The role of soft tissues in cranial biomechanics - an investigation using advanced computer modelling techniques

头骨形成一个保护壳，包围着大脑和主要的感觉器官。然而，它不是一个惰性结构。在发育过程中，颅骨组织之间的相互作用有助于塑造成人颅骨结构，即使在成年生活中，骨骼和颅骨软组织之间也会进行密切的对话，继续修改和维持颅骨形状。骨骼会对应变做出反应，无论是来自进食运动/下颌肌肉、颈部肌肉，还是头部血管和其他结构施加的压力。近年来，机械工程软件在生物力学中的应用（我们自己和其他人）增加了我们对日常活动中颅骨所经历的应力水平和分布的理解。然而，很明显，哺乳动物和爬行动物的头骨对类似的压力有不同的反应。这种差异的一部分可能与头骨形状有关-哺乳动物的封闭壳状头骨与许多爬行动物的框架状头骨。然而，这些先前的研究都没有考虑到颅骨解剖学的一个主要组成部分-一方面覆盖颅骨，另一方面被颅骨包围的软组织。头骨和软组织一起组成了一些研究人员认为的“功能矩阵”。我们的目标是检查该矩阵的不同部分的作用，并确定它们是否在哺乳动物和爬行动物的头骨不同。我们的研究小组是跨学科的，在爬行动物和哺乳动物的解剖学和进化，生物力学工程，以及形状与功能的分析的专业知识。我们已经建立了强大的跟踪记录，并开创了一种结合使用动态三维模型（多体动力学分析）和应力分析（有限元分析）的方法。这就产生了详细的、解剖学上精确的动物头骨工作计算机模型，包括关节（移动的和缝合）和肌肉（下巴和脖子）。通过我们以前资助的研究，我们已经建立了一个详细的，解剖学上正确的，动态的爬行动物和哺乳动物的3D模型，其中头骨，缝合，下巴和颈部肌肉组织都被准确地渲染。这些已通过体内分析进行了验证。这些模型将构成新项目的基础，并添加精确渲染的软组织结构，包括骨膜、硬脑膜和颅筋膜;眼眶内容物;大脑;和口腔内容物。解剖工作的数据将通过解剖、对比染色CT扫描和MRI以及筋膜纤维类型和排列的组织学检查生成。

The skull forms a protective shell that encloses the brain and major sense organs. However, it is not an inert structure. During development, the interplay between cranial tissues helps to shape adult skull structure, and even in adult life there is an intimate dialogue between bone and cranial soft tissues that continues to modify and maintain cranial shape. Bone responds to strains, be they from feeding movements/jaw muscles, neck muscles, or the pressures exerted by blood vessels and other structures within the head. In recent years, the application of mechanical engineering software to biomechanics (by ourselves and others) has increased our understanding of the level and distribution of stresses experienced by the skull by everyday activities. However, it has become clear that the skulls of mammals and reptiles respond in different ways to similar stresses. Part of this difference may relate to skull shape - the enclosed shell-like skull of mammals versus the frame-like skull of many reptiles. However, none of these previous studies have taken into consideration a major component of cranial anatomy - the soft tissues that cover the skull on the one hand and are enclosed by it on the other. Together skull and soft tissues make up what some researchers have deemed a 'functional matrix'. Our objective is to examine the role of different parts of that matrix and determine whether they differ in mammal and reptile skulls.Our research group is interdisciplinary, with expertise in reptile and mammalian anatomy and evolution, biomechanical engineering, and the analysis of shape in relation to function. We have established a strong track-record and have pioneered an approach that combines the use of dynamic 3-D models (multibody dynamics analysis) and stress analysis (finite element analysis). This yields detailed, anatomically accurate working computer models of animal skulls, including joints (mobile and sutural) and muscles (jaw and neck). Through our previous funded research, we have built up a collection of detailed, anatomically correct, dynamic 3-D models of reptiles and mammals in which the skull, sutures, and both jaw and neck musculature are accurately rendered. These have been validated with in vivo analysis. These models will form the basis for the new project with the addition of accurately rendered soft tissue structures including periosteum, dura and cranial fascia; orbital contents; brain; and oral contents. The data for the anatomical work will be generated by dissection, contrast-stained CT scanning and MRI, and histological examination of fascial fibre types and arrangement.