nausea headaches. To get the inflammation under control, intra-articular injection of anti-inflammatory drugs was performed on the TMJ. The procedure resulted in severe headache and neck pain. When signs of subluxation/joint dysfunction and prodrome/nausea headache again appeared (4 months after surgery), a third upper cervical x-ray study was done. This new x-ray study found the atlas to be rotated in the frontal plane significantly to the left (3 degrees), with a plane line high 6 degrees (Table 1). The only intervening episode between the second and third upper cervical x-ray studies was the severe inflammation and pain in the left TMJ from the intra-articular injection. In the second case a patient had chronic hypomobility of mandibular opening, occasional dizziness, headache, neck pain with stiffness, and bilateral TMJ pain on palpation. These complaints were related to injuries from an automobile accident 9 years earlier. Immediately after the accident, the patient received medical care consisting of an extended course of physical therapy, supported by palliative use of muscle relaxants. The patient’s difficulties persisted, becoming chronic. The patient eventually consulted with her dentist regarding the jaw hypomobility and was referred for a chiropractic consultation. Examination findings revealed a mild postural mechanical spinal scoliosis, reduced cervical range of motion, and trigger points in the left trapezius, sternocleidomastoid, and external pterygoid muscles. Lateral cervical x-ray examina-
tion showed a straight cervical spine completely lacking lordosis (Fig 2). The initial diagnostic impressions included cervicocranial syndrome, TMJ dysfunction, and chronic myofascial pain with headache. The patient was then referred to an orthodontist who diagnosed a Class II, division I malocclusion with mandibular motion deviating left, and a right TMJ reciprocal early opening click. Dentally, the patient was treated with a mandibular orthopedic repositioning appliance (splint) and was instructed to wear the device for approximately 6 months. Chiropractic comanagement included myofascial therapy, stretch and spray procedures with fluorimethane, hot pack fomentation, and soft tissue manual techniques as adjuncts to cervical spinal manipulation. This intervention helped to reduce cranial and cervical pain of myofascial origin. The patient had presented with a spinal postural imbalance of a left short leg, confirmed by orthoscanogram x-ray study, and was thus fitted with a 3-mm heel lift support. Dietary management included recommendations to avoid foods that require prolonged chewing, such as meat, candy, or gum. Mandibular exercises and cervical stretches were prescribed. At the conclusion of the chiropractic management, the patient was fitted with restorative orthodontic braces. The patient responded favorably to interdisciplinary TMD management, with the intensity and frequency of cervical spine muscle pain and headaches significantly improved. An x-ray film (Fig 3) was taken at 30 days and revealed a cervi-
Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999 TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
cal lordosis with weight bearing now at the base of C3; normal is at the C4/C5 disk.29 This x-ray film was taken with the orthopedic appliance in place.
DISCUSSION The trigeminal nerve is the largest of the cranial nerves; one of its functions is to convey proprioceptive information from the extraocular muscles.30,31 It has long been held that these ocular muscle signals are transmitted by way of the spinal tract of the trigeminal nerve to the cervical muscles that control head movement.30-32 The trigeminal system has been found to connect with the gray matter in the upper cervical cord (C1 and C2) and appears to be widespread in terms of both sensory and motor reflex activity.33 Experimentation has shown that electrical stimulation of the infraorbital nerve, a branch of the trigeminal nerve, activates interneurons in the ventral horns of C1 to C4, readily exciting neck muscle motoneurons.34-36 Bogduk37 calls the continuation of the gray matter of the spinal tract of the trigeminal nerve and the dorsal horns of the upper 3 cervical spinal cord segments the trigeminocervical nucleus. He writes, “As such, the trigeminocervical nucleus is the essential nociceptive nucleus of the upper neck, head and throat. Whatever the actual innervation of structures in this region, noxious stimuli from them will be mediated by the trigeminocervical nucleus.” Transmission of TMD nociception by means of the auriculotemporal nerve, the posterior trunk of the mandibular nerve, to the spinal tract of the trigeminal nerve, the trigeminocervical nucleus, and the motoneurons of the cervical spine is the probable mechanism by which TMD causes cervical pain and muscle tension changes.3,6-12 In the first case it appears that this patient had two superimposed problems, right side C0/C1 joint dysfunction (chiropractic subluxation), causing prodrome/nausea headache, and left side TMD, causing headache without these symptoms. The establishment of atlas subluxation/joint dysfunction as a stable radiographic entity is precluded by the dangers of ionizing radiation. However, one case study38 has demonstrated such stability during cervical rotation and another study39 has shown that an upper cervical x-ray listing, barring trauma, tends to remain static over long periods of time. In this case the x-ray film demonstrated atlas misalignment was static at right-level for two studies, then made a dramatic change to left-high. The only notable event during this time was the severe inflammatory reaction in the left TMJ. Inflammation is known to lower the threshold for nociception such that normal joint motion can stimulate nociceptive output.40 Muscles move bones; the atlas is moved by muscles,23 and irritation of the trigeminal nerve has been shown to cause contraction of upper cervical muscles.33-36 Without a noninvasive method to determine atlas position, it cannot be known to what degree, if any, TMD or any nocicieptive signal carried by the trigeminal nerve can affect atlas position. The explanation proposed here is that the inflamed, nociceptive left TMJ caused reflex contraction of the upper cervical musculature, resulting in the shifting
