家兔半膜肌肌构筑、肌内神经和运动终板分布

Muscular architecture and distributions of intramuscular nerves and motor endplates of the semimembranosus in rabbit

目的探究家兔半膜肌的肌构筑与肌内神经和运动终板分布的关系。方法用肌构筑法、改良SihlerWs染色法、乙酰胆碱酯酶染色法对家兔半膜肌肌构筑、肌内神经和运动终板可分布进行观察。结果家兔半膜肌为长肌。肌重(3.31±0.03)g,肌长(5.45±0.09)cm,肌纤维长(3.00±0.01)cm,肌生理横切面积(1.04±0.01)cm2,FL/CSA为2.88,CSA/MW为0.31。支配家兔半膜肌的神经分3条干入肌,即上、中、下干。上干主要支配上1/3的肌束;中干分布到肌的中上部;下干沿途发出的分支最多,司中下部的肌束。中干和下干的分支之间有吻合。肌表面上、中、下部都有线状排列的运动终板短带,尤以肌下部较密。结论家兔半膜肌是长肌,倾向于速度型构筑设计;肌内神经分支密集区,运动终板分布密集;肌内神经和运动终板的分布与肌纤维排列有关。

Objective To investigate the relationship among muscular architecture, distributions of intramuscular nerves and motor endplates of semimembranosus muscle in rabbit. Methods The architecture method, modified sihler＇s staining and acetylcholinesterase staining were used in this study. Results Semimembranosus was a long muscle in rabbit. Muscle weight （MW） was （3.31±0.03）g. Muscle length （ML） was （5.45±0.09） cm. Muscle fiber length （FL） was （3.00±0.01） cm. Physiologic cross- sectional area （CSA） was （1.04±0.01） cm^2. FIMCSA was 2.88. CSA/MW was 0.31. Intramuscular nerves of semimembranosus send out 3 main trtmks in rabbit, they were superior, middle and inferior trtmks. Superior trunk innervated mainly superior 1/3 muscle bundles, middle trunk distributed in middle-superior part; Branches of inferior trunk innervated middle-inferior muscle bundles. Between branches of middle trunk and inferior trunk existed anastomoses. On superior, middle and inferior part of muscle surface, there were many line-arranged motor endplates short bands, the density of which was the highest in inferior part. Conclusion Semimembranosus had relatively high ffi^er length, implying a design towards high excursion and low force production. Dense area of branches of intramuscular nerve, distribution of motor endplates was dense. Distributions of intramuscular nerves and motor endplates of muscle semimembranosus of rabbit were related to spatial arrangement of the muscle fibres.