Influence of tonic postural reflex on the masticatory and neck, shoulder and back muscles

为探讨张力性前庭反射和躯干反重力肌肉传入冲动对下颌运动时颈、肩、背部兴奋状态的影响，对13名健康成人进行了不同体位的肌电检查，结果如下：1.在自主等长持续牵引训练中，同时激活颈肌和胸锁乳突肌。结果：1.在最大运动周期的60%时间后，前者背部的肌电幅值变大，频率变低，提示疲劳。在前后颌运动过程中，SCM上部的肌电变化与侧颌运动时相似。体位效应在SCM的下部也很明显，即站立和后倾姿势(30度角)时肌电幅值较高，俯卧位、仰卧位和6度斜位时的肌电幅度较低。这些结果可能表明，犹太人运动对颈部、肩部和背部肌肉的影响是由前庭系统和反重力肌肉的传入输入调节的。

In order to evaluate the effects of tonic vestibular reflex and the afferent impulses from the antigravity muscles of the extremities and of the trunk on an excitatory state of the neck, shoulder and back portions during the jaw exercise, 13 healthy adults were electromyographically examined in various body postures.The results abstained were as follows ;1. During voluntary isometric sustained jaw pull exercise, the nuchal and sternocleidomastoid (SCM) muscles were also activated. After the time of 60% of the maximum exercise period, EMG form the back portion of the former became larger in an amplilude and lower in the frequency, suggesting the fatigue of it.2. Similar EMG changes in the superior portion of SCM were clearly observed during the antero-posterior jaw exercise rather than during lateral jaw exercise.3. Postural effects were also evident in the inferior portion of SCM, i. e. higher EMG amplitude obtained at standing and backward inclined postures (30 degrees in angle), while lower EMG at prone, supine and further 6 degrees inclined postures.4. These results might suggest that the effects of the jew exercise on the muscles of the neck, shoulder and back portions were modulated by an afferent input from the vestibular system and from antigravity muscles.