Tongue Volume, Function and Biomechanics

描述：舌头在头面部功能、生物力学和生长发育中的作用比较大的颌肌更重要，但受到的关注较少。因此，舌的功能形态和负载的知识是非常初级的。缩小舌体积是治疗各种颅面畸形和疾病的有价值的方法，但这种方法的疗效、功能后果和对生长的影响尚未得到评估。目前的应用是使用一个成熟的猪模型来探索舌头的功能形态，以及它的体积如何影响功能、机械负荷以及减舌手术后对颅面生长的影响。我们建议(目标1)测量舌头在功能过程中的变形，并将这些体积恒定的形状变化与舌肌收缩模式和下巴运动联系起来。我们将使用数字显微超声新技术记录舌头的3D功能性变形，以及舌/颌肌的肌电图和颌骨/头部的运动跟踪。舌头的神经、肌肉和血管组织将用整体组织学来描绘。此外，我们建议(目标2)了解舌头功能变形如何对口腔硬组织产生负荷，以及舌头体积所起的作用。我们将直接测量自然条件下下颌骨、前颌骨和上颌骨的应变和压力，以及电刺激对舌下神经和个别舌肌和颌肌的压力。通过手术缩小舌体体积，以了解舌体体积与功能及后续负荷的关系。最后，为了解决舌体体积减少后恢复和生长效应的主要问题，我们建议(目标3)评估舌体体积减少后的功能后果和生长影响。我们将使用慢性肌电图和X射线透视来跟踪功能恢复，并使用舌/牙模型的纵向测量、系列头影测量、双能X射线吸收测量和组织形态计量学来分析生长情况。整装和免疫组织学将用于评估舌部的神经、肌肉和血管重组，以及手术后缝线和骨骼的成骨细胞复制。这一应用的独特贡献在于描述了舌体在功能过程中的内部变形，阐明了舌体体积如何影响其生物力学载荷，并将这些载荷与功能恢复和颅面生长参数相关联。这些信息的应用将有助于了解正常的舌体功能形态，并评估舌体体积如何影响功能和颅面生长。

DESCRIPTION: The role of tongue in craniofacial function, biomechanics and growth is more critical than the larger jaw muscles but receives less attention. Thus knowledge of tongue functional morphology and loading is very rudimentary. Reducing tongue volume is a valuable approach to treat various craniofacial deformities and disorders, but the efficacy, functional consequences and growth impact following this approach have not been evaluated. The current application is to use a well-established pig model to explore functional morphology of the tongue and how its volume influences function, mechanical loads and the consequences for craniofacial growth following tongue reduction surgery. We propose (Aim 1) to measure tongue deformation during function and relate these volume-constant shape changes to the patterns of contraction in tongue musculature and to the jaw movements. We will record 3D functional deformation of the tongue using the novel technology of digital microsonography, along with electromyography of tongue/jaw muscles and jaw/head movement tracking. The neuromuscular and vascular organization of the tongue will be depicted using whole-mount histology. Further, we propose (Aim 2) to understand how tongue functional deformation produces loads on hard tissues of the oral cavity and what role tongue volume plays. We will make direct measurements of strains and pressures on mandibular, premaxillary and maxillary bones during natural conditions and electrical stimulations to hypoglossal nerves and individual tongue and jaw muscles. Tongue volume will be reduced surgically to understand the relations of tongue volume with function and ensuing loads. Finally, to address the major concerns of recovery and growth effect following tongue volume reduction, we propose (Aim 3) to evaluate the functional consequences and growth impact following tongue volume reduction. We will use chronic electromyography and x-ray fluoroscopy to track functional recovery, and longitudinal measurements of tongue/dental casts, serial cephalometrics, dual energy x-ray absorptiometry and histomorphometry to analyze growth. Whole-mount and immunohistochemical histology will be used for evaluating neuromuscular and vascular reorganization of the tongue and osteogenic cellular replication of sutures and bones after the surgery. The unique contribution of this application is to characterize tongue internal deformation during function, to elucidate how tongue volume influences its biomechanical loads, and to correlate these loads to the parameters of function recovery and craniofacial growth. Application of this information will allow understanding of normal tongue functional morphology and to evaluate how tongue volume affects function and craniofacial growth.