胎儿终丝形态学及超微结构研究

Study on the morphology and ultrastructure of fetus ilium terminale

目的观察正常人胎儿终丝形态及其超微结构，为研究脊髓栓系综合征患儿的终丝结构提供参照标准。方法切除并测量11具人新鲜流产胎儿终丝，取其纵、横切面行光镜和扫描电镜观察。结果终丝由1—5μm直径的弹簧样纵向胶原纤维束组成，纤维束呈层分布，每层之间及层内纤维束有空隙。层间隙、束间隙及束内每根纤维间由横向细网状纤维连结，胶原纤维束交叉连结各束间及层间纤维。高倍电镜可见横向纤维及纵向纤维最小单位直径约0．13μm。弹性纤维分散在胶原纤维束内或集中排列在胶原纤维束间。间隙可见少量毛细血管。结论终丝中远段由有序排列的弹簧样纤维结构和少量毛细血管组成的精细三维结构组成，终丝的结构及成分改变可能与脊髓栓系综合征的发病密切相关。

Objective The filum terminale （FT） plays an important role in the pathophysiology of tethered cord syndrome （TCS）. The study on morphology and uhrastructure of fetus FT can provide reference standard for diagnosis of TCS . Method Eleven fresh human aborted fila fetuses had been measured and removed. Transversal and longitudinal sections of the middle, and distal thirds of FT were submitted to light microscopy analysis with four different techniques. Four fila were selected for longitudinal and transversal scanning electron microscopy analysis. Results The bulk of the FT was composed of 1 μm to 5 μm thick spring like longitudinal bundles of collagen separated by 5 μm to 30 μm layer intervals and 1 μm to 5 μm intervals in the layer, although a small quantity of capillaries and other elements may be present. A delicate （0. 13 μm） meshwork of collagen transversal fibers connects these bundles and fibers in every bundle. Collagen bundles could also be found between layers and bundles. Abundant longitudinally oriented elastic fibers were found inside or between collagen bundles. A complex tridimensional structure was evidenced on electron microscopy. Conclusions A complex tridimensional structure composed by ordered arrangement of spring like fibers and small quantity of capillaries should elicit considerable elastic properties to the FT. It＇s alternation of structure and element maybe involved closely in TCS.