Posture and Headaches
Posture and Headaches
Mark W Morningstar, DC, Greg Gilmour, DC
Headache pain has troubled mankind from the dawn of civilization.1 Among these, cervicogenic headaches (CH) and tension-type headaches (TTH) are two types that have been shown to have etiologies related to structures in the cervical spine. Mechanical problems are exacerbated and alleviated by mechanical means. Therefore, it seems logical to assume that the best way to treat these headaches is through mechanical means when mechanical etiologies are diagnosed. In light of this rationale, it is appropriate to discuss the relationship between posture and these two types of headaches, along with both traditional and manipulative treatments. Perhaps posture correction should be considered as a primary intervention, due to its comprehensiveness and emphasis on patient home care.
Neurological and Mechanical Mechanisms
It is difficult to pinpoint a singular etiology for TTH, although several mechanisms have been reported2-5. Jensen and Olesen2 reported that muscle contraction precipitated by teeth clenching resulted in increased muscle tenderness and subsequent headache, supporting the use of oromandibular treatment for TTH. This model demonstrates the relationship between muscle contraction and TTH. Another model, proposed by Olesen3, has a more central emphasis. This model discusses myofascial nociception and how it may contribute to pericranial tenderness and ultimately sensitization of the central nervous system, a concept discussed in detail by Seaman and Winterstein6.
Cervicogenic Headache has received particular attention from the physical medicine field due to its relationship to the structure and function of the upper cervical spine. In fact, there are several articles that address the possible etiologies linked to the upper cervical spinal structures.7-10 Therefore, a detailed description of the anatomy and pathophysiology of this region will not be discussed presently. However, less attention has been given to the importance of temporomandibular dysfunction (TMD) and its relationship to CH. Perhaps this is due to the fact that the cervical spine and the mandible are intimately connected through both the neurology and the musculature.10-11 Several neck flexor muscles also act to open the mandible, such as the omohyoid, suprahyoid, mylohyoid, sternohyoid, thyrohyoid, and infrahyoid muscles. The symptoms associated with CH are very similar in nature to the symptoms found in TMD. Cervicogenic headaches and temporomandibular joint pain are both carried by the trigeminal nerve. Therefore, it is possible that nociception from the TMJ may be interpreted as headache pain, due to the convergence of pathways at the spinal trigeminal nucleus caudalis. Differential diagnosis is important so that inappropriate care can be avoided. If TMD is determined to be the cause of clinical symptoms, then it is also prudent to evaluate the structure and function of the cervical spine, so that mechanical derangements may be ruled out.
Abnormal curves in the cervical spine are more common in patients with cervicocranial symptoms.12,13 Takeshima et al14 concluded that alterations in the static alignment of the cervical curve cause alterations in the motion quality during cervical flexion and extension. Brieg15 and Harrison et al16,17 have previously illustrated how loss of the cervical lordosis can place increased strain on the spinal cord and brain stem through Poisson’s Effect and the Law of LaPlace. The trigeminal nucleus of cranial nerve V is located within the brainstem. Additionally, there is significant evidence that the spinal trigeminal nucleus caudalis has a caudad extension that may function as a trigeminal nucleus cervicalis1 Therefore, it is possible that prolonged tension on the brainstem and cervical spinal cord may affect both the quantitative and qualitative properties of the trigeminal nerve’s associated primary and secondary motor neurons.18 These findings may contribute to the sensitization and ultimate activation of the trigeminovascular system, a process to which Silberstein1 attributes headache pain. In addition, forward translation of the skull and cervical spine places abnormal stresses on the lower cervical vertebrae (C5-C7), leading to early degenerative change at these levels.19 These levels innervate the paraspinal musculature of the lower cervical and upper thoracic regions, such as portions of the trapezius, levator scapulae, splenius, longissimus, and multifidus muscles. As the lower cervical discs and joints degenerate, they may cause regional sensitization due to chronic inflammatory processes at these levels, leading to a concept of Dysafferentation introduced by Seaman and Winterstein.6 This concept has also been termed the “wind-up” phenomenon by other authors.1 This resultant aberrant barrage of afferent input results in increased firing of efferent fibers through sensitization of the local interneurons. The end result is increased tonicity of the lower cervical and upper thoracic musculature, which may give rise to TTH. This increased tonicity may also be due to forward head posture, which forces the posterior cervical extensor muscles to contract isometrically for longer periods of time to balance the head appropriately. Takeshima et al14 also reported that the static alignment of the cervicothoracic junction was closely related to an abnormal cervical lordosis. This may also be a contributing factor to increased tonicity of the cervicothoracic musculature.
Bogduk7,8 claims that the alar ligaments can also be a source of pain in cervicogenic headache. However, there is also evidence to suggest that alar ligament damage may also be involved, at least partially, in tension-type headache. When an alar ligament is damaged, the upper cervical spine is strongly stabilized by the intrinsic cervical musculature.20 Since ligaments do not ever heal fully, the intrinsic muscles must accommodate for this lost stabilization. The result is strong isometric muscle contractions, which may give rise to tension-type headaches. In fact, Sakai et al21 found shoulder and neck muscles to be much harder in TTH. Schulman22reports that muscle hardness positively correlates to muscle tenderness and supports the clinical observation that tender muscles are harder than normal muscles. Muscle hardness was significantly higher and permanently altered in chronic TTH.22,23
Medications commonly prescribed for cervicogenic headache include several types. Tricyclic anti-depressants, NSAIDS, muscle relaxants, and antiepileptic drugs have long been used for the prevention and treatment of neuropathic, musculoskeletal, head, and face pain syndromes.24 Biondi24 explains that medication, when used as the sole treatment for headache, does not produce substantial pain relief in many cases. However, use of these medications may allow a patient to be more actively involved in a physical rehabilitation program.24
Pikus and Phillips25, using a surgical decompression technique for the treatment of cervicogenic headache, reported a 90% success rate. During these procedures, they noted incidents of C2 venous compression in 86% of cases, atlantal-axial ligament hypertrophy in 66% of cases, and rostral distortion of the nerve root in 49% of cases.25 Their findings support a previous review by Harrison et al17, where these types of findings were predicted to occur in subjects with forward head posture and loss of cervical lordosis.
