Happak W, Liu J, Burggasser G, Flowers A, Gruber H, Freilinger G
Department of Surgery, University of Vienna, Austria.
Anat Rec. 1997 Oct;249(2):276-84. doi: 10.1002/(SICI)1097-0185(199710)249:2<276::AID-AR15>3.0.CO;2-L.
Extrafusal muscle fibers of human striated skeletal muscles are known to have a uniform innervation pattern. Motor endplates (MEP) of the "en plaque" type are located near the center of muscle fibers and distributed within the muscles in a narrow band. The aim of this study was to evaluate the innervation pattern of human facial muscles and compare it with that of skeletal muscles.
Ten facial muscles from 11 human cadavers were dissected, the nerve entrance points located, and the dimensions measured. All muscles were stained in toto for MEPs using Acetylcholinesterase (AChE) and examined under the microscope to determine their location. Single muscle fibers were teased to evaluate the stained MEPs.
The length of the different facial muscles varied from 29 to 65 mm, which correlated to the length of the corresponding muscle fibers. MEP zones were found on the muscles in the immediate vicinity of the nerves' entrance points and located eccentrically. Numbers and locations varied from muscle to muscle. Three MEP zone distribution patterns were differentiated: numerous small MEP zones were evenly spread over the muscle, a predominant MEP zone and two to three small zones were spread at random, and two to four MEP zones of equal size were randomly scattered. One MEP of the "en plaque" type was found in 73.8% of the muscle fibers and two to five MEPs were found in 26.2%. The distances between the multiple MEPs on one muscle fiber varied from 10 to 500 microm.
This study suggests that facial muscles differ from skeletal muscles regarding distribution and number of MEPs. The eccentric location of MEP zones and multiple MEPs suggests there is an independent mechanism of neural regulation in the facial muscle system.
已知人类横纹肌的梭外肌纤维具有统一的神经支配模式。“板状”型运动终板（MEP）位于肌纤维中心附近，并在肌肉内呈窄带状分布。本研究的目的是评估人类面部肌肉的神经支配模式，并将其与骨骼肌的神经支配模式进行比较。
解剖11具人类尸体的10块面部肌肉，确定神经入口点并测量其尺寸。所有肌肉均用乙酰胆碱酯酶（AChE）对MEP进行整体染色，并在显微镜下检查以确定其位置。分离单根肌纤维以评估染色的MEP。
不同面部肌肉的长度在29至65毫米之间变化，这与相应肌纤维的长度相关。在神经入口点紧邻的肌肉上发现了MEP区，且位于偏心位置。数量和位置因肌肉而异。区分出三种MEP区分布模式：许多小MEP区均匀分布在肌肉上，一个主要的MEP区和两到三个小区域随机分布，以及两到四个大小相等的MEP区随机散布。在73.8%的肌纤维中发现一个“板状”型MEP，在26.2%的肌纤维中发现两到五个MEP。一根肌纤维上多个MEP之间的距离在10至500微米之间。
本研究表明，面部肌肉在MEP的分布和数量方面与骨骼肌不同。MEP区的偏心位置和多个MEP表明面部肌肉系统存在独立的神经调节机制。
