Purpose:To compare the acromiohumeral distance (AHD) of both shoulders in subjects with a unilateral shoulder impingement syndrome (SIS) and healthy subjects in a seated position during free shoulder movements of large amplitude. Materials and Methods:Using a 0.5-Tesla SIGNA-SP/i™ open-configuration magnetic resonance imaging (MRI) system, the AHD was measured at several arm positions, in a standardized seated position. Results:In flexion (rest to 130°), the mean AHD of SIS varied from 8.3 to 2.8 mm, as compared to from 8.7 to 4.1 mm for asymptomatic contralateral shoulders. In abduction (rest to 110°), the AHD varied from 8.1 to 3.4 mm and from 8.8 to 4.6 mm for SIS and asymptomatic shoulders, respectively. The smallest AHD (P Ͻ .01) was observed at 110°. From 80°of arm elevation, the AHD was significantly smaller in impingement than in asymptomatic shoulders (P Ͻ .05). The AHD of asymptomatic shoulders did not differ from that of healthy subjects. In SIS, the AHD at rest was correlated with its reduction at all shoulder positions (r p ϭ 0.62-0.88), but was a poor predictor of the smallest AHD observed at 110°(flexion, R 2 ϭ 0.09; abduction, R 2 ϭ 0.08). Conclusion:In the critical arm elevation positions for impingement, AHD is discriminative for SIS, compared to asymptomatic shoulders and healthy ones. AHD at rest is a good indicator of the magnitude of its reduction in elevation, but not of the smallest AHD in arm elevation. ALTHOUGH INTRINSIC TENDON degeneration as a primary cause of rotator cuff rupture is still debated (1,2), one of the factors often proposed to explain the etiology of shoulder impingement syndrome (SIS) and rotator cuff tear is the reduction of the acromiohumeral distance (AHD) during elevation of the arm (3-8). SIS is thought to reflect the painful compression of the supraspinatus tendon, the subacromial-subdeltoid bursa, and/or the long head of the biceps tendon between the humeral head and the acromion (9). Neer (6) even postulated that as many as 95% of rotator cuff tears result from chronic impingement. Studies using scanning electron microscopy also support the idea that degenerative change of the cuff may be aggravated to the extent of a tear by friction and rubbing, irrespective of the initial cause of degeneration (10).In studies where plain conventional radiography was used, an AHD reduction to less than 6 mm is generally agreed to be pathological and indicative of a supraspinatus tendon rupture (12), and patients with an AHD of 7 mm or less, at rest, are likely to have multiple tendon tears (11) or a large cuff tear (5). With magnetic resonance imaging (MRI) in close-bore magnet gantries, which only allow for the evaluation of small shoulder motion and humeral rotations (13,14) in the supine position, evidence was found that the subacromial space of patients with SIS is significantly smaller than that in healthy persons (13). Other studies focused on detecting indirect signs such as osseous and soft-tissue abnormalities that may predispose to rotator cuff impingement (9,(15)(16...

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Abstract. This paper describes a simple, yet efficient method for modelling complex musculo-skeletal structures in motion. The proposed approach contains three main modules: segmentation, 3D reconstruction, and feature extraction. The segmentation module integrates region and edge information in a coherent manner. The 3D reconstruction technique is based on morphological morphing between adjacent slices and on contour-based extrapolation of extreme slices. Model validation is a rather challenging task, since no direct access is possible to in vivo human bony structures of the shoulder complex. We implement an internal validation approach, based on comparing the three models built for the same human shoulder. Finally, two descriptors of the subacromial space deformation during arm motion are computed. Their reliability is assessed using statistics of the healthy human shoulder.

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En vue de mieux comprendre le contexte dans lequel se soulève la problématique de l’exploitation financière des personnes aînées, le présent texte fait ressortir les points saillants de ce phénomène, soit son ampleur, ses manifestations et ses conséquences de même que les principaux moyens envisagés pour lutter contre cette forme de maltraitance. Cet article introductif met également en relief les enjeux et les difficultés que soulèvent les diverses mesures mises en place en vue de détecter, de prévenir et de réprimer les abus financiers à l’égard des aînés. Enfin, ce texte présente l’état de la réflexion des juristes québécois sur cette question et décrit comment le droit appréhende ce phénomène.