Carpal Kinematics During Functional Tasks

描述（由申请人提供）：与工作相关的肌肉骨骼疾病影响上肢是一个重要的和昂贵的国家健康问题。生物力学负荷已被确定为肌肉骨骼疾病发展的关键因素。这一建议的重点是在功能任务期间手腕和远端前臂的骨骼力学。抛镖运动（dart throwwer 's motion， DTM），即腕关节从桡侧伸展到尺侧屈曲，斜向到解剖轴的运动，尽管名字听起来微不足道，但它已被认为是腕关节更重要的功能运动之一，对诸如锤击和投掷等任务至关重要。尸体研究和我们最近的体内研究都表明，投掷镖者的运动是通过腕骨近端排的最小运动来完成的。投掷镖者运动时近端关节缺乏运动，这表明腕中关节必须以其他独特的运动模式进行补偿，尽管迄今为止尚未对此进行研究。本研究的最终目的是评估与工作场所相关的肌肉骨骼损伤相关的高要求任务期间腕骨的变化。我们的第一个目的是确定在模拟锤击任务中手腕和远端尺桡关节（DRUJ）的八个腕骨的运动学（运动和姿势/构象）。在第二个目标中，我们将在尸体模型中检查相同的运动，这将首次允许直接比较体内和体外腕力学。关于上肢的功能和负荷，一个特别有趣的问题是腕骨如何对体内的拉伸负荷作出反应，比如当搬运重物或用扳手拧紧螺栓时产生的拉伸负荷。一种可能性是，由于前臂肌肉的收缩抵消了张力负荷，因此腕骨不受张力负荷的影响。因此，在本提案的第三个目标中，我们将确定在前臂肌肉组织激活和不激活的情况下，拉伸载荷如何影响腕骨。由于在功能加载期间推送任务的重要性，压缩任务也将在第三个目标中进行检查。这项工作的意义在于，它将提供迄今为止无法获得的关于功能性任务期间腕骨和DRUJ机制的体内数据。我们的研究结果将在工作场所人体工程学领域产生深远的影响，并将为医生和科学家制定伤害预防策略和合理的康复方案提供重要的基础科学数据。本研究采用先进的体内成像技术，首次在人类受试者中测量功能任务和负荷对手腕复杂骨骼解剖结构的运动和构象的影响。了解腕骨和前臂远端功能对减少与工作相关的上肢肌肉骨骼疾病至关重要。

DESCRIPTION (provided by applicant): Work-related musculoskeletal disorders affecting the upper extremity are an important and costly national health problem. Biomechanical loading has been identified as a critical factor in the development of musculoskeletal disorders. This proposal focuses on the skeletal mechanics of the wrist and distal forearm during functional tasks. Despite its trivial sounding name, the dart thrower's motion (DTM)-wrist motion from radial extension to ulnar flexion, oblique to the anatomical axes-has been identified as one of the more important functional motions of the wrist, and is critical to tasks such as hammering and throwing. Both cadaver studies and our recent in vivo work suggest that the dart thrower's motion is accomplished with minimal motion of the bones of the proximal row of the carpus. This unique lack of motion of the proximal row during the dart thrower's motion suggests that the midcarpal joints must compensate with other unique patterns of motion, though to date this has not been studied. The ultimate goal of this proposal is to evaluate changes in the carpus during high demand tasks that are associated with workplace related musculoskeletal injury. Our first Aim is to determine the kinematics (motion and posture/conformation) of the eight carpal bones in the wrist and the distal radioulnar joint (DRUJ) during a simulated hammering task. In the second Aim we will examine this same motion in a cadaver model, which for the first time will permit direct comparison of in vivo and in vitro carpal mechanics. An especially intriguing question about the function and loading of the upper extremity is how the carpus responds to tensile loads in vivo, such as those developed when heavy objects are carried or when a wrench is used to tighten a bolt. One possibility is that the carpus is not loaded under tension as contraction of the forearm muscles offsets the tensile loads. Accordingly, in the third Aim of this proposal we will determine how tensile loading affects the carpus, with and without activation of the forearm musculature. A compressive task will also be examined in the third Aim due to the importance of pushing tasks during functional loading. The significance of this work is that it will provide heretofore unavailable in vivo data on the mechanics of the carpus and DRUJ during functional tasks. Our findings will have far reaching implications in the field of workplace ergonomics, and it will provide important basic science data that physicians and scientists can use to develop injury prevention strategies and rational rehabilitation protocols. This proposal uses advanced in vivo imaging techniques to measure, for the first time in human subjects, the effects of functional tasks and loading on the motion and conformation of the complex bony anatomy of the wrist. Understanding how the carpus and distal forearm function is crucial to reducing work-related upper extremity musculoskeletal disorders.