EMG study on the neck muscle function in the group of forward head posture

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This research was composed of two studies of the neck muscle function and the mandibular position in the positions of forward and natural head postures.1) EMG study on the neck muscle: Objectives: Purpose of this study is to investigate the neck muscle function with EMG in the groups of forward and natural head postures. Materials and methods: Five male subjects with forward head posture and 7 male subjects with natural head posture from university dental students were used in this study. The EMG of sternocleidomastoid, sternohyoid, trapezius, digastric, masseter and temporal muscles were measured in both the forward head and natural head postures. Results: The sternocleidomastoid muscle activities in position of both forward and natural head posture were significantly greater in the group of forward head posture than in the group of natural head posture. The trapezius muscle activity in position of forced forward head posture was significantly smaller in the group of forward head post … More ure than in the group of natural head posture. Sternohyoid, digastric, masseter and temporal muscles activities were no significant difference between the both groups. Conclusion: Overloading the sternocleidomastoid muscle was suggested in the group of forward head posture. The symptoms of sternocleidomastoid muscle have been well reported in the patients of temporomandibular dysfunction with the muscle pain of the neck region. It has been suggested that the forward head posture is one of the factor of the TMD with the muscle pain of the neck region.2) Mandibular position study: Objectives: Purpose of this study is to investigate the mandibular position in the positions of forward and rotating head postures. Materials and methods: Fifteen adult male subjects without TMD, malocclusion and missing teeth were used in this study. The mandibular positions were measured in the positions of forward and natural head posture and 60 degrees rotating head on the sitting position using the mandibular movement analyzing system. Results: The mandible moved to right back upward position with slightly rotating in the position of forward head posture and moved to backward position of the rotating side while lower incisor point moved to opposite side in the head rotation. Conclusion: In the position of forward or rotate head, the soft tissue around neck and face region was stretched which moved the mandible to backward rotation and retro-position. Less