PubMed · 10660355
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
A A Freehafer. 1999. Reconstructive hand surgery.. https://doi.org/10.1038/sj.sc.3100944
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Reaching out to grasp an object (prehension) is a deceptively elegant and skilled behavior. The movement prior to object contact can be described as having two components, the movement of the hand to an appropriate location for gripping the object, the "transport" component, and the opening and closing of the aperture between the fingers as they prepare to grip the target, the "grasp" component. The grasp component is sensitive to the size of the object, so that a larger grasp aperture is formed for wider objects; the maximum grasp aperture (MGA) is a little wider than the width of the target object and occurs later in the movement for larger objects. We present a simple model that can account for the temporal relationship between the transport and grasp components. We report the results of an experiment providing empirical support for our "rule of thumb." The model provides a simple, but plausible, account of a neural control strategy that has been the center of debate over the last two decades.
BACKGROUND: Upper thoracoscopic sympathectomy, obtained either by ablation or resection of the appropriate ganglia, is now the preferred treatment for primary palmar hyperhidrosis. Therefore, we undertook a review to compare the relative efficacy of these two techniques. METHODS: A Medline search was performed for the years 1974-99 to identify all published studies of thoracoscopic sympathectomy for hyperhidrosis. RESULTS: In all, 33 studies were identified and divided into two groups-ablation and resection. When the resection method was used, the immediate success rate was 99.76%, whereas the ablation method achieved dry hands in 95.2% of cases (p = 0.00001). Palmar sweating recurred in 0% of patients treated via resection and -4.4% treated with ablation. Ptosis was noted in 0.92% of cases after ablation and in 1.72% after resection (p = 0.017). CONCLUSIONS: Resection yields superior results, yet the majority of surgeons ablate, probably because it is easier, requires a shorter operating time, leads to fewer cases of Horner's syndrome, and because resympathectomy eventually overcomes initial failure.
The estimation of forces in swimming using the quasi-static approach (Schleihauf, In: J. Terauds, J.P. Clarys (Eds.), Swimming III, International Series on Sports Sciences. Vol. 8, University Park Press, Baltimore, 1979, 70-109) has been popular in recent years as propulsion is an important determinant of performance. The aim of this study was to establish the accuracy and reliability of current and newly proposed procedures for the reconstruction of hand velocity, sweepback angle and pitch angle from underwater three-dimensional video analysis. A full-scale mechanical arm capable of simulating a controlled and highly repeatable underwater phase of the front-crawl stroke was filmed for a set of five trials. A seven-point model of the arm and hand was then digitised at 25 Hz. Hand velocity, sweepback angle and pitch angle were calculated using the procedures of Schleihauf (1979), Berger et al. J. Biomech. 28 (1995) 125-133 and a newly proposed procedure (Lauder). Statistical comparisons were made between procedures to establish their relative accuracy and reliability throughout the stroke. The mean absolute error in measurement of hand velocity between points on the hand was very small (+/- 0.04 and +/- 0.06 m s(-1) in the x and z directions, respectively). The mean errors in sweepback angle and pitch angle were, respectively, 9.3 degrees and 7.6 degrees (Berger), 10.1 degrees and 8.1 degrees (Schleihauf and 10.7 degrees and 7.0 degrees (Lauder). Agreement between procedures showed the standard error between Schleihauf and Lauder to be the least (Schleihauf and Lauder, 0.4 degrees; Berger and Schleihauf, 1.3 degrees; Berger and Lauder; 1.6 degrees). The use of four points in the reconstruction of the orientation of the hand (Schleihauf and Lauder procedures) was shown to be less sensitive to errors in the digitising procedure. The reconstruction procedure proposed in this study (Lauder). further reduced the sensitivity to digitising error in the reconstruction of sweepback and pitch angles in swimming.