Division of Anatomy, Faculty of Stomatology, "Carol Davila" University of Medicine and Pharmacy, 8 Eroilor Sanitari Blvd., 050474, Bucharest, Romania.
Surg Radiol Anat. 2023 Jun;45(6):761-763. doi: 10.1007/s00276-023-03145-4. Epub 2023 Apr 17.
Anatomic variations at the junction of primitive internal carotid and basilar arteries are exceedingly rare. We aimed at reporting such rare variants involving the posterior communicating artery (PComA) and the P1 segment of posterior cerebral artery (PCA).
The circle of Willis was dissected in an adult cadaver after removal of the cranial vault and cerebral hemispheres.
The basilar end was rotated axially to the right. The P1 segment of the right PCA was fenestrated and occupied the interpeduncular fossa. The right PComA passed over the oculomotor nerve to join the anterior arm of the P1 fenestration. On the opposite side, the PComA coursed supero-medially to the oculomotor nerve and it had a partly duplicated posterior end, with two arms, medial, larger, and lateral, thinner, inserting successively into the left PCA.
Extremely rare anatomic variations of the circle of Willis should not be ignored when endovascular or microneurosurgical specific approaches are intended.
原始颈内动脉和基底动脉交界处的解剖变异极为罕见。我们旨在报告涉及后交通动脉（PComA）和大脑后动脉（PCA）P1 段的罕见变异。
在去除颅盖和大脑半球后，在成人尸体上解剖Willis 环。
基底动脉末端轴向向右转。右侧 PCA 的 P1 段有孔，并占据了脚间窝。右侧 PComA 越过动眼神经与 P1 孔的前臂相连。在对侧，PComA 向动眼神经的上内侧走行，其后部有部分重复，有两个分支，内侧较大，外侧较细，依次插入左侧 PCA。
当计划进行血管内或微神经外科特定方法时，不应忽视 Willis 环的极罕见解剖变异。