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positions of the atlas noted on the x-ray studies. Another explanation for the changes seen on the x-ray studies are differences in patient placement between the second and third x-ray studies. Although such an alternative hypothesis is possible, upper cervical subluxation x-ray misalignment has been shown to be stable for side of atlas laterality and rotation.39 Such a drastic change in the atlas position on x-ray examination would likely have required an alteration of patient position on the x-ray setup so gross that the film would either not have been taken or thrown out for general lack of precision. To the extent that the nociception/muscle contraction hypothesis is correct, this case provides tentative evidence that such TMD-induced cervical muscular contraction may cause misalignment of the atlas as seen on specific upper cervical x-ray films. Such misalignment and relative fixation might easily be misconstrued by the clinician as evidence of atlas subluxation, and treatment might be begun erroneously on the basis of those findings if the possibility of TMD is not examined. This case also illustrates that a patient may have headaches of different types for different reasons, including from TMD, and it is incumbent on the doctor to seek and treat the causes. Interestingly, although TMD may cause atlas misalignment as viewed on x-ray study, atlas subluxation/joint dysfunction may cause TMD. It has been theorized that atlantooccipital joint dysfunction/subluxation causes pathologic activation of the tonic neck reflexes.24 A single case study of C0/C1 intra-articular joint block injection showed significant changes in postural distortion most likely caused by moderation of pathologic asymmetric tonic neck reflexes.41 Tonic neck reflexes have been shown to have a significant influence on the temporalis muscle,42 an elevator of the jaw. In addition, a closely organized relationship appears to exist between tonic neck reflex activity and trigeminal reflex activity.43 Although admittedly speculative, it is within the realm of possibility that C0/C1 joint dysfunction causing pathologic activation of asymmetric tonic neck reflexes could affect the temporalis muscle and, in turn, the TMJ. The possibility of atlas subluxation/joint dysfunction as a cause of TMD should be explored. The global postural distortion noted with pathologic stimulation of asymmetric tonic neck reflexes44-46 may also help explain the connection of TMD and lumbosacral pain and x-ray findings noted in the case study by Chinappi and Getzoff.47 In the second case it appears that the chronic TMD (traumatic in origin) that was correlated with neck pain and headache developed in the patient. X-ray studies confirmed cervical spine hypolordosis. Comanagement use of the TMJ splint with osseous and soft tissue manipulative techniques brought about a normalization of the cervical lordosis in 30 days. Chinappi48 postulates that the loss of cervical lordosis is the result of unilateral TMJ fixation, causing flexion of the head through the suprahyoid and infrahyoid muscles. Others postulate that nociceptive irritation of the TMD is transmit-
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Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999
TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
ted by the trigeminal nerve to the trigeminocervical nucleus and the cervical erector muscles.30 As Farfan28 has theorized, this erector spinae muscle tension may lead to hypolordosis. If the source of the trigeminal nociceptive irritation is dealt with, a return to normal lordosis may occur, as was seen here. Because treatment involved both manipulation of the cervical spine and soft tissue TMJ work, it cannot be known for certain whether one particular modality was responsible for moderating the cervical hypolordosis. Still, the results show quite a dramatic change of a chronic condition in only 30 days. These results, in which long-term physical therapy had failed, point to the need for this sort of patient comanagement when appropriate. These two case study scenarios are important because the alteration of normal atlas positioning and/or cervical curvature seen on the x-ray examination is most often taken by chiropractors to be signs of vertebral joint dysfunction/subluxation and not TMJ dysfunction. In cases in which TMD is suspected, a competent evaluation should be sought.
CONCLUSION TMJ dysfunction is a complex series of disorders often caused by trauma and characterized by cervical musculoskeletal symptoms. These two case reports provide tentative evidence that changes in x-ray examinations, as used by chiropractors, may be correlated with a diagnosis of TMD. If TMD is suspected, the clinician should be cautious and not necessarily attribute the cause of the biomechanical changes noted on x-ray examination entirely to vertebral subluxation. A prudent course would be assessment and cotreatment of the TMJ disorder and associated musculoskeletal dysfunction. Further study to better examine the relationship between TMD and alterations in the findings of x-ray studies used by chiropractors is recommended.
REFERENCES 1. Abdel-Fatah R. Evaluating temporomandibular joint injuries. 2nd ed. New York: Wiley; 1998. p. 2, 121, 115. 2. Travel J. Myofascial pain and dysfunction, the trigger point manual. Vol 1. Baltimore: Williams & Wilkins; 1983. p. 171. 3. Steigerwald D, Croft A, et al. Whiplash and temporomandibular disorders. San Diego: Keiser Publishing; 1992. p. 14-5. 4. Lader E. Whiplash and related cervical trauma. New York: The Jamaica Hospital TMJ Department (undated pamphlet). 5. Mintz V. Diseases of the temporomandibular apparatus. 2nd ed. In: Morgan DH, House LR, Hall WP, Vamyas SJ, editors. St Louis: Mosby; 1982. p. 232. 6. Roccabado M. Diagnosis and treatment of abnormal cervicocranial and craniomandibular mechanics. In: Solberg WK, Clark GT. Abnormal jaw mechanic diagnosis and treatment. Chicago: Quintessence; 1984. p. 164. 7. Chinappi AS, Getzoff H. The dental-chiropractic co-treatment of structural disorders of the jaw and temporomandibular joint dysfunction. J Manipulative Physiol Ther 1995;18:476-81. 8. Padamsee M, Mehtan N, Forgione A, Bansal S. Incidence of cervical disorders in a TMD population [IADR; Abstract No 680]. J Dent Res 1994;73. 9. Palazzi C, Miralles R, Soto MA, Santander H, Zuniga C, Moya H. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in patients with myogenic craniocervical-mandibular Dysfunction. Cranio 1996;14:200-9.
