共查询到20条相似文献,搜索用时 31 毫秒
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A. McEwen Smith 《BMJ (Clinical research ed.)》1946,2(4479):694-695
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Louise Diederichsen Michael Krogsgaard Michael Voigt Poul Dyhre-Poulsen 《Journal of electromyography and kinesiology》2002,12(3):183-191
Dynamic shoulder stability is dependent on muscular coordination and sensory inputs. In the shoulder, mechanoreceptors are found in the coracoacromial ligament, the rotator cuff tendons, the musculotendinous junctions of the rotator cuff and in the capsule. The number of receptors in the capsule is small compared to the number in the other shoulder structures. Proprioceptive information from numerous receptors in muscles and tendons is mediated via fast conducting nervefibers and probably contribute more to kinaestethic sensation than information from capsule and ligaments. Therefore it seems likely that the joint receptors have a more distinct role for the kinaestethic sense than muscle receptors. In cats a direct reflex from the afferents innervating the shoulder to the muscles around the shoulder has been presented. The reflex had an extremely short latency (2.7-3.1 ms). In man, a very long latency (300 ms) excitatory reflex has been found when nerves in the capsule were stimulated electrically during shoulder surgery. In addition, when the anterior-inferior capsule was excited in conscious humans with modest amplitude electrical stimuli during muscle activity, a strong inhibition was found with an average latency of 33 ms. Stimulation of the sensory nerves in the coracoacromial ligament has also been found to modify muscle activity strongly. Even though our understanding of the control of shoulder motion is incomplete, it is clear that sensory inputs can strongly modify muscle activity around the shoulder. This has implications for rehabilitation and shoulder surgery. 相似文献
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Heneage Ogilvie 《BMJ (Clinical research ed.)》1946,1(4444):362-363
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陶敏华 《上海生物医学工程》2010,(3):172-174
目的分析肩难产发生原因,对母婴的影响,处理及预防。方法对我院1988年1月~2006年12月住院分娩产妇中出现的15例肩难产病例进行回顾性总结分析。结果肩难产虽然发生率低,但一旦发生即会造成较严重的分娩并发症,并对母婴产生严重危害,甚至新生儿死亡。结论巨大儿常发生肩难产。肩难产处理不当会发生严重的母婴并发症。产科医师除熟练掌握处理肩难产的各种方法外,更要做产前防范与助产的技巧把握。 相似文献
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Reverse total shoulder arthroplasty was initially approved for use in rotator cuff arthropathy and well as chronic pseudoparalysis without arthritis in patients who were not appropriate for tendon transfer reconstructions. Traditional surgical options for these patients were limited and functional results were sub-optimal and at times catastrophic. The use of reverse shoulder arthroplasty has been found to effectively restore these patients function and relieve symptoms associated with their disease. The procedure can be done through two approaches, the deltopectoral or the superolateral. Complication rates associated with the use of the prosthesis have ranged from 8-60% with more recent reports trending lower as experienced is gained. Salvage options for a failed reverse shoulder prosthesis are limited and often have significant associated disability. Indications for the use of this prosthesis continue to be evaluated including its use for revision arthroplasty, proximal humeral fracture and tumor. Careful patient selection is essential because of the significant risks associated with the procedure.Download video file.(61M, mov) 相似文献
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Holger Preuschoft Bianca Hohn Heike Scherf Manuela Schmidt Cornelia Krause Ulrich Witzel 《International journal of primatology》2010,31(2):301-320
Studies of the shoulder girdle are in most cases restricted to morphological comparisons and rarely aim at elucidating function
in a strictly biomechanical sense. To fill this gap, we investigated the basic functional conditions that occur in the shoulder
joint and shoulder girdle of primates by means of mechanics. Because most of nonhuman primate locomotion is essentially quadrupedal
walking—although on very variable substrates—our analysis started with quadrupedal postures. We identified the mechanical
situation at the beginning, middle, and end of the load-bearing stance phase by constructing force parallelograms in the shoulder
joint and the scapulo-thoracal connection. The resulting postulates concerning muscle activities are in agreement with electromyographical
data in the literature. We determined the magnitude and directions of the internal forces and explored mechanically optimal
shapes of proximal humerus, scapula, and clavicula using the Finite Element Method. Next we considered mechanical functions
other than quadrupedal walking, such as suspension and brachiation. Quadrupedal walking entails muscle activities and joint
forces that require a long scapula, the cranial margin of which has about the same length as the axillary margin. Loading
of the hand in positions above the head and suspensory behaviors lead to force flows along the axillary margin and so necessitate
a scapula with an extended axillary and a shorter cranial margin. In all cases, the facies glenoidalis is nearly normal to
the calculated joint forces. In anterior view, terrestrial monkeys chose a direction of the ground reaction force requiring
(moderate) activity of the abductors of the shoulder joint, whereas more arboreal monkeys prefer postures that necessitate
activity of the adductors of the forelimb even when walking along branches. The same adducting and retracting muscles are
recruited in various forms of suspension. As a mechanical consequence, the scapula is in a more frontal, rather than parasagittal,
position on the thorax. In both forms of locomotion—quadrupedal walking and suspension—the compression-resistant clavicula
contributes to keeping the shoulder complex distant from the rib cage. Future studies should consider the consequences for
thorax shape. The morphological specializations of all Hominoidea match the functional requirements of suspensory behavior.
The knowledge of mechanical functions allows an improved interpretation of fossils beyond morphological similarity. 相似文献
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J. K. Lipman 《The Western journal of medicine》1992,156(3):299-300
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I. V. Vereshchaka A. V. Gorkovenko V. I. Khorevin A. N. Tal’nov V. V. Korneyev A. I. Kostyukov 《Neurophysiology》2011,42(4):265-275
We studied central motor commands, CMCs, coming to the muscles that flex and extend the shoulder and elbow joints in the course
of generation of voluntary isometric efforts of different directions by the forearm; the efforts were initiated according
to a visual signal. Amplitudes of EMGs recorded from the muscles of the shoulder belt and shoulder and subjected to full-wave
rectification and low-frequency filtration were considered correlates of the CMC intensity. An effort of the preset direction
was developed within the operational space of the horizontal plane with angles 30 deg in the shoulder joint (external angle
with respect to the frontal plane) and 90 deg in the elbow joint. We plotted sector diagrams of the logarithmic coefficient
of the intensity increment of EMGs of the above muscles for the entire set of directions of generated efforts with a 15- or
20-deg step. Orientations of the maxima of EMG activity of the given muscles were rather close to the directions of the maxima
of the force moments generated by these muscles. In most cases, a shift of the direction by one gradation with respect to
the EMG maximum in the respective muscle resulted in a significant decrease in the level of EMG activity. It is shown that
preferential activation of the muscles agonistic with respect to the examined direction of the generated effort was, as a
rule, accompanied by coactivation of the antagonist muscles. When “two-joint” isometric efforts are formed, realization of
the socalled synergic muscle tasks (where prevailing contractions of the muscles of the same functional direction for both
joints coincide, i.e., flexion-flexion or extension-extension) is organized in a simpler manner. The programs of “nonsynergic”
contractions (flexion of one joint and extension of another one, or vice versa) are more complex. In different subjects, considerably dissimilar patterns of EMG activity in muscles influencing these joints
could be observed. 相似文献