Salas E, Ziyal I M, Sekhar L N, Wright D C
Department of Neurological Surgery, The George Washington University Medical Center, Washington, District of Columbia 20037, USA.
Neurosurgery. 1998 Sep;43(3):557-61; discussion 561-2. doi: 10.1097/00006123-199809000-00082.
The most frequent embryonic communication between the vertebrobasilar and carotid systems is a persistent trigeminal artery (PTA). It has been observed in 0.1 to 0.2% of cerebral angiograms. We found this variation in an anatomic specimen, and after microscopic dissection, we performed an analysis of the course of the PTA and its relationship with the abducens nerve and the meningohypophyseal trunk.
A PTA was incidentally encountered in an injected cadaver specimen during a transpetrosal approach. This embryonic variation and its anatomic relationship are discussed.
The PTA can take either a lateral or medial course regarding its relationship with the abducens nerve. When the PTA originates from the posterolateral aspect of the posterior bend of the cavernous carotid artery (C4 segment), it crosses underneath and distorts the abducens nerve, continuing between the abducens and trigeminal nerves. When taking a medial course, the PTA arises from the posteromedial aspect of the posterior bend of the cavernous carotid at the same segment and pierces the clival dura at the dorsum sellae. Cranial nerve displacement or distortion is less likely in this variation. In an analysis of carefully described anatomic studies, the PTA and meningohypophyseal trunk were found arising from either common or separated origins.
The most frequent embryological anastomosis between the carotid and vertebrobasilar system is the PTA. Its course and relationship with the cranial nerves may determine its clinical presentation.
椎基底动脉系统与颈动脉系统之间最常见的胚胎期交通是持续存在的三叉动脉（PTA）。在0.1%至0.2%的脑血管造影中可观察到这种情况。我们在一个解剖标本中发现了这种变异，经过显微镜下解剖后，我们对PTA的走行及其与展神经和脑膜垂体干的关系进行了分析。
在经岩骨入路过程中，在一个注入标本的尸体上偶然发现了一条PTA。讨论了这种胚胎期变异及其解剖关系。
就其与展神经的关系而言，PTA可走行于外侧或内侧。当PTA起源于海绵窦段颈动脉（C4段）后弯的后外侧时，它在展神经下方穿过并使其变形，继续走行于展神经和三叉神经之间。当走行于内侧时，PTA起源于同一节段海绵窦段颈动脉后弯的后内侧，穿破鞍背处的斜坡硬脑膜。这种变异中脑神经移位或变形的可能性较小。在对详细描述的解剖学研究进行分析时，发现PTA和脑膜垂体干起源于共同或分开的起始点。
颈动脉系统与椎基底动脉系统之间最常见的胚胎期吻合是PTA。其走行及其与脑神经的关系可能决定其临床表现。
