Stone E A, Stewart G J
Thrombosis Research Center, Temple University Medical School, Philadelphia, Pennsylvania 19140.
Anat Rec. 1988 Oct;222(2):154-63. doi: 10.1002/ar.1092220207.
The occurrence of cell-infiltrated intimal lesions at the confluence of many small tributaries with canine jugular and femoral veins suggested that these areas (confluences) might 1) differ structurally from the rest of the receiving vein and 2) serve as initiation sites for thrombi. To explore these possibilities, the number of tributaries was determined by careful blunt dissection, and the architecture of confluences was studied by light and scanning and transmission electron microscopy. In addition to confluences formed by a named tributary (omobrachial), canine jugular veins averaged 11 confluences formed with small (0.2 to 2.5 mm diameter) unnamed tributaries that had not been previously described. Femoral veins averaged eight confluences of which four were formed with small unnamed tributaries. Double-leafed valves were found at 90% of jugular and 76% of femoral vein confluences. Previously such valves were described only at the confluence of superficial with deep leg veins. Corrosion casts of iliac, saphenous, azygous, costocervical, and maxillary veins as well as cranial and caudal vena cava demonstrated a similar pattern of tributaries and valves. The three structures (receiving vein, tributary, valves) that formed the confluence differed, necessitating considerable modification as they approached the area of fusion. Jugular and femoral vein walls contained 5 to 10 layers of smooth muscle, abundant collagen, and a small amount of elastin. Tributary walls contained 0 to 2 discontinuous smooth muscle cell layers, limited collagen, and no elastin. As receiving veins approached a confluence, the thickness decreased by 15 to 77% except at valve attachment sites, which were thickened. A cluster of smooth muscle cells formed the junction of valve leaflets with vein. Endothelium was continuous over the luminal surface of all three structures. Calculations showed that these small-valved tributaries make only a small contribution to venous return. On the other hand, there is considerable information to support the concept that local attenuation of the vein wall would lead to localized vessel dilation, resulting in rupture of the endothelium and basement membrane.
在犬类颈静脉和股静脉的许多小支流汇合处出现细胞浸润性内膜病变，这表明这些区域（汇合处）可能：1）在结构上与接受静脉的其余部分不同；2）作为血栓的起始部位。为了探究这些可能性，通过仔细的钝性解剖确定支流的数量，并通过光学显微镜、扫描电子显微镜和透射电子显微镜研究汇合处的结构。除了由一条命名支流（臂下静脉）形成的汇合处外，犬类颈静脉平均有11个汇合处是与先前未描述的小（直径0.2至2.5毫米）无名支流形成的。股静脉平均有8个汇合处，其中4个是与小无名支流形成的。在90%的颈静脉汇合处和76%的股静脉汇合处发现了双叶瓣膜。以前，这种瓣膜仅在小腿浅静脉与深静脉的汇合处被描述过。髂静脉、隐静脉、奇静脉以及颈肋静脉、上颌静脉以及头侧和尾侧腔静脉的铸型显示出类似的支流和瓣膜模式。形成汇合处的三个结构（接受静脉、支流、瓣膜）各不相同，在接近融合区域时需要进行相当大的改变。颈静脉和股静脉壁含有5至10层平滑肌、丰富的胶原蛋白和少量弹性蛋白。支流壁含有0至2层不连续的平滑肌细胞层、有限的胶原蛋白且无弹性蛋白。当接受静脉接近汇合处时，厚度除了在瓣膜附着部位（增厚）外会减少15%至77%。一群平滑肌细胞形成瓣膜小叶与静脉的连接处。内皮在所有三个结构的管腔表面是连续的。计算表明，这些有小瓣膜的支流对静脉回流的贡献很小。另一方面，有大量信息支持这样的概念，即静脉壁的局部变薄会导致局部血管扩张，从而导致内皮和基底膜破裂。
