STRUCTURE AND FUNCTION OF JAW MUSCLES IN RAT (RATTUS NORVEGICUS L) .3. MECHANICS OF MUSCLES
STRUCTURE AND FUNCTION OF JAW MUSCLES IN RAT (RATTUS NORVEGICUS L) .3. MECHANICS OF MUSCLES
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DOI：
10.1111/j.1096-3642.1971.tb00754.x
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发表时间：
1971-01-01
影响因子：
2.8
通讯作者：
HIIEMAE, K
中科院分区：
文献类型：
--
作者：
HIIEMAE, K
利用“中枢纤维”的概念，构建了大鼠咀嚼肌肉及其在产生下颌运动中的作用的力学模型。这些肌肉沿着它们的运动路线所能施加的相对力已经计算出来了。求出了力在水平、垂直和横向平面上的矢量。利用这些数据，证明了在静止位置上关于颚的矢量力分布。计算了关节周围肌肉在休息位置的力矩，以及在吞咽和咀嚼循环中，每一划开始时下颌骨所取的相应位置的力矩。每一块肌肉的力矩的变化都是由下颌位置的变化所引起的，并描述了每一块肌肉的有效作用。所有的肌肉都倾向于抬高下颌骨，除了颞前和颞后，都倾向于延长下颌骨。后颞是下颌的主要牵开器，但也可由前颞辅助牵开。除了在休息位置和自由运动时稳定颌骨的垂直和水平位置外，在咀嚼用力时，深咬肌和前颞肌提升下颌。前深咬肌和它的眶下部分在食入的尖锐中风中有相同的功能，可能是由深咬肌辅助的。除了延长下颌骨外，浅咬肌还可以在咀嚼的有力动作和进食的尖锐动作中调节下颌的位置。内翼和外翼被认为具有主要的稳定功能。通过对磨牙在咀嚼动力行程时受力的计算表明，下颌在该位置处于平衡状态，关节上没有载荷。然而，在尖锐的摄入过程中，关节作为第三级杠杆起作用，并且负荷很大。
A mechanical model of the muscles of mastication and their effect in producing movement of the lower jaw in the rat has been constructed using the concept of the ‘central fibre’. The relative forces these muscles can exert along their lines of action have been calculated. The vectors of the force in the horizontal, vertical and transverse planes have been found. Using these data, the distribution of vector forces about the jaw in the rest position has been demonstrated. The moments of the muscles about the joint in the rest position and in positions corresponding to those taken by the mandible at the beginning of each stroke during the cycles of ingestion and mastication have been calculated. The changes in the moment of each muscle produced by changes in the position of the jaw have been assessed and the effective action of each described. All the muscles tend to elevate the mandible and, with the exception of the anterior and poterior temporal, to protract it. The posterior temporal is the main retractor of the jaw but may be assisted by the anterior temporal. In addition to stabilizing the vertical and horizontal positions of the jaw in the rest position and during free movements, the deep masseter and anterior temporal elevate the lower jaw during the power stroke of mastication. The anterior deep masseter and its infra-orbital part have the same function during the incisive stroke of ingestion and are probably assisted by the deep masseter. In addition to protracting the mandible, the superficial masseter may act as a regulator of jaw position during the power stroke of mastication and in the incisive stroke of ingestion. The internal and external pterygoids are considered to have a predominantly stabilizing function. Calculation of the forces acting about the molars during the power stroke of mastication indicates that the jaw is in equilibrium in this position and there is no load on the joint. However during the incisive stroke of ingestion the joint is functioning as a lever of the third order and is heavily loaded.