STRAIN IN THE FACIAL BONES OF PRIMATES

这里提出的研究将有助于对功能的理解 灵长类面部区域的形态。灵长类的脸是 以咀嚼器械为主，这项研究将分析 咀嚼力量的性质以及这些力量是如何消散的 穿过灵长类的脸。要遵循的一般方法是 面部活体表面骨应变模式的表征 一种类人灵长类动物--短束猕猴的骨骼。然后，使用各种 各种解剖和生理数据(例如，肌肉形态、颌骨- 运动和/或颌肌肌电数据)，内部的模式 面部的各种(和假定的)结构构件内的应力是 从这些应变数据中推断出。主要目标是确定是否 以及给定的骨骼或骨骼的一部分有多少以及朝哪个方向 在不同的行为中应变，然后使用这些骨骼应变 用于制定和测试各种不同加载模式的假设的数据 面部骨骼。也就是说，确定面部的量和方向 在正常情况下，骨骼弯曲和/或扭曲和/或剪切等 功能。 体内应变将沿着猕猴的面部骨骼进行测量 用应变片测量束状肌。花环应变计(三种应变计 彼此之间具有已知取向的元素)直接结合到 面部骨骼上涂有氰基丙烯酸酯粘合剂。然后猕猴咬了一口 换能器(或咀嚼各种食物)和骨骼应变在 并记录在调频磁带录音机上。在某些情况下 颌骨不同肌肉的同步肌电活动 也在示波器上监视并记录在调频磁带上 录音机。然后，主应变的大小和方向 以及对肌电的均方根分析。之后 表面应变已经沿着不同的区域进行了表征 面部(例如，眼眶后根、颧骨前根、 尖牙后牙槽突和下颌骨的基底部)，图案 从表面应变的模式中推断出内应力的大小。这 是为了了解猕猴面部骨骼是如何消散的 咀嚼压力。 这项工作将有助于解释为什么灵长类(包括人类)的面部骨骼 看看他们做的事情。此外，通过将机械的特性 面部骨骼的环境，这些数据可以提供关于如何和 为什么面部骨骼会对各种变化的机械应力做出反应， 从而有助于更好地理解与以下相关的过程 口腔骨质流失，骨骼保持机械强度，也许 生长修饰。对其形态多样性的解释 然而，灵长类面对的必然不仅仅是一个 考虑机械应力和生物力学比例。 然而，这种形态多样性经常具有重要的 结构性后果，正是这些后果导致了 研究是有针对性的。

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.