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

浜田 純一郎 山口 光國 筒井 廣明 前田 健 近 良明

出版者

日本肩関節学会

雑誌

肩関節 (ISSN:09104461)

巻号頁・発行日

vol.36, no.2, pp.725-729, 2012 (Released:2012-10-25)

参考文献数

6

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Background: The understanding of the glenohumeral (GH) joint motion during baseball pitching should be necessary for diagnosis and treatment for throwing shoulder. The purposes of this study were firstly to investigate the motions of the scapula, pelvis, upper body, and upper limbs and secondly to speculate the motion of the GH joint and the scapula from the top position to ball release.Methods: We observed the pitching of 2 professional and 2 high-level amateurs with a digital camera and a video camera, recording each motion of the pelvis, upper body, scapula, and upper limbs. We classified pitching motion into 3 phases which were slide, upper body rotation, and arm throwing in order to simply analyze the motion in each phase.Results: Each scapula protracted and retracted respectively during pitching motion. The pelvis which was closed in the stride, ball release, and follow-through synchronized with scapular motion. The throwing arm moved in the scapular plane and made the elbow extend to the ball release. Internal rotation of the humeral head was a little from the top position to the ball release.Discussion: Both scapula and pelvis synchronized at each phase of pitching motion. The motion of the GH joint was speculated to be a small amount from the top position to ball release.