Upper extremities applications

In implantable stimulators and electrodes, the stimulation parameters greatly depend on the implantation site. When the electrodes are positioned on or around the target nerve, the stimulation amplitudes are on the order of a few milliamperes or less. Electrodes positioned on the muscle surface (epimysial electrodes) or in the muscle itself (intramuscular electrodes), employ up to ten times higher amplitudes. For muscle force control, implantable stimulators rely either on pulse-width modulation or amplitude modulation. For example, in upper extremity applications, the current amplitude is usually a fixed parameter set to 16 or 20 mA, while the muscle force is modulated with pulse widths within 0-200 p,s. 

In 2005 and 2007 (Phase 2), a more recent study for the U. S. Marine Corps, by Hill et al., evaluated 13 self-applied tourniquets for their applicability in combat applications. This study attempted to measure the functionality of the candidate tourniquets in battlefield conditions by immersing them in a simulated blood/sand mixture prior to testing. In contrast to the earlier Army study by Walters et al., the conclusion drawn from this study was the recommendation that one of the ratcheting or stretch-retention type tourniquet systems be adopted for combat deployment. These types had the best user subjective ratings as well as the lowest application times especially on the upper extremities where one-handed application was required. The recommended group had application times 30-50% lower on the upper extremities than the windlass types recommended by the Army study. Velcro was observed to lose its effectiveness as a clamp when it became fouled with wet sand or mud and, therefore, should be avoided. It should be noted that none of the tourniquet types used in the Marine Corps study were pneumatic. 

A risk factor is defined as an attribute or exposure that increases the probability of a disease or disorder (Putz-Anderson, 1988). Biomechanical risk factors for musculoskeletal disorders include repetitive and sustained exertions, awkward postures, and application of high mechanical forces. Vibration and cold environments may also accelerate the development of musculoskeletal disorders. Typical tools that can be used to identify the potential for development of musculoskeletal disorders include conducting work-methods analyses and checklists designed to itemize undesirable work site conditions or worker activities that contribute to injury. Since most of manual work requires the active use of the arms and hands, the structures of the upper extremities are particularly vulnerable to soft tissue injury. WUEDs are typically associated with repetitive manual tasks with forceful exertions, such as those performed at assembly lines, or when using hand tools, computer keyboards and other devices, or operating machinery. These tasks impose repeated stresses to the upper body, that is, the muscles, tendons, ligaments, nerve tissues, and neurovascular structures. There are three basic types of WRDs to the upper extremity tendon disorder (such as tendonitis), nerve disorder (such as carpal tunnel syndrome), and neurovascular disorder (such as thoracic outlet syndrome or vibration-Raynaud s syndrome). The main biomechanical risk factors of musculoskeletal disorders are presented in Table 22. 

This chapter is intended to illustrate the application of some principles and practices of human performance engineering, especially quantification of human performance in the field of occupational medicine. I have selected the problem of low back pain to illustrate a series of concepts that are essential to evaluation of both the worker and the workplace, while reahzing the importance of the disorders of the neck and upper extremities. By inference and generalization, most of these concepts can be extended to these situations. 

Knutson J.S., Naples G.G., Peckham P.H., and Keith M.W 2002. Fracture rates and occurrences of infection and granuloma associated with percutaneous intramuscular electrodes in upper extremity functional electrical simulation applications. Rehab. Res. Dev. 39 671-684. 

Memberg, W, Peckham, P.H., Thorpe, G.B., Keith, M.W, and BQcher, T.R 1993. An analysis of the reh-ability of percutaneous intramuscular electrodes in upper extremity FNS applications. IEEE Trans. Biomed. Eng. 1 126. 

Peterson, D. R., A Method for Quantifying the Biodynamics of Abnormal Distal Upper Extremity Function Application to Computer Keyboard Typing, Ph.D. Dissertation, University of Connecticut, 1999. 

At the upper extreme of the molecular mass scale, AT must be lowered instead of raised, which simply requires an appropriate reduction in the heat input. Since thermal FFF appears to have some important advantages for ultrahigh molecular mass polymers (among them the lack of shear degradation), this subject is an important one in the context of thermal FFF applications. 

Test procedure, (i) The side-load application shall be at the upper extremity of the frame upright at a 90° angle to the centerline of the vehicle. The side load L shall be applied according to Figure W-16. L and D shall be recorded simultaneously. The test shall be stopped when ... 

Static and dynamic rear load application shall be distributed uniformly along a maximum projected dimension of 27 in. (686 mm), and a maximum area of 160 sq. in. (1,032 sq. cm), normal to the direction of load application. The load shall be applied to the upper extremity of the frame at the point that is midway between the centerline of the seat and the inside of the frame upright. 

Practical Applications and Case Histories of the Upper Extremities... 

This Handbook is organized into three main sections. The first section, which consists of three chapters, reviews the basic scientific, engineering, and clinical foundations for UHMWPE. For example, in Chapter 2, we explain how UHMWPE must be formed into bulk components from the resin powder using extrusion or compression molding techniques. In Chapter 3, we review the techniques associated with sterilization and packaging of UHMWPE implants. Chapters 5-12 cover the basic clinical applications of UHMWPE in the lower extremities, upper extremities, and the spine. 

The technical definition of a tourniquet is any device that is used to prevent blood from flowing through blood vessels below the placement of the tourniquet on either upper or lower limbs. A tourniquet prevents excessive loss of blood from a limb wound with the expectation of saving a life. On the battlefield, the tourniquet in one form or another has been used to control excessive hemorrhaging on nonvital extremities since the Roman Empire days, where a rope or cloth strap was used for toumiqueting a soldier s limb that has suffered a wound. The use of tourniquets has always been as controversial as it has been successful. This controversy results, as will be described later, as much from mistakes made in the application and release of the tourniquet as it does from the primitive design of the most commonly used tourniquets of today. 

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