Hylander W L, Johnson K R, Crompton A W
Am J Phys Anthropol. 1987 Mar;72(3):287-314. doi: 10.1002/ajpa.1330720304.
Rosette strain gage, electromyography (EMG), and cineradiographic techniques were used to analyze loading patterns and jaw movements during mastication in Macaca fascicularis. The cineradiographic data indicate that macaques generally swallow frequently throughout a chewing sequence, and these swallows are intercalated into a chewing cycle towards the end of a power stroke. The bone strain and jaw movement data indicate that during vigorous mastication the transition between fast close and the power stroke is correlated with a sharp increase in masticatory force, and they also show that in most instances the jaws of macaques are maximally loaded prior to maximum intercuspation, i.e. during phase I (buccal phase) occlusal movements. Moreover, these data indicate that loads during phase II (lingual phase) occlusal movements are ordinarily relatively small. The bone strain data also suggest that the duration of unloading of the jaw during the power stroke of mastication is largely a function of the relaxation time of the jaw adductors. This interpretation is based on the finding that the duration from 100% peak strain to 50% peak strain during unloading closely approximates the half-relaxation time of whole adductor jaw muscles of macaques. The EMG data of the masseter and medial pterygoid muscles have important implications for understanding both the biomechanics of the power stroke and the external forces responsible for the "wishboning" effect that takes place along the mandibular symphysis and corpus during the power stroke of mastication. Although both medial pterygoid muscles reach maximum EMG activity during the power stroke, the activity of the working-side medial pterygoid peaks after the balancing-side medial pterygoid. Associated with the simultaneous increase of force of the working-side medial pterygoid and the decrease of force of the balancing-side medial pterygoid is the persistently high level of EMG activity of the balancing-side deep masseter (posterior portion). This pattern is of considerable significance because the direction of force of both the working-side medial pterygoid and the balancing-side deep masseter are well aligned to aid in driving the working-side lower molars across the upper molars in the medial direction during unilateral mastication.(ABSTRACT TRUNCATED AT 400 WORDS)
采用玫瑰花结应变片、肌电图（EMG）和X线电影摄影技术，分析猕猴咀嚼过程中的负荷模式和颌骨运动。X线电影摄影数据表明，猕猴在整个咀嚼过程中通常频繁吞咽，且这些吞咽动作在动力冲程接近尾声时插入咀嚼周期。骨应变和颌骨运动数据表明，在剧烈咀嚼时，快速闭合与动力冲程之间的过渡与咀嚼力的急剧增加相关，并且还表明，在大多数情况下，猕猴的颌骨在最大牙尖交错之前，即在I期（颊侧期）咬合运动期间承受最大负荷。此外，这些数据表明，II期（舌侧期）咬合运动期间的负荷通常相对较小。骨应变数据还表明，咀嚼动力冲程期间颌骨卸载的持续时间在很大程度上取决于颌内收肌的松弛时间。这一解释基于以下发现：卸载过程中从100%峰值应变到50%峰值应变的持续时间与猕猴整个内收颌肌的半松弛时间非常接近。咬肌和翼内肌的EMG数据对于理解动力冲程的生物力学以及咀嚼动力冲程期间沿下颌联合和下颌体发生的“叉骨”效应所涉及的外力具有重要意义。尽管两侧翼内肌在动力冲程期间均达到最大EMG活动，但工作侧翼内肌的活动在平衡侧翼内肌之后达到峰值。与工作侧翼内肌力量的同时增加和平衡侧翼内肌力量的减少相关的是平衡侧深层咬肌（后部）持续高水平的EMG活动。这种模式具有重要意义，因为工作侧翼内肌和平衡侧深层咬肌的力的方向排列良好，有助于在单侧咀嚼时将工作侧下磨牙向内驱动越过上磨牙。（摘要截断于400字）
