Three-dimensional location of human rectus pulleys by path inflections in secondary gaze positions.
Three-dimensional location of human rectus pulleys by path inflections in secondary gaze positions.
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发表时间：
2000-11
影响因子：
4.4
通讯作者：
R. Clark;Joel Miller;J. Demer
中科院分区：
文献类型：
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作者：
R. Clark;Joel Miller;J. Demer
目的结缔组织滑车是眼外肌的功能性机械起点。在这些滑轮之前，眼外肌路径随着注视而移动以跟随巩膜插入，而后眼外肌路径在眼眶中稳定。由注视移位产生的EOM路径中的拐点可用于在三维（3-D）中定义滑轮的功能位置。方法对11例正常成人22个眼眶进行垂直于眶轴的连续磁共振成像，观察眼球在中心注视、上仰、下仰、外展和内收状态下的前后方向变化。在每个眼外肌的长度上绘制以标准化眼中心坐标系表示的平均眼外肌横截面积质心，以确定路径。确定路径拐点以在3-D中定义滑轮位置。结果所有眼外直肌眼外肌路径在次级注视位置均表现出明显的屈曲，距地球仪中心后3 ~ 9 mm，这在受试者中是一致的。地球仪中心和外侧直肌滑轮在眼眶内系统平移，并伴有外侧注视，而其他滑轮相对于眼眶保持稳定。结论：眼外肌直肌路径在第二注视位置的明显弯曲证实了滑轮的存在，并确定了它们在3-D中的位置。地球仪和外直肌滑车随注视位置系统平移。EOM滑轮可以通过实现可交换的眼睛运动设备来简化眼睛运动的神经控制，在所述可交换的眼睛运动设备中，用于3-D眼睛速度的命令有效地独立于眼睛位置。
PURPOSE Connective tissue pulleys serve as the functional mechanical origins of the extraocular muscles (EOMs). Anterior to these pulleys, EOM paths shift with gaze to follow the scleral insertions, whereas posterior EOM paths are stable in the orbit. Inflections in EOM paths produced by gaze shifts can be used to define the functional location of pulleys in three dimensions (3-D). METHODS Contiguous magnetic resonance images in planes perpendicular to the orbital axis spanned the anteroposterior extents of 22 orbits of 11 normal adults with the eyes in central gaze, elevation, depression, abduction, and adduction. Mean EOM cross-sectional area centroids represented in a normalized, oculocentric coordinate system were plotted over the length of each EOM to determine paths. Path inflections were identified to define pulley locations in 3-D. RESULTS All rectus EOM paths exhibited in secondary gaze positions distinct inflections 3 to 9 mm posterior to globe center, which were consistent across subjects. The globe center and the lateral rectus pulley translated systematically in the orbit with lateral gaze, whereas other pulleys remained stable relative to the orbit. CONCLUSIONS Distinct inflections in rectus EOM paths in secondary gaze positions confirm the existence of pulleys and define their locations in 3-D. The globe and lateral rectus pulley translate systematically with gaze position. The EOM pulleys may simplify neural control of eye movements by implementing a commutative ocular motor plant in which commands for 3-D eye velocity are effectively independent of eye position.