Manual or manipulative therapy has shown encouraging results in the symptomatic treatment of TTH and CH.24,26-29 However, this form of treatment has typically focused upon treating joint dysfunction or restriction. The goal of manipulation is usually to restore range of motion in the upper cervical spinal joints and relax the supportive regional musculature.29 As outlined by Janse10 and more recently by Bogduk7,8, the upper cervical zygapophyseal joints are neurologically connected to the occiput, mandible, lower cervical spine, and cranial nerve V through the spinal trigeminal nucleus. This lays the neurological foundation for the development of referred pain to the jaw, face, occipital region, and forehead. These pain patterns are typical in patients with TTH and CH. However, the range of motion restored by spinal manipulative therapy (SMT) has been shown to have only short-lasting effects equivalent to about one week.38 SMT tends to emphasize only the functional portion of the structure-function relationship. As Grimshaw explains29, it is erroneous to refer to a spinal joint as being “out of place,” when discussing manipulative treatment and outcomes. If a spinal joint is, in fact, “out of place,” then a surgical consultation is appropriate for that circumstance. Therefore, SMT is only effective at mobilizing fixated joints, and does not address the global structure of the spine. As some authors note29,30, the structure of the cervical spine, specifically, the loss of cervical lordosis and forward head posture, can be a factor in the development of TTH and CH. Siderstein1 outlines a nonpharmacologic treatment of TTH as improvement of posture through stretching, exercise, and traction. Other alternative treatments have shown at least short term relief, such as massage, oromandibular treatments including occlusal splints, masticatory exercises, and occlusal adjustment, and physiotherapy consisting of therapeutics modalities like trigger point injections and occipital nerve blocks.1 In light of this evidence, the reader can conclude that spinal manipulation alone is not as effective at treating these types of headaches as SMT combined with certain forms of active spinal rehabilitation. In fact, the superiority of SMT combined with physical rehabilitation has already been previously reported.29,31,32
Normal Cervical Lordosis and Forward Head Posture
Harrison et al33 have identified and published a model of normal and ideal values for the cervical lordosis and forward head posture. This model identifies a normal cervical lordosis as a 34° angle when measured from the posterior vertebral body margins of the C2 and C7 vertebrae, as well as about 1” of forward head posture or less.33 Since the derivation of these normative values, chiropractic physicians now have the ability to assess the effectiveness of their treatment regimens, as well as being able to work with objective outcome measures. Pettibon Spinal Biomechanics techniques are showing promise when addressing the loss of cervical lordosis and forward head posture.34-38 These techniques combine SMT with specific forms of neuromuscular re-education through the use of anterior headweighting and bodyweighting. These procedures are also incorporated into patient home care rehabilitation, a concept supported by many manual medicine practitioners.
While tension-type headache and cervicogenic headache are still controversial in both diagnostic criteria and mechanisms, there does appear to be a significant amount of evidence supporting the use of manual treatment for TTH and CH in the presence of cervical mechanical dysfunction and structural alteration.29,39 Cervical spine dysfunction may be related to an abnormal static alignment of the cervical spine14, according to the normal published values.33 Therefore, it may be necessary to evaluate the structure of the cervical spine radiographically due to evidence showing that visualization of posture is not reliable.40 Spinal manipulative therapy, when used to treat these types of headaches, should be used in conjunction with active physical rehabilitation. This results in quicker reduction of symptoms, as well as a decreased number of reported relapses.29 If the loss of cervical lordosis or forward head posture is present with tension-type or cervicogenic headache symptoms, then one goal of the practitioner should be to restore the normal cervical lordosis and forward head posture. More practitioners in the manual healing arts should place more emphasis on the static structure of the spinal column when treating various forms of spinal, head and face pain syndromes.
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32. Morningstar M. Cervical curve restoration and forward head posture reduction for the treatment of mechanical thoracic pain using the pettibon corrective and rehabilitative procedures. J Chiropr Med 2002; 1: 113-115
33. Harrison DD, Janik TJ, Troyanovich SJ, Harrison DE, Colloca CJ. Evaluations of the assumptions used to derive an ideal normal cervical spine model. J Manipulative Physiol Ther 1997;20:246-254
34. Saunders ES, Woggon D, Cohen C, Robinson DH. Improvement of cervical lordosis and reduction of forward head posture with anterior headweighting and proprioceptive balancing protocols. J Vertebral Sublux Res 2003; 4:1-5
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36. Morningstar MW, Strauchman MN, Weeks DA. Spinal manipulation and anterior headweighting for the correction of forward head posture and cervical hypolordosis: a pilot study. J Chiropr Med 2003;2:51-55
37. Morningstar MW. Cervical hyperlordosis correction: a novel treatment method for mid thoracic pain. J Chiropr Med 2003 (Accepted for Publication)
38. Morningstar MW. Strength Gains Through Lumbar Lordosis Restoration. J Chiropr Med 2003 (Accepted for Publication)
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Posture Magazine, December 2003 issue