Lafrenière C M, Lamontagne M, el-Sawy R
School of Human Kinetics, University of Ottawa, Ontario, Canada.
Cranio. 1997 Jan;15(1):38-52. doi: 10.1080/08869634.1997.11745991.
Intramuscular EMG of the lateral pterygoid muscles (LPM), surface EMG of the temporalis and masseter muscles and force measurements of the temporomandibular joint (TMJ) were synchronously used to investigate the biomechanical role of the two heads of the LPM in relation to internal derangement (ID) of the TMJ. EMG and kinetic analysis of five static conditions (resting, protraction, opening, molar and incisor clenching) and three maximum isometric masticatory forces (opening, molar and incisor clenching) were done to compare forces and muscular activity between TMJ ID and control subjects. The analysis of variance results of the integrated linear envelope (LE) EMG showed no significant differences between the two groups for the masseter and temporalis muscles. Therefore, there is no apparent reason to believe that these muscles are hyperactive in TMJ ID. The integrated LE EMG of the SLP was significantly lower in the TMJ group during molar clenching (104 microV + 60.0 over 159 microV + 68.8 for a p = .020). The superior head of the lateral pterygoid muscle (SLP) seemed to have lost its diskal stabilizing function. The integrated LE EMG signals of the ILP were significantly higher in the TMJ ID group during rest, resisted protraction and incisor clenching (p = .029, p = .046, p = .031 respectively). The ILP muscle has probably adapted to control the inner joint instability while continuing its own actions. The ILP muscle seemed to have lost its functional specificity. The results of the isometric forces showed that TMJ ID subjects exhibited significantly lower molar bite forces (297.1N over 419N, p = .042) confirming that they have less muscle strength and tissue tolerance than subjects with healthy masticatory muscle systems. A neuromuscular adaptation could be occurring in the TMJ ID masticatory system affecting muscular actions and forces.
同步使用翼外肌（LPM）的肌内肌电图、颞肌和咬肌的表面肌电图以及颞下颌关节（TMJ）的力测量，以研究翼外肌两个头在颞下颌关节内紊乱（ID）方面的生物力学作用。对五种静态条件（休息、前伸、开口、磨牙和切牙紧咬）和三种最大等长咀嚼力（开口、磨牙和切牙紧咬）进行肌电图和动力学分析，以比较颞下颌关节ID患者和对照组之间的力和肌肉活动。积分线性包络（LE）肌电图的方差分析结果显示，咬肌和颞肌在两组之间无显著差异。因此，没有明显理由认为这些肌肉在颞下颌关节ID中过度活跃。在磨牙紧咬期间，颞下颌关节组中翼外肌上头（SLP）的积分LE肌电图显著更低（104微伏 + 60.0，而对照组为159微伏 + 68.8，p = 0.020）。翼外肌上头似乎失去了其盘状稳定功能。在休息、抵抗前伸和切牙紧咬期间，颞下颌关节ID组中翼外肌下头（ILP）的积分LE肌电图信号显著更高（分别为p = 0.029、p = 0.046、p = 0.031）。翼外肌下头可能已适应控制关节内部不稳定，同时继续其自身动作。翼外肌下头似乎失去了其功能特异性。等长力的结果表明，颞下颌关节ID患者表现出显著更低的磨牙咬合力（297.1牛，而对照组为4,19牛，p = 0.042）证实他们比具有健康咀嚼肌肉系统的受试者肌肉力量和组织耐受性更低。颞下颌关节ID咀嚼系统中可能正在发生神经肌肉适应性变化，影响肌肉动作和力量。
