Tulane University School of Medicine, New Orleans, Louisiana, USA.
Department of Neurosurgery, Tulane University School of Medicine, New Orleans, Louisiana, USA.
World Neurosurg. 2023 Jul;175:e238-e242. doi: 10.1016/j.wneu.2023.03.059. Epub 2023 Mar 20.
The arterial circle of Willis is a well-known and interconnecting set of blood vessels at the base of the brain. However, its lesser-known venous counterpart, the circle of Trolard, has had almost no attention in the extant medical literature.
Twenty-four adult human brains underwent dissection of the circle of Trolard. When identified, its component vessels and relationships with adjacent structures were confirmed and documented with photography and measured using microcalipers.
A complete circle of Trolard was identified on 42% of specimens. Most (64%) incomplete circles were incomplete anteriorly with no anterior communicating vein. The anterior communicating veins joined the anterior cerebral veins superior to the optic chiasm and continued posteriorly. The anterior communicating veins had a mean diameter of 0.45 mm. The length of these veins ranged from 0.8 mm to 1.45 mm. Thirty-six percent of circles were incomplete posteriorly with lack of a posterior communicating vein. The posterior communicating veins were always larger and longer than the anterior cerebral veins. The posterior communicating veins had a mean diameter of 0.8 mm. The length of these veins ranged from 2.8 to 3.9 cm. In general, the circles of Trolard were more or less symmetrical. However, in 2 specimens, asymmetry existed.
A better understanding of the venous circle of Trolard might decrease iatrogenic injury during approaches to the base of the brain and improve diagnoses based on imaging of the skull base. To our knowledge, this is the first anatomical study dedicated to the circle of Trolard.
Willis 动脉环是大脑底部一组众所周知的相互连通的血管。然而，它鲜为人知的静脉对应物，即 Trolard 环，在现有的医学文献中几乎没有受到关注。
24 个成人头颅进行了 Trolard 环的解剖。当识别出 Trolard 环时，确认了其组成血管与邻近结构的关系，并通过摄影记录下来，使用游标卡尺进行了测量。
在 42%的标本中发现了完整的 Trolard 环。大多数（64%）不完整的环前部不完整，没有前交通静脉。前交通静脉在视交叉上方与大脑前静脉汇合，并向后继续。前交通静脉的平均直径为 0.45 毫米。这些静脉的长度范围为 0.8 毫米至 1.45 毫米。36%的环后部不完整，缺乏后交通静脉。后交通静脉总是比大脑前静脉更大更长。后交通静脉的平均直径为 0.8 毫米。这些静脉的长度范围为 2.8 厘米至 3.9 厘米。总的来说，Trolard 环或多或少是对称的。然而，在 2 个标本中存在不对称。
更好地了解 Trolard 静脉环可能会减少对大脑底部入路的医源性损伤，并改善基于颅底成像的诊断。据我们所知，这是第一项专门针对 Trolard 环的解剖学研究。
