Overuse syndrome?
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Biomedical subjects
Publications and source records attributed to D Ranney.
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A method of describing the musculoskeletal loads in the hand and wrist during manual tasks is presented. A profile of twelve factors is used to quantify the exposure of applicable soft tissues to modes of loading suggested as being related to a number of chronic, work-related musculoskeletal disorders such as chronic muscle strain, tenosynovitis, and carpal tunnel syndrome. These factors include estimates of tendon loads and movement, frictional work done on the tendon sheaths, and muscle activation determined using electromyography. The response of these measures to changes of force, repetition, and posture was studied using eight conditions of a simulated task utilizing a pistol grip tool. Measures of tendon frictional work and dynamic electromyographic activity best paralleled the injury outcomes of an epidemiological study using similar task definitions (Silverstein et al. 1986). This field-usable system is being used currently to investigate the relationship between occupational exposure and musculoskeletal disorders.
A new linear array test tool is presented. It is easily used to directly measure an image acquisition parameter: the transmit/receive aperture. The aperture measurement gives important information concerning the functioning of the real-time multielement transducer and the equipment's signal-processing hardware and software. A feasibility test of the new test tool demonstrated that it can be easily used by clinical personnel to (1) determine the variation of the transmit/receive aperture with image depth; (2) document the operation of the equipment in each of the operator selectable focusing schemes; (3) perform quick checks of equipment performance when in doubt; and (4) test for and document the existence of nonfunctioning elements in linear, curved linear (convex), and phased arrays.
The lumbrical muscle is clearly one of several possible extensors of the interphalangeal joints. With an origin on the flexor digitorum profundus tendon it is credited with unloading the elastic tension across the interphalangeal joints and thereby facilitating their extension. Its role at the metacarpophalangeal joint is not a matter of universal agreement. Attempts to simulate its action with weights over pulleys have not clarified this role, since true simulation would require the development of a means of applying force along the course of the lumbrical without pre-determining which end would move. Such a system is herein described; it uses a Bowden cable, which is commonly used to activate the brakes of a bicycle. After constructing length-tension curves of the profundus muscle in four fresh cadavers prior to the onset of rigor mortis, the interaction of realistic lumbrical loads with profundus elastic tension was studied. By contraction a lumbrical muscle adds a small but significant flexor force at the metacarpophalangeal joint, and thereby it is also capable of contributing to radial deviation and possibly rotation. As it runs from a flexor tendon to an extensor tendon and is endowed with a great many muscle spindles, the lumbrical could play a part in the control of finger movement by monitoring the rate of hand closing during grasp.