10. Nobili A, Adversi R. Relationship between posture and occlusion: a clinical and experimental investigation. Cranio 1996;14:274-85. 11. Cane L, Schieroni MP, Ribero G, Ferrero M, Carossa S. Effectiveness of the Michigan splint in reducing functional cervical disturbances: a preliminary study. Cranio 1997;15:132-5. 12. Mannheimer JS, Rosenthal RM. Acute and chronic postural abnormalities as related to craniofascial pain and temporomandibular disorders. Dent Clin North Am 1991;35:185-208. 13. Harger BL, Taylor JAM, Haas M, Nyiendo J. Chiropractic radiologists: a survey of chiropractor’s attitudes and patterns of use. J Manipulative Physiol Ther 1997;20:311-4. 14. Grostic JD. Grostic procedure notes. Marietta (GA): Author; 1985. 15. Owens E. Line drawing analysis of static cervical x-ray used on chiropractic. J Manipulative Physiol Ther 1992;15:442-9. 16. Seemann DC. Observer reliability and objectivity using rotatory measurements on x-rays. Upper Cervical Monogr 1986;4:1, 68. 17. Jackson BL, Barker W, Bentz J, Gambale AG. Inter and intraexaminer reliability of the upper cervical x-ray marking system: a second look. J Manipulative Physiol Ther 1987;10:157-63. 18. Rochester RP. Inter and intra-examiner reliability of the upper cervical x-ray marking system: a third and expanded look. Chiropr Res J 1994;3:23-31. 19. Seemann DC. A reliability study using a positive nasium to establish laterality. Upper Cervical Monogr 1994;5:7-8. 20. Sigler D, Howe J. Inter- and intra-examiner reliability of the upper cervical marking system. J Manipulative Physiol Ther 1985;8:75-80. 21. Rochester RP, Owens EO. Patient placement error in rotation and its effect on the upper cervical measuring system. Chiropract Res J 1996;3:40-53. 22. Knutson G. Atlas laterality/laterality and rotation and the angular acceleration of the head and neck in motor vehicle accident. Chiropract Res J 1996;3:11-9. 23. Goel VK, Clark CR, Gallaes K, King Liu Y. Moment-rotation relationships of the ligamentous occipito-atlanto-axial complex. J Biomech 1988;21:673-80. 24. Knutson G. Tonic neck reflexes, leg length inequality and atlanto-occipital fat pad impingement: an atlas subluxation complex hypothesis. Chiropr Res J 1997;IV:64-76. 25. Cote P, Cassidy DJ. Apophyseal joint degeneration, disc degeneration, and sagittal curve of the cervical spine: Can they be measured reliably on radiographs? Spine 1997;22:859-64. 26. Gore DR, Sepic SB, Gardner GM. Roentgenographic findings of the cervical spine in asymptomatic people. Spine 1986; 6:521-4. 27. Harrison DD, Troyanovich SJ, Harrison DE, Janik TJ, Murphy DJ. A normal sagittal spinal configuration: a desirable clinical outcome. J Manipulative Physiol Ther 1996;19:398-405. 28. Farfan HF. Mechanical disorders of the low back. Philadelphia: Lea & Febiger; 1973. p. 181-2. 29. Yochum T, Rowe L. Essentials of skeletal radiology. Vol 1. Baltimore: Williams & Wilkins; 1987. p. 182. 30. Manni E, Giovanni P, Rolando M, Pettorossi VE. Trigeminal influences on extensor muscles on the neck. Exp Neurol 1975;47:330-42. 31. Green JD, DeGroot J, Sutin J. Trigemino-bulbar reflex pathways. Am J Physiol 1957;189:384-8. 32. Abrahams VC. The physiology of neck muscles: their role in head movement and maintenance of posture. Can J Physiol 1977;55:332-8. 33. Kerr FW, Olafson RA. Trigeminal and cervical volleys. Arch Neurol 1961;5:69-76. 34. Abrahams VC, Anstee G, Richmond FJR. Further studies on the organization of the upper cervical cord. Proc Can Fed Biol Soc 1976;19:146.
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35. Alstermark B, Pinter MJ, Sasaki S, Tantisria B. Trigeminal excitation of dorsal neck motoneurons in the cat. Exp Brain Res 1992;92:183-93. 36. DiLazzaro V, Quartarone A, Higuchi K, Rothwell JC. Shortterm latency trigemino-cervical reflexes in man. Exp Brain Res 1995;102:474-82. 37. Bogduk N. The anatomical basis for cervicogenic headache. J Manipulative Physiol Ther 1992;15:67-70. 38. Hart J. Effect of patient positioning on an upper cervical x-ray listing: a case study. J Chiropract Res 1988:(Autumn) 19-21. 39. Palmer T, Denton K, Palmer J. A clinical investigation into upper-cervical biomechanical stability: part 1. Upper Cervical Monogr 1990;4(10):2-7. 40. Coggeshall RE, Hong KA, Langford LA, Schaible HG, Schmidt RF. Discharge characteristics of the fine medial articular afferents at rest and during passive movements of inflamed knee joints. Brain Res 1983;272(1):185-8. 41. Knutson G. Moderation of postural distortion following upper cervical facet joint block injection: a case study. Chiropract Res J 1998;5:28-34.
