大鼠坐骨神经显微解剖及其意义

Micro anatomy of the sciatic nerve of the adult rat and its significance

目的研究大鼠坐骨神经显微解剖结构，探讨其对建立大鼠失神经支配腓肠肌模型的意义。方法先对６０只大鼠１２０条坐骨神经进行完整显微解剖学观察；再将４８只大鼠坐骨神经在不同平面切断，建立失神经支配腓肠肌实验模型，观察肢体溃疡情况，测量腓肠肌湿重及肌细胞直径。结果１．大鼠坐骨神经主要由腰４，５，６及骶１神经根组成；血供来自臀下动脉，阴内、外侧动脉，股动脉穿支及动脉分支；在坐骨结节、大腿中１／３及下１／３平面的横径及前后径分别为１．５４ｍｍ、１．５３ｍｍ、１．５２ｍｍ及０．９１ｍｍ、０．８９ｍｍ、０．８８ｍｍ；胫神经逆行可分离长度及强行分离长度分别为１．５ｃｍ及２．０ｃｍ；腓肠肌由胫后神经内、外侧肌支支配。２．在坐骨结节平面、大腿下１／３切断坐骨神经主干及切断胫神经，肢体溃疡发生率分别为３３．３％、２５％及８．３％，切断腓肠肌支无溃疡发生；各组腓肠肌湿重及肌细胞直径无显著性差异，Ｐ＞０．０５。结论大鼠坐骨神经是建立周围神经损伤与修复的良好实验模型，在建立失神经支配骨骼肌模型时。

Objective To investigate the micro anatomy of the sciatic nerve of adult rats and to probe its significance in the established model of denervated gastrocnemius muscle. Methods Micro dissection and observation were done in 120 sciatic nerves of 60 rats and sciatic nerves of another 48 rats were sectioned at different levels to observe the occurrence of ulcers in the affected limbs and measured the wet weight of the corresponding gastrocnemius and the diameter of the muscle cells. Results 1. The sciatic nerve was composed of the fourth, fifth and sixth lumbar and the first sacral nerve roots. The blood circulation was supplied by inferior gluteal artery, internal and external pudendal artery, perforating branches of femoral artery and popliteal artery. The mean transverse and anterior posterior diameters of sciatic nerve at the levels of ischial tuberosity, middle one third and lower one third of the thigh were 1.54mm, 1.53mm, 1.52mm and 0.91mm, 0.89mm, 0.88mm respoectively. The retrograde dissection length of tibial nerve was 1.5cm and forced dissection length was 2.0cm. The gastrocnemius muscle was innervated by the medial and lateral muscular branches of the posterior tibial nerve. 2. The limb ulceration rates were 33.3%, 25% and 8.3% in the groups of sciatic nerve sectioned at the levels of ischial tuberosity, lower one third of the thigh and tibial nerve section respectively. There was no ulceration in the group of which the nerve to the gastrocnemius was sectioned. There were no signifiicant differences of the muscle wet weight and the muscle cell diameter in all three groups. Conclusion The sciatic nerve of adult rat can well be used for experimental peripheral nerve injury and repair model, while in establishing a model of denervated skeletal muscle, either sectioning of tibial nerve or its branch to the muscle would be more appropriate. (Shanghai Med J, 1999,22:154 156)