Management of Craniomandibular Disorders. Part 1: A Craniocervical Dysfunction Index A craniocervical dysfunction index has been developed (based on the Helkimo Dysfunction Index) to comprehensively assess cranio- cervical dysfunction and to objectively monitor the management of patients who present with these clinical problems. The close func- tional interrelationship of temporomandibular joints, jaw muscles, and cervical joints and muscles is reviewed, and a mechanism is proposed to explain dysfunctional relationships between these structures. This is the first of three papers stemming from a clinical study that investigated craniomandibular disorders and assessed the effect of routine dental management on craniomandibular and craniocervical dysfunction. J OROFACIAL PAIN 1993:7:83-88 Christine Wallace. BDS, MDSc unctiotial relationships exist between jaw and cervical muscles Former Lecturer involved in head, neck, and jaw movements. Posterior cervical Department of Prosthetic Dentistry Fmuscles of special importance include the trapezius and dorsal Iven J. Klineberg, BSc MDS. PhD. neck muscles, which support the head anteroposteriorly, and the FRACDS. FDSRC^ (Eng). FICD sternocleidomastoid muscles, which control head rotation. Anterior Professor neck muscles, both suprahyoid and infrahyoid groups, have an artment of Prosthetio Dentistry important role: the suprahyoid muscles (mylohyoid, hyoglossus, geniohyoid, and digastric) are closely associated with tongue func- University of Sydney Sydney. Australia tion, while the infrahyoid group essentially supports the hyoid bone. As a result of these functions, close and complex integration Correspondence to: of these muscle groups is essential for fluent neck, jaw, and tongue Prof Iven Klineberg function. Professorial Unit, Level 3 Sherrington' showed that a clearly defined neurophysiologic Westmead Hospital Dental relationship exists between dorsal neck and jaw muscle function. Clinical School Westmead NSW 2145 More recent neurophysiologic studies" have described an Australia expanded role for the trigeminal system in the control of head and shoulder movement, additional to its primary role of subserving nociception from orofacial tissues.'"^ Abrahams and Richmond^ proposed that the cervical spinal cord and its associations with the trigeminal system represent a special- ized receptor system. Clinically, damage to neck structures (often as a result of whiplash trauma) causes a variety of symptoms, including disturbances of gait and vision, and dizziness. Cervical nerves Cl to C4 are primarily associated with head posture,' and afférents from Cl to C4 relay in nucleus caudalis, the most caudal region of the trigeminal sensory nucleus and the primary region for transmission of trigeminal nociceptive afférents. Non-nociceptive afférents may project to deeper portions of nucleus caudalis^ as well as to more rostral areas of nucleus oralis and interpolaris.^'" Journal of Orofacial Pain 83 Wallace This neurologic infrastructure provides a basis occlusion and/or abnormal temporomandibular for the intimate association between craniocervical joint (TMJ) mechanics and although this form of and jaw posture. This association has also been treatment often helped the patient initially, acknowledged from clinical studies, and Brodie" improvement was usually not maintained long- emphasized that integrated head and cervical mus- term. Abnormal head, neck, shoulder, and cle function was required for maintaining head mandibular posture may have been responsible for posture. Clinical observation of patients presenting the relapse following treatment directed solely at with temporomandibular dysfunction (TMD) has the TMJ. This suggested the need for upper-body indicated that cervical pain is a commonly occur- biomechanical evaluation for all patients with ring feature,''"'' and occlusal relationships have craniomandibular pain and dysfunction. been proposed as a possible etiologic factor.'''^ Craniomandibular disorders (CMD) may result The varied symptoms that may be associated in symptoms of referred pain as well as local mus- with cervical dysfunction (noted by Abrahams and culoskeletal pain. Local symptoms include Richmond') in association with TMD were investi- decreased range of mobility, muscular stiffness and gated by Norris and Fakin."' These authors found pain, and degenerative or osteoarthritic changes in a predominance of female patients with symptoms spinal joints. These symptoms may arise as a result including cervical pain, pain in and around the ear of sustained muscular contraction, poor posture, and down the neck, aching and tightness in the and subsequent mechanical compression of neu- submandibular area, and sometimes a burning rovascular elements, cervical vertebral