扫描电镜下缢沟的形态特征

A STUDY OF THE HANGING LIGATURE MARKS UNDER SEM

作者用光镜和扫描电镜对縊沟进行对比观察,得出如下结论:(1)扫描电镜下縊沟组织的改变具有较恒定的特征,出血及纤维蛋白检出率远较光镜为高;(2)在光镜下生活反应不明显的生前缢沟,在扫描电镜下其表面及断面均可见红细胞及纤维蛋白形成,并包裹红细胞。縊沟部位胶原纤维之间可见散在大小不等的圆球形脂肪样小滴。缢沟部位肥大细胞的形态改变,有助于生前与死后缢沟的鉴别诊断。

The present study aims at observation of the mast cells, fibrin network formation and hemorrhage on the cryofracture surface of the ligature mark as well as on their superficial surface under both SEM and light microscope. Ligature marks from 12 antemortem and 2 postmortem hanging cases were studied.The morphologic changes of antemortem ligature marks under SEM were as follows. (1) In case of either hard or soft ligature marks, the squamous epithelial cells were detached and aggregated; (2) Most epithelial cells were disarranged. Their nuclear became elongated and cellular margins were obscured; (3) In severe injured area, the collagen fibers and the capillaries of the dermis were exposed. Some collagen fibers were fused eachother; (4) The hairs were compressed. Some of the hair roots were exposed. The hair follicles were deformed and their cellular junctions were loosened;(5) On both superficial and fracture surfaces, hemorrhage and fibrin network formation embeded with RBC were seen; (6) Among the collagen fibers, there were many fat-like droplets 2～48μ in diameter; (7) In some area, various kinds of morphologic changes of mast cells accompanied by degranulation were observed. The number of heterochromous mast cells on the antemortem marks was less than that on both sides of the marks by Toluidine Blue staining. The significance of this finding remains to be solved. In postmortem marks, hemorrhage, fibrin formation and fat-like droplets among the collagen fibers were not observed. The number of mast cells did not decrease on Toluidine Blue staining section. All these findings suggest that the morphologic changes of ligature marks under SEM are helpful for the differential diagnosis of the antemortem marks from the postmortem marks.