Le Alan, Poukens Vadims, Ying Howard, Rootman Daniel, Goldberg Robert A, Demer Joseph L
Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, California, United States 2Biomedical Engineering Interdepartmental Program, University of California, Los Angeles, California, United States.
Department of Ophthalmology, Stein Eye Institute, University of California, Los Angeles, California, United States.
Invest Ophthalmol Vis Sci. 2015 Oct;56(11):6237-46. doi: 10.1167/iovs.15-17602.
Intramuscular innervation of mammalian horizontal rectus extraocular muscles (EOMs) is compartmental. We sought evidence of similar compartmental innervation of the superior oblique (SO) muscle.
Three fresh bovine orbits and one human orbit were dissected to trace continuity of SO muscle and tendon fibers to the scleral insertions. Whole orbits were also obtained from four humans (two adults, a 17-month-old child, and a 33-week stillborn fetus), two rhesus monkeys, one rabbit, and one cow. Orbits were formalin fixed, embedded whole in paraffin, serially sectioned in the coronal plane at 10-μm thickness, and stained with Masson trichrome. Extraocular muscle fibers and branches of the trochlear nerve (CN4) were traced in serial sections and reconstructed in three dimensions.
In the human, the lateral SO belly is in continuity with tendon fibers inserting more posteriorly on the sclera for infraducting mechanical advantage, while the medial belly is continuous with anteriorly inserting fibers having mechanical advantage for incycloduction. Fibers in the monkey superior SO insert more posteriorly on the sclera to favor infraduction, while the inferior portion inserts more anteriorly to favor incycloduction. In all species, CN4 bifurcates prior to penetrating the SO belly. Each branch innervates a nonoverlapping compartment of EOM fibers, consisting of medial and lateral compartments in humans and monkeys, and superior and inferior compartments in cows and rabbits.
The SO muscle of humans and other mammals is compartmentally innervated in a manner that could permit separate CN4 branches to selectively influence vertical versus torsional action.
哺乳动物水平直肌眼外肌（EOMs）的肌内神经支配是分区的。我们试图寻找上斜肌（SO）存在类似分区神经支配的证据。
解剖三只新鲜牛眼眶和一只人眼眶，以追踪SO肌和肌腱纤维至巩膜附着处的连续性。还从四个人（两名成年人、一名17个月大的儿童和一名33周的死产胎儿）、两只恒河猴、一只兔子和一头牛获取了完整的眼眶。将眼眶用福尔马林固定，整体包埋于石蜡中，在冠状平面上以10μm厚度连续切片，并用马松三色染色法染色。在连续切片中追踪眼外肌纤维和滑车神经（CN4）分支，并进行三维重建。
在人类中，外侧SO肌腹与在巩膜上更靠后附着的肌腱纤维相连，以获得下转的机械优势，而内侧肌腹与在巩膜前方附着的纤维相连，具有内旋的机械优势。猴上斜肌的纤维在巩膜上更靠后附着以利于下转，而下部纤维在巩膜上更靠前附着以利于内旋。在所有物种中，CN4在穿透SO肌腹之前分叉。每个分支支配一个不重叠的眼外肌纤维区，在人类和猴中由内侧和外侧区组成，在牛和兔中由上部和下部区组成。
人类和其他哺乳动物的SO肌以一种方式进行分区神经支配，使得CN4的不同分支能够选择性地影响垂直和扭转动作。