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42. Macaluso GM, De Laat AD, Pavesi G. The influence of the asymmetric tonic neck reflex on the H-reflex in human temporal muscle. Minerva Stomatol 1996;45:387-92. 43. Ormeno G, Miralles R, Santander H, Casassus R, Ferrer P, Palazzi C, et al. Body position effects on sternocleidomastoid and masseter EMG pattern activity in patients undergoing occlusal splint therapy. J Craniomandib Pract 1997;15:300-9. 44. Hellebrandt FA, Schade M, Carns M. Methods of evoking the tonic neck reflexes in normal humans subjects. Am J Phys Med 1962;41:90-135. 45. Connolly BH, Michael BT. Early detection of scoliosis: a neurologic approach using the asymmetrical tonic neck reflex. Phys Ther 1984;64:304-7. 46. Marinelli PV. The asymmetric tonic neck reflex: its presence and significance in the newborn. Clin Pediatr 1983;22:544-6. 47. Chinappi AS, Getzoff H. Chiropractic/dental cotreatment of lumbosacral pain with temporomandibular joint involvement. J Manipulative Physiol Ther 1996;19:607-12. 48. Chinappi AS. A new management model for treating structuralbased disorders: dental orthopedic and chiropractic co-treatment. J Manipulative Physiol Ther 1994;17:614-9.
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CASE REPORTS Possible Manifestation of Temporomandibular Joint Dysfunction on Chiropractic Cervical X-ray Studies Gary A. Knutson, DC,a and Moses Jacob, DC b
ABSTRACT Objective: Our purpose was to show that biomechanical alterations toward and away from normal on x-ray studies may be the result of changes in temporomandibular joint dysfunction and to discuss possible neurologic explanations for this phenomenon. Clinical Features: Two patients are discussed; the first had migraine headache symptoms, and the second had chronic hypomobility of mandibular opening, dizziness, headache, and neck pain and stiffness. In both patients mensuration changes in different types of cervical x-ray studies were noted in conjunction with exacerbation of, and elimination of, temporomandibular joint dysfunction.
INTRODUCTION Temporomandibular joint dysfunction (TMD) is the general term used for any disorder that affects the temporomandibular joint (TMJ). The cause of TMD is considered to be multifactorial and has been attributed to occlusal disorders; bruxism; thermal, chemical, or electrical causes1; and psychogenic/emotional factors.2 Some of the most common causative factors are trauma (both microtrauma and macrotrauma) and iatrogenic (excessive mouth opening during dental procedures or surgical anesthetic intubation and faulty cervical traction). A major traumatic cause of TMD is a hyperextensionhyperflexion injury during motor vehicle accidents.1 Numerous authors have detailed the mechanics of TMD as a direct or secondary result of traumatic “whiplash” injury.1,3,4 Symptoms of TMD disorders include facial or neck pain, headaches, and TMJ noises, including popping, clicking, and crepitation. Other symptoms associated with TMD include tinnitus, vertigo, and referred pain in the preauricular, frontal, and retro-orbital areas, as well as numbness of the fingers.5 The correlation of TMD with cervical spine disorders has been detailed by several authors,3,6,7 including one study that demonstrated a 70% cervical spine dysfunction in a patient population with TMD.8 By use of electromyelography in patients with myogenic craniocervical mandibular dysfunca
Private practice of chiropractic, Bloomington, Indiana. Private practice of chiropractic, Novato, California. Submit requests for reprints to: Dr Gary Knutson, 840 W 17th, Suite 5, Bloomington, IN 47404. Paper submitted February 12, 1998; in revised form March 17, 1998; second revision July 10, 1998. b
Intervention: Comanagement of these cases was done with dental professionals. Chiropractic treatment included vectored/linear, upper cervical, high-velocity, low-amplitude chiropractic manipulation of the atlas vertebra, diversified manipulation, myofascial therapy, stretch and spray procedures, and soft tissue manual techniques. Conclusion: Temporomandibular joint dysfunction may cause cervical muscular and spinal biomechanical changes that may become visible and change on xray examination. Further investigation into this phenomenon is recommended. (J Manipulative Physiol Ther 1999;22:32-7) Key Indexing Terms: Temporomandibular Joint Dysfunction; Chiropractic Manipulation; Radiography; Dentistry
tion, researchers found that symptoms in the sternocleidomastoid and masseter muscles were correlated with parafunctional habits and body position.9 Another study found a relationship between occlusion and posture.10 By use of Michigan splint therapy in treating TMD, Cane et al11 found cervical pain and pain induced by epispinal or paraspinal pressure to be significantly reduced. The researchers concluded that “functional disturbances in the cervical vertebra could benefit from relaxation therapy acting upon the muscles of the mouth and jaw.” The preceding review outlines the correlation of TMD to signs and symptoms in the cervical spine, including alterations of cervical spine biomechanics that may be visible on x-ray examination.7,12 Chiropractic study of altered spinal biomechanics and the presence of bony misalignment through the use of x-ray examination is widespread, although the practice has been criticized.13 One such system of x-ray analysis is used to determine the position of the atlas as a result of joint dysfunction/chiropractic subluxation.14 The specific upper cervical x-ray procedure involves angular measurements of the atlas in the frontal (“X”) and transverse (“Y”) planes. Angular measurements, in degrees, are less prone to x-ray magnification errors than linear or millimetric measurements.15 The upper angle or atlas laterality is the acute angle formed by the intersection of the atlas plane line and a line drawn through the center of the skull— the center skull line. The atlas plane line is measured as “degrees off horizontal” on the side of the acute upper angle (Fig 1). Critical examination of specific upper cervical x-ray technique has demonstrated that the procedure and analysis is interexaminer and intraexaminer reliable.16-19
Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999 TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
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Table 1. Results of upper cervical x-ray studies
Upper angle Atlas plane angle
Film 1
Film 2
Film 3
Right 1⁄2 degrees High 1⁄2 degrees
Right 1⁄2 degrees 0
Left 3 degrees High 6 degrees
Critics suspect that the atlas positioning, as visualized with these types of x-ray studies, is due to random positional variation.20 However, preadjustment and postadjustment changes of atlas position have been examined and found not to be due to positioning or line-drawing errors,21 and atlas laterality has been found to be significantly correlated with the angular acceleration of the head and neck in motor vehicle accidents.22 These findings tend to rule out random positional variations as the cause of the changes in preatlaspostatlas mensuration. The ligaments in the upper cervical spine are lax, and movement of the atlas is due to muscular action.23 A hypothetical mechanism proposed for atlanto-occipital subluxation/joint dysfunction postulates a “nocifensive” reflex contraction of suboccipital muscles to account for the relative fixation and misalignment of the atlas in putative subluxation.24 Given this framework, a case can be made that the use of the specific upper cervical x-ray procedure and method of mensuration is an accurate determination of the relative position of the atlas because of activation of the surrounding musculature. Could TMD affect the upper cervical musculature and would any positional changes of the atlas be visible with this x-ray procedure? A second, more common, x-ray mensuration procedure used by chiropractors involves measuring the sagittal curve of the cervical spine. Despite what appears to be good reliability,25 the significance of cervical hypolordosis is the subject of much debate. Although some believe cervical hypolordosis to be a normal variant,26 others see it as a serious pathologic abnormality needing treatment.27 Farfan28 believes hypolordosis in the lumbar spine is caused by contraction of small, deep spinal erector muscles. Given the ability of TMD to cause cervical muscle tension,3,6,8,10-12 could such tension cause cervical hypolordosis noted on x-ray examination? A single case study has provided some evidence that this phenomenon can occur in a case of TMD,7 and treatment can effect a reversal of the cervical hypolordosis.
CASE REPORTS In the first case a patient had a chief complaint of severe headache often preceded by prodrome, nausea, occasional vomiting, and neck pain. Prior diagnosis was of “typical migraine.” A variety of treatments had been tried to cure or moderate the headaches, which were nearly constant. Current treatment consisted of heavy doses of meperidine (Demerol) and butorphanol (Stadol) administered approximately every 7 to 10 days.
Fig 1. Skull and atlas showing the central skull line and atlas plane line.
The patient demonstrated signs of upper cervical subluxation/joint dysfunction, motion palpation abnormalities, and postural distortion, including pelvic unleveling and functional leg length inequality. On the basis of these findings, a specific upper cervical x-ray study was done. Analysis showed excursion of the atlas in the frontal plane (laterality) of right 1⁄2 degree in relation to the skull, the atlas plane line high 1⁄2 degree on the right in relation to horizontal, and in the transverse plane (rotation) anterior 3 degrees (Fig 1). Vectored adjustment of the atlas on the basis of the x-ray findings provided significant symptomatic relief, including rapid relief of nausea and moderation of the severity and frequency of the migraine headaches. However, on occasion the patient would still complain of headache but without prodrome or nausea and with no objective signs that adjustment was necessary. It became apparent that the patient had two types of headaches, one with prodrome and nausea that responded quite well to adjustment and the other with no prodrome or nausea whose appearance was not correlated with signs of subluxation. A cause for this type of headache was sought. On the basis of complaints of tenderness and clicking in the left TMJ, the patient was sent for a dental evaluation. The eventual result was surgery on the left TMJ. Concerned that movement of the patient while under anesthesia may have irritated the C0/C1 joint dysfunction and altered the upper cervical misalignment pattern, another set of specific upper cervical x-rays films were taken (nasion and vertex). The results were nearly identical to the initial study, with slight right atlas laterality and rotation (Table 1). The patient’s course continued as before, with adjustment providing relief of the prodrome/nausea and headache but seemingly not related to the presumptive TMJ-caused headache. Complications from the TMJ surgery eventually caused severe inflammation of the TMJ, exacerbating the nonpro-
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Fig 2. Pretreatment lateral cervical film.
Fig 3. Posttreatment (30 days later) lateral cervical film.
