著者

西中 直也 近 良明 Banks Scott A 三原 研一 鈴木 一秀 大田 勝弘 牧内 大輔 松久 孝行 筒井 廣明 杉本 英治 蒲田 和芳

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.32, no.3, pp.509-512, 2008 (Released:2008-11-21)

参考文献数

16

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The glenoid bare spot commonly is observed in the adult shoulder. Carter et al. proposed that cartilage thickness was affected by normal homeostatic loads. The purpose of this study was to measure glenohumeral translation during shoulder abduction in order to explore development of the glenoid bare spot. 10 healthy shoulders (average 31.1 years old) were studied. 3D models of the scapula and humerus were created from CT scans. Motions were recorded with fluoroscopy during active abduction in neutral rotation for unloaded and a 3kg loaded trial. 3D motions were determined using model-based 3D-to-2D registration. Humeral translation was referenced in the superior/inferior direction to the assumed location of the bare spot (center of the circle described by the bony margins of the inferior glenoid). The bare spot location averaged 4.3mm inferior to the superior/inferior midpoint of the glenoid. Glenohumeral contact was 2.6 and 3.1mm superior to the bare spot for unloaded and loaded conditions with the arm at the side. The humeral head moved upward gradually with abduction to 4mm above the bare spot above 70° abduction (p>0.05, 0 vs 3kg). The glenoid surface stabilizes humeral head translation. Carter et al. suggested that cartilage grew thickest with high mechanical demands (compression and sliding) and thinner where demands were low. Humeral translation away from the bare spot with abduction suggests that lower loads were experienced when the humeral head was near the bare spot and larger loads were experienced with humeral translation away from the bare spot. These kinematic observations were consistent with Carter's framework for cartilage growth and provided a plausible explanation for the development of the glenoid bare spot.

著者

嶋脇 聡 須田 拓也 中林 正隆 杉本 英治

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.862, pp.18-00131, 2018 (Released:2018-06-25)

参考文献数

37

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The neck is an important body part that links the head and chest sections. However, very few analyses of cervical movement derived from muscle contractions have been conducted with numerical simulation. This study aimed to construct a multi-body model of the neck comprising the bones, muscles, and ligaments (including the intervertebral disc) and to apply flexion and extension movements to analyze the behavior of each cervical segment. We created bone models (including cervical vertebrae C1-C7) from X-ray computed tomography (CT) images of the upper half of the human body. Each bone model was bound by 17 types of ligaments constructed as 51 wire models. We set six types of muscles as the protagonists for neck flexion and 12 types for the neck extension. Muscle strength was defined with a parallel contraction element model and an elastic element model. The intervertebral discs represented five spring models with repulsion characteristics on compression and attraction characteristics on extension. The neck section could flex up to 38.1° and extend up to 61.0° with contraction in the flexor and extensor models. The maximum cervical segment angles on flexion and extension were measured at C0-C1 and C4-C5, and their contribution rates were 20.7% and 19.3%, respectively. Each cervical segment angle when flexing and extending closely matched the experimental results measured by other studies. The centers of rotation for cervical segments from C2-C3 to C4-C5 on maximum flexion were different from those in previous experimental result. This may be because of the settings pertaining to the interspinous ligament, nuchal ligament and supraspinous ligament. On the other hand, our results for maximum extension were consistent with past experimental result. An improved neck model will allow the analysis of cervical segment movement through the joint restrictions based on damage to the ligaments and muscles or arthrodesis when flexing and extending.