STRAIN IN THE FACIAL BONES OF PRIMATES

这里提出的研究将有助于功能的理解 灵长类动物面部区域的形态。灵长类动物的脸是 本研究将分析 咀嚼力的性质和这些力是如何消散的 在灵长类动物的脸上。应遵循的一般方法是 表征沿着面部的体内表面骨应变的模式 灵长类动物食蟹猴的骨头然后，使用各种 各种解剖和生理数据（例如，肌肉形态，颌- 运动和/或颌肌肌电图数据），内部运动模式 表面的各种（和假定的）结构构件内的应力是 从这些数据中推断出来。主要目标是确定是否 以及给定的骨头或骨头的一部分在多大程度上以及在哪个方向上 在不同的行为过程中紧张，然后使用这些骨应变 数据来制定和测试关于各种负载模式的假设 面部骨骼也就是说，要确定有多少和在什么方向的面部 骨骼在正常情况下弯曲和/或扭曲和/或剪切等 功能 将沿猕猴的面骨沿着测量体内应变 使用应变计测量束状肌。玫瑰应变片（三个应变片 彼此具有已知取向的元件）直接结合到 用氰基丙烯酸酯粘合剂粘合面部骨骼。猕猴咬了一口 传感器（或咀嚼各种食物），骨应变监测上， 示波器上，并记录在调频磁带录音机。在某些情况下 不同颌部肌肉同时肌电图（EMG）活动 也可以用示波器监测并记录在调频磁带上 录音机。主应变的大小和方向为： 确定，以及EMG的均方根分析。后 表面应变的特点是沿着不同区域的 面（例如，眶后杆，前根， 后犬齿牙槽突和下颌骨的基底部分），模式 内应力的大小可以从表面应变的模式中推断出来。这 是为了了解猕猴的面部骨骼是如何 咀嚼应力 这项工作将有助于解释为什么灵长类动物（包括人类）的面部骨骼 他们的样子此外，通过表征机械 面部骨骼的环境，这些数据可以提供关于如何以及 为什么面骨会对各种不同的机械应力做出反应， 从而有助于更好地了解与下列方面有关的进程： 口腔骨质流失，骨骼机械强度的维持， 生长修饰植物形态多样性的解释 然而，灵长类动物的脸必然涉及的不仅仅是一个 考虑机械应力和生物力学缩放。 然而，这种形态多样性往往具有重要的意义。 结构性后果，正是这些后果， 研究是有指导的。

The research proposed here will contribute to a functional understanding of the morphology of the primate facial region. The primate face is dominated by the masticatory apparatus and this research will analyze both the nature of masticatory forces and how these forces are dissipated throughout the primate face. The general approach to be followed is to characterize patterns of in vivo surface bone strain along the facial bones of an anthropoid primate, Macaca fascicularis. Then, using various sorts of anatomical and physiological data (e.g., muscle morphology, jaw- movement and/or jaw-muscle electromyographic data), patterns of internal stress within various (and supposed) structural members of the face are inferred from these strain data. The primary goal is to determine whether and how much and in which direction a given bone or portion of a bone is strained during different behaviors, and then to use these bone strain data to formulate and test hypotheses about loading patterns in various facial bones. That is, to determine how much and in what direction facial bones are bent and/or twisted and/or sheared, etc. during normal function. In vivo strain will be measured along the facial bones of Macaca fascicularis using strain gages. Rosette strain gages (three strain-gage elements with a known orientation to one another) are bonded directly to facial bones with a cyanacrylate adhesive. The macaque then bites a transducer (or chews various foods), and bone strain is monitored on an oscilloscope and recorded on an FM tape recorder. In certain instances the simultaneous electromyographic (EMG) activity of various jaw muscles are also monitored on an oscilloscope and recorded on the FM tape recorder. The magnitude and direction of the principal strains are then determined, as well as a root-mean-square analysis of the EMGs. After surface strains have been characterized along different regions of the face (e.g., the postorbital bar, the anterior root of the zygoma, the postcanine alveolar process and basal portions of the mandible), patterns of internal stress are inferred from patterns of surface strain. This is done in order to understand how macaque facial bones dissipate masticatory stress. This work will help explain why primate (including human) facial bones look the way they do. Moreover, by characterizing the mechanical environment of facial bones, these data may provide insights into how and why facial bones respond to various sorts of altered mechanical stress, and thereby contribute to a better understanding of processes related to oral bone loss, skeletal maintenance of mechanical strength, and perhaps growth modification. Explanations for the morphological diversity of the primate face will of necessity, however, involve more than a consideration of mechanical stress and biomechanical scaling. Nevertheless, this morphological diversity frequently has important structural consequences, and it is these consequences toward which this study is directed.