drome/nausea headaches. To get the inflammation under control, intra-articular injection of anti-inflammatory drugs was performed on the TMJ. The procedure resulted in severe headache and neck pain. When signs of subluxation/joint dysfunction and prodrome/nausea headache again appeared (4 months after surgery), a third upper cervical x-ray study was done. This new x-ray study found the atlas to be rotated in the frontal plane significantly to the left (3 degrees), with a plane line high 6 degrees (Table 1). The only intervening episode between the second and third upper cervical x-ray studies was the severe inflammation and pain in the left TMJ from the intra-articular injection. In the second case a patient had chronic hypomobility of mandibular opening, occasional dizziness, headache, neck pain with stiffness, and bilateral TMJ pain on palpation. These complaints were related to injuries from an automobile accident 9 years earlier. Immediately after the accident, the patient received medical care consisting of an extended course of physical therapy, supported by palliative use of muscle relaxants. The patient’s difficulties persisted, becoming chronic. The patient eventually consulted with her dentist regarding the jaw hypomobility and was referred for a chiropractic consultation. Examination findings revealed a mild postural mechanical spinal scoliosis, reduced cervical range of motion, and trigger points in the left trapezius, sternocleidomastoid, and external pterygoid muscles. Lateral cervical x-ray examina-
tion showed a straight cervical spine completely lacking lordosis (Fig 2). The initial diagnostic impressions included cervicocranial syndrome, TMJ dysfunction, and chronic myofascial pain with headache. The patient was then referred to an orthodontist who diagnosed a Class II, division I malocclusion with mandibular motion deviating left, and a right TMJ reciprocal early opening click. Dentally, the patient was treated with a mandibular orthopedic repositioning appliance (splint) and was instructed to wear the device for approximately 6 months. Chiropractic comanagement included myofascial therapy, stretch and spray procedures with fluorimethane, hot pack fomentation, and soft tissue manual techniques as adjuncts to cervical spinal manipulation. This intervention helped to reduce cranial and cervical pain of myofascial origin. The patient had presented with a spinal postural imbalance of a left short leg, confirmed by orthoscanogram x-ray study, and was thus fitted with a 3-mm heel lift support. Dietary management included recommendations to avoid foods that require prolonged chewing, such as meat, candy, or gum. Mandibular exercises and cervical stretches were prescribed. At the conclusion of the chiropractic management, the patient was fitted with restorative orthodontic braces. The patient responded favorably to interdisciplinary TMD management, with the intensity and frequency of cervical spine muscle pain and headaches significantly improved. An x-ray film (Fig 3) was taken at 30 days and revealed a cervi-
Journal of Manipulative and Physiological Therapeutics Volume 22 • Number 1 • January 1999 TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
cal lordosis with weight bearing now at the base of C3; normal is at the C4/C5 disk.29 This x-ray film was taken with the orthopedic appliance in place.
DISCUSSION The trigeminal nerve is the largest of the cranial nerves; one of its functions is to convey proprioceptive information from the extraocular muscles.30,31 It has long been held that these ocular muscle signals are transmitted by way of the spinal tract of the trigeminal nerve to the cervical muscles that control head movement.30-32 The trigeminal system has been found to connect with the gray matter in the upper cervical cord (C1 and C2) and appears to be widespread in terms of both sensory and motor reflex activity.33 Experimentation has shown that electrical stimulation of the infraorbital nerve, a branch of the trigeminal nerve, activates interneurons in the ventral horns of C1 to C4, readily exciting neck muscle motoneurons.34-36 Bogduk37 calls the continuation of the gray matter of the spinal tract of the trigeminal nerve and the dorsal horns of the upper 3 cervical spinal cord segments the trigeminocervical nucleus. He writes, “As such, the trigeminocervical nucleus is the essential nociceptive nucleus of the upper neck, head and throat. Whatever the actual innervation of structures in this region, noxious stimuli from them will be mediated by the trigeminocervical nucleus.” Transmission of TMD nociception by means of the auriculotemporal nerve, the posterior trunk of the mandibular nerve, to the spinal tract of the trigeminal nerve, the trigeminocervical nucleus, and the motoneurons of the cervical spine is the probable mechanism by which TMD causes cervical pain and muscle tension changes.3,6-12 In the first case it appears that this patient had two superimposed problems, right side C0/C1 joint dysfunction (chiropractic subluxation), causing prodrome/nausea headache, and left side TMD, causing headache without these symptoms. The establishment of atlas subluxation/joint dysfunction as a stable radiographic entity is precluded by the dangers of ionizing radiation. However, one case study38 has demonstrated such stability during cervical rotation and another study39 has shown that an upper cervical x-ray listing, barring trauma, tends to remain static over long periods of time. In this case the x-ray film demonstrated atlas misalignment was static at right-level for two studies, then made a dramatic change to left-high. The only notable event during this time was the severe inflammatory reaction in the left TMJ. Inflammation is known to lower the threshold for nociception such that normal joint motion can stimulate nociceptive output.40 Muscles move bones; the atlas is moved by muscles,23 and irritation of the trigeminal nerve has been shown to cause contraction of upper cervical muscles.33-36 Without a noninvasive method to determine atlas position, it cannot be known to what degree, if any, TMD or any nocicieptive signal carried by the trigeminal nerve can affect atlas position. The explanation proposed here is that the inflamed, nociceptive left TMJ caused reflex contraction of the upper cervical musculature, resulting in the shifting
