Surgical and radiologic anatomy : SRA · 2014
Coaptation/elevation role of the middle deltoid muscle fibers: a static biomechanical pilot study using shoulder MRI.
СтатьяПоддержка исследования: вне правительства СШАНазвание и аннотация: Перевод в очереди
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Hereter Gregori Joan, Bureau Nathalie J, Billuart Fabien, Hagemeister Nicola
Аннотация
PURPOSE: It is generally recognized that the middle deltoid muscle fibers (MDMF) have an elevating effect on the humeral head at small abduction angles. These forces are normally counterbalanced by the coaptation effect of the rotator cuff (RC) muscles to maintain shoulder stability. With RC tears, this balance may be jeopardized leading to shoulder dysfunction. Conversely, not all patients with RC tears develop shoulder dysfunction. The purpose of this study was to investigate the coaptation/elevation forces (CEF) ratio of the MDMF in RC tears subjects and in volunteers, using magnetic resonance imaging (MRI).
METHODS: Magnetic resonance imaging images in 10 subjects with RC tears and in five volunteers were used to build a three-dimensional model of the shoulder. The CEF ratio of the MDMF was estimated by representing the glenohumeral joint as a pulley.
RESULTS: The CEF ratio increased from the posterior to the anterior fibers of the MDMF.The median and interquartile range (IQR) of the CEF ratios of the posterior-third, middle-third, anterior-third and anterior-surface segments of the deltoid were: 0.16 (IQR = 0.23), 0.61 (IQR = 0.4), 1.42 (IQR = 0.41), 1.94 (IQR = 0.56) in subjects, and 0.06 (IQR = 0.24), 0.45 (IQR = 0.28), 1.32 (IQR = 1.01), 1.49 (IQR = 0.39) in volunteers. In the subjects, the CEF ratio of the anterior-surface segment was greater than all other segments (P ≤ 0.03).
CONCLUSIONS: The CEF ratio of the MDMF increased from its posterior segment to its anterior segment, indicating a greater stabilizing effect of the anterior segment both in RC tears subjects and in volunteers. Strengthening of the anterior fibers of the MDMF could potentially improve shoulder function in subjects with RC tears.
METHODS: Magnetic resonance imaging images in 10 subjects with RC tears and in five volunteers were used to build a three-dimensional model of the shoulder. The CEF ratio of the MDMF was estimated by representing the glenohumeral joint as a pulley.
RESULTS: The CEF ratio increased from the posterior to the anterior fibers of the MDMF.The median and interquartile range (IQR) of the CEF ratios of the posterior-third, middle-third, anterior-third and anterior-surface segments of the deltoid were: 0.16 (IQR = 0.23), 0.61 (IQR = 0.4), 1.42 (IQR = 0.41), 1.94 (IQR = 0.56) in subjects, and 0.06 (IQR = 0.24), 0.45 (IQR = 0.28), 1.32 (IQR = 1.01), 1.49 (IQR = 0.39) in volunteers. In the subjects, the CEF ratio of the anterior-surface segment was greater than all other segments (P ≤ 0.03).
CONCLUSIONS: The CEF ratio of the MDMF increased from its posterior segment to its anterior segment, indicating a greater stabilizing effect of the anterior segment both in RC tears subjects and in volunteers. Strengthening of the anterior fibers of the MDMF could potentially improve shoulder function in subjects with RC tears.