joints, and sensation in the neck and pain in the ipsilateral cervical nerve roots. Other local symptoms attrib- shoulder. uted to craniocervical problems are complaints of Reider" examined a population of "apparently soreness and/or tightness in the throat and when healthy" subjects and found a high incidence of swallowing, which may be due to a change in cer- occlusal habits, headache, and neck ache. The vical curvature, and is characterized by a forward prevalence of headache and neck ache occurring head posture with increased tension of anterior one or more times each month in this population neck structures. was 43% with headache, 17% with neck ache, Considering the multiplicity of signs and symp- and 11% with both headache and neck ache. toms that may arise from altered head posture, it Hellsing'' and Hellsing et al'"' examined head is evident that there is a direct relationship and body posture in children and found that lum- between craniovertebral abnormalities and CMD. bar and thoracic spinal curvature increased with Ideal head posture places its center of gravity age and that cervical Iordosis was related directly slightly anterior to the cervical spine. For this rea- to head posture and mode of breathing (ie, nose or son, when the subject is sitting or standing, the mouth). Mode of breathing influenced resting lip head falls anteriorly if the cervical muscles are pressure and anterior tooth arrangement. There totally relaxed. To maintain this orthostatic or were also marked changes in posterior cervical postural position, strong posterior cervical muscle muscle electromyographs (FMG), where flexion activity is needed to balance these forces. The (head forward) increased EMG and extension anterior cervical muscles are small, thin muscles (head backward) decreased EMG in these muscles, that stretch from the clavicle, sternum, and rib but increased sternocleidomastoid EMG. Both cage to the hyoid bone (infrahyoid muscles) and extension and flexion increased infrahyoid muscle from the hyoid bone to the mandible (suprahyoid activity, presumably to maintain hyoid bone posi- muscles). Three-dimensional stability of the hyoid tion in association with a patent airway. bone is maintained by complex reflex-muscle influences in relation to airway maintenance. Two other important muscles that influence the posi- Posture tion and stability of the head and neck are the ster- nocleidomastoid muscle anteriorly and the levator Postural or "orthostatic" stability of the cranium scapulae muscles posteriorly. Mandibular move- to the cervical spine is an important diagnostic ment is controlled by jaw muscles and relates to consideration of craniomandibular pain and dys- the cranium through the articulation of the teeth function. However, this is not always acknowl- and TMJs. This complex relationship is important edged in diagnosis and management of such because the mandible is attached in this way to patients, even when there is obvious cervical pain both the cranium and the shoulder girdle, and and dysfunction. Management strategies for cran- positional changes of either will result in postural iomandibular pain have been directed toward mal- changes of the mandible. 84 Volume 7. Number 1, 1993 Wallace Rocabado et aF^ reported a correlation between Table 1 Craniocervical Dysfunction Index Class II malocclusion and forward head posture of 70%, providing strong evidence for a close interre- Criteria Score lationship of head posture and malocclusion. In A Impaired range of movement/mobility index tbeir stuciy a typical adult patient with TMD pre- Normal range of movement 0 sents with a deep overbite or Class II malocclusion Slightly impaired movement 1 and forward head posrure. Such patients may Severely impaired movement 5 develop facial pain, abnormal TMJ mechanics, B Impaired cervical joint function and compression of upper cervical facet joints, Smooth movement without cervical joint sounds or pain on movement 0 which result in suboccipital headache or headache Cervical joint sounds—clicking, referred to the craniofacial region from cervical popping or grating noises with muscles. Abnormal head posture may also predis- head movement 1 pose to fatigue of cervical muscles and compres- Locking—head or neck becoming sion of facet joints of the cervical spine, and this momentarily fixed 5 may cause neck pain and referred pain into the G Muscle pain arm and the intercapsular area. The forward head No tenderness to palpation in the cervical muscles 0 posture favors abduction and protraction of the Tenderness to palpation in 1 to 3 scapula, which over long periods may create palpation sites 1 shoulder girdle symptoms and encourage further Tenderness to palpation in 4 or more changes in spinal curvature. Thus, TMD may be palpation