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positions of the atlas noted on the x-ray studies. Another explanation for the changes seen on the x-ray studies are differences in patient placement between the second and third x-ray studies. Although such an alternative hypothesis is possible, upper cervical subluxation x-ray misalignment has been shown to be stable for side of atlas laterality and rotation.39 Such a drastic change in the atlas position on x-ray examination would likely have required an alteration of patient position on the x-ray setup so gross that the film would either not have been taken or thrown out for general lack of precision. To the extent that the nociception/muscle contraction hypothesis is correct, this case provides tentative evidence that such TMD-induced cervical muscular contraction may cause misalignment of the atlas as seen on specific upper cervical x-ray films. Such misalignment and relative fixation might easily be misconstrued by the clinician as evidence of atlas subluxation, and treatment might be begun erroneously on the basis of those findings if the possibility of TMD is not examined. This case also illustrates that a patient may have headaches of different types for different reasons, including from TMD, and it is incumbent on the doctor to seek and treat the causes. Interestingly, although TMD may cause atlas misalignment as viewed on x-ray study, atlas subluxation/joint dysfunction may cause TMD. It has been theorized that atlantooccipital joint dysfunction/subluxation causes pathologic activation of the tonic neck reflexes.24 A single case study of C0/C1 intra-articular joint block injection showed significant changes in postural distortion most likely caused by moderation of pathologic asymmetric tonic neck reflexes.41 Tonic neck reflexes have been shown to have a significant influence on the temporalis muscle,42 an elevator of the jaw. In addition, a closely organized relationship appears to exist between tonic neck reflex activity and trigeminal reflex activity.43 Although admittedly speculative, it is within the realm of possibility that C0/C1 joint dysfunction causing pathologic activation of asymmetric tonic neck reflexes could affect the temporalis muscle and, in turn, the TMJ. The possibility of atlas subluxation/joint dysfunction as a cause of TMD should be explored. The global postural distortion noted with pathologic stimulation of asymmetric tonic neck reflexes44-46 may also help explain the connection of TMD and lumbosacral pain and x-ray findings noted in the case study by Chinappi and Getzoff.47 In the second case it appears that the chronic TMD (traumatic in origin) that was correlated with neck pain and headache developed in the patient. X-ray studies confirmed cervical spine hypolordosis. Comanagement use of the TMJ splint with osseous and soft tissue manipulative techniques brought about a normalization of the cervical lordosis in 30 days. Chinappi48 postulates that the loss of cervical lordosis is the result of unilateral TMJ fixation, causing flexion of the head through the suprahyoid and infrahyoid muscles. Others postulate that nociceptive irritation of the TMD is transmit-
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TMJ Dysfunction on Chiropractic Cervical X-ray Studies • Knutson and Jacob
ted by the trigeminal nerve to the trigeminocervical nucleus and the cervical erector muscles.30 As Farfan28 has theorized, this erector spinae muscle tension may lead to hypolordosis. If the source of the trigeminal nociceptive irritation is dealt with, a return to normal lordosis may occur, as was seen here. Because treatment involved both manipulation of the cervical spine and soft tissue TMJ work, it cannot be known for certain whether one particular modality was responsible for moderating the cervical hypolordosis. Still, the results show quite a dramatic change of a chronic condition in only 30 days. These results, in which long-term physical therapy had failed, point to the need for this sort of patient comanagement when appropriate. These two case study scenarios are important because the alteration of normal atlas positioning and/or cervical curvature seen on the x-ray examination is most often taken by chiropractors to be signs of vertebral joint dysfunction/subluxation and not TMJ dysfunction. In cases in which TMD is suspected, a competent evaluation should be sought.
CONCLUSION TMJ dysfunction is a complex series of disorders often caused by trauma and characterized by cervical musculoskeletal symptoms. These two case reports provide tentative evidence that changes in x-ray examinations, as used by chiropractors, may be correlated with a diagnosis of TMD. If TMD is suspected, the clinician should be cautious and not necessarily attribute the cause of the biomechanical changes noted on x-ray examination entirely to vertebral subluxation. A prudent course would be assessment and cotreatment of the TMJ disorder and associated musculoskeletal dysfunction. Further study to better examine the relationship between TMD and alterations in the findings of x-ray studies used by chiropractors is recommended.
REFERENCES 1. Abdel-Fatah R. Evaluating temporomandibular joint injuries. 2nd ed. New York: Wiley; 1998. p. 2, 121, 115. 2. Travel J. Myofascial pain and dysfunction, the trigger point manual. Vol 1. Baltimore: Williams & Wilkins; 1983. p. 171. 3. Steigerwald D, Croft A, et al. Whiplash and temporomandibular disorders. San Diego: Keiser Publishing; 1992. p. 14-5. 4. Lader E. Whiplash and related cervical trauma. New York: The Jamaica Hospital TMJ Department (undated pamphlet). 5. Mintz V. Diseases of the temporomandibular apparatus. 2nd ed. In: Morgan DH, House LR, Hall WP, Vamyas SJ, editors. St Louis: Mosby; 1982. p. 232. 6. Roccabado M. Diagnosis and treatment of abnormal cervicocranial and craniomandibular mechanics. In: Solberg WK, Clark GT. Abnormal jaw mechanic diagnosis and treatment. Chicago: Quintessence; 1984. p. 164. 7. Chinappi AS, Getzoff H. The dental-chiropractic co-treatment of structural disorders of the jaw and temporomandibular joint dysfunction. J Manipulative Physiol Ther 1995;18:476-81. 8. Padamsee M, Mehtan N, Forgione A, Bansal S. Incidence of cervical disorders in a TMD population [IADR; Abstract No 680]. J Dent Res 1994;73. 9. Palazzi C, Miralles R, Soto MA, Santander H, Zuniga C, Moya H. Body position effects on EMG activity of sternocleidomastoid and masseter muscles in patients with myogenic craniocervical-mandibular Dysfunction. Cranio 1996;14:200-9.
10. Nobili A, Adversi R. Relationship between posture and occlusion: a clinical and experimental investigation. Cranio 1996;14:274-85. 11. Cane L, Schieroni MP, Ribero G, Ferrero M, Carossa S. Effectiveness of the Michigan splint in reducing functional cervical disturbances: a preliminary study. Cranio 1997;15:132-5. 12. Mannheimer JS, Rosenthal RM. Acute and chronic postural abnormalities as related to craniofascial pain and temporomandibular disorders. Dent Clin North Am 1991;35:185-208. 13. Harger BL, Taylor JAM, Haas M, Nyiendo J. Chiropractic radiologists: a survey of chiropractor’s attitudes and patterns of use. J Manipulative Physiol Ther 1997;20:311-4. 14. Grostic JD. Grostic procedure notes. Marietta (GA): Author; 1985. 15. Owens E. Line drawing analysis of static cervical x-ray used on chiropractic. J Manipulative Physiol Ther 1992;15:442-9. 16. Seemann DC. Observer reliability and objectivity using rotatory measurements on x-rays. Upper Cervical Monogr 1986;4:1, 68. 17. Jackson BL, Barker W, Bentz J, Gambale AG. Inter and intraexaminer reliability of the upper cervical x-ray marking system: a second look. J Manipulative Physiol Ther 1987;10:157-63. 18. Rochester RP. Inter and intra-examiner reliability of the upper cervical x-ray marking system: a third and expanded look. Chiropr Res J 1994;3:23-31. 19. Seemann DC. A reliability study using a positive nasium to establish laterality. Upper Cervical Monogr 1994;5:7-8. 20. Sigler D, Howe J. Inter- and intra-examiner reliability of the upper cervical marking system. J Manipulative Physiol Ther 1985;8:75-80. 21. Rochester RP, Owens EO. Patient placement error in rotation and its effect on the upper cervical measuring system. Chiropract Res J 1996;3:40-53. 22. Knutson G. Atlas laterality/laterality and rotation and the angular acceleration of the head and neck in motor vehicle accident. Chiropract Res J 1996;3:11-9. 23. Goel VK, Clark CR, Gallaes K, King Liu Y. Moment-rotation relationships of the ligamentous occipito-atlanto-axial complex. J Biomech 1988;21:673-80. 24. Knutson G. Tonic neck reflexes, leg length inequality and atlanto-occipital fat pad impingement: an atlas subluxation complex hypothesis. Chiropr Res J 1997;IV:64-76. 25. Cote P, Cassidy DJ. Apophyseal joint degeneration, disc degeneration, and sagittal curve of the cervical spine: Can they be measured reliably on radiographs? Spine 1997;22:859-64. 26. Gore DR, Sepic SB, Gardner GM. Roentgenographic findings of the cervical spine in asymptomatic people. Spine 1986; 6:521-4. 27. Harrison DD, Troyanovich SJ, Harrison DE, Janik TJ, Murphy DJ. A normal sagittal spinal configuration: a desirable clinical outcome. J Manipulative Physiol Ther 1996;19:398-405. 28. Farfan HF. Mechanical disorders of the low back. Philadelphia: Lea & Febiger; 1973. p. 181-2. 29. Yochum T, Rowe L. Essentials of skeletal radiology. Vol 1. Baltimore: Williams & Wilkins; 1987. p. 182. 30. Manni E, Giovanni P, Rolando M, Pettorossi VE. Trigeminal influences on extensor muscles on the neck. Exp Neurol 1975;47:330-42. 31. Green JD, DeGroot J, Sutin J. Trigemino-bulbar reflex pathways. Am J Physiol 1957;189:384-8. 32. Abrahams VC. The physiology of neck muscles: their role in head movement and maintenance of posture. Can J Physiol 1977;55:332-8. 33. Kerr FW, Olafson RA. Trigeminal and cervical volleys. Arch Neurol 1961;5:69-76. 34. Abrahams VC, Anstee G, Richmond FJR. Further studies on the organization of the upper cervical cord. Proc Can Fed Biol Soc 1976;19:146.
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35. Alstermark B, Pinter MJ, Sasaki S, Tantisria B. Trigeminal excitation of dorsal neck motoneurons in the cat. Exp Brain Res 1992;92:183-93. 36. DiLazzaro V, Quartarone A, Higuchi K, Rothwell JC. Shortterm latency trigemino-cervical reflexes in man. Exp Brain Res 1995;102:474-82. 37. Bogduk N. The anatomical basis for cervicogenic headache. J Manipulative Physiol Ther 1992;15:67-70. 38. Hart J. Effect of patient positioning on an upper cervical x-ray listing: a case study. J Chiropract Res 1988:(Autumn) 19-21. 39. Palmer T, Denton K, Palmer J. A clinical investigation into upper-cervical biomechanical stability: part 1. Upper Cervical Monogr 1990;4(10):2-7. 40. Coggeshall RE, Hong KA, Langford LA, Schaible HG, Schmidt RF. Discharge characteristics of the fine medial articular afferents at rest and during passive movements of inflamed knee joints. Brain Res 1983;272(1):185-8. 41. Knutson G. Moderation of postural distortion following upper cervical facet joint block injection: a case study. Chiropract Res J 1998;5:28-34.
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42. Macaluso GM, De Laat AD, Pavesi G. The influence of the asymmetric tonic neck reflex on the H-reflex in human temporal muscle. Minerva Stomatol 1996;45:387-92. 43. Ormeno G, Miralles R, Santander H, Casassus R, Ferrer P, Palazzi C, et al. Body position effects on sternocleidomastoid and masseter EMG pattern activity in patients undergoing occlusal splint therapy. J Craniomandib Pract 1997;15:300-9. 44. Hellebrandt FA, Schade M, Carns M. Methods of evoking the tonic neck reflexes in normal humans subjects. Am J Phys Med 1962;41:90-135. 45. Connolly BH, Michael BT. Early detection of scoliosis: a neurologic approach using the asymmetrical tonic neck reflex. Phys Ther 1984;64:304-7. 46. Marinelli PV. The asymmetric tonic neck reflex: its presence and significance in the newborn. Clin Pediatr 1983;22:544-6. 47. Chinappi AS, Getzoff H. Chiropractic/dental cotreatment of lumbosacral pain with temporomandibular joint involvement. J Manipulative Physiol Ther 1996;19:607-12. 48. Chinappi AS. A new management model for treating structuralbased disorders: dental orthopedic and chiropractic co-treatment. J Manipulative Physiol Ther 1994;17:614-9.