BackgroundThe cavernous sinus (CS) is a demanding surgical territory, given its deep location and the involvement of multiple neurovascular structures. Subjected to recurrent discussion on the optimal surgical access, the endoscopic transorbital approach has been recently proposed as a feasible route for selected lesions in the lateral CS. Still, for this technique to safely evolve and consolidate, a comprehensive anatomical description of involved cranial nerves, dural ligaments, and arterial relations is needed.ObjectiveDetailed anatomical description of the CS, the course of III, IV, VI, and V cranial nerves, and C3-C7 segments of the carotid artery, all described from the ventrolateral endoscopic transorbital perspective.MethodsFive embalmed human cadaveric heads (10 sides) were dissected. An endoscopic transorbital approach with lateral orbital rim removal, anterior clinoidectomy, and petrosectomy was performed. The course of the upper cranial nerves was followed from their apparent origin in the brainstem, through the middle fossa or cavernous sinus, and up to their entrance to the orbit. Neuronavigation was used to follow the course of the nerves and to measure their length of surgical exposure.ResultsThe transorbital approach allowed us to visualize the lateral wall of the CS, with cranial nerves III, IV, V1-3, and VI. Anterior clinoidectomy and opening of the frontal dura and the oculomotor triangle revealed the complete course of the III nerve, an average of 37 (±2) mm in length. Opening the trigeminal pore and cutting the tentorium permitted to follow the IV nerve from its course around the cerebral peduncle up to the orbit, an average of 54 (±4) mm. Opening the infratrochlear triangle revealed the VI nerve intracavernously and under Gruber’s ligament, and the extended petrosectomy allowed us to see its cisternal portion (27 ± 6 mm). The trigeminal root was completely visible and so were its three branches (46 ± 2, 34 ± 3, and 31 ± 1 mm, respectively).ConclusionComprehensive anatomic knowledge and extensive surgical expertise are required when addressing the CS. The transorbital corridor exposes most of the cisternal and the complete cavernous course of involved cranial nerves. This anatomical article helps understanding relations of neural, vascular, and dural structures involved in the CS approach, essential to culminating the learning process of transorbital surgery.

中文翻译：

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经眶入路海绵窦：相关颅神经的解剖学研究

背景鉴于海绵窦（CS）位置较深且涉及多个神经血管结构，因此是一个要求很高的手术区域。经过对最佳手术入路的反复讨论，最近提出内窥镜经眶入路作为治疗外侧 CS 选定病变的可行途径。尽管如此，为了使这项技术安全地发展和巩固，需要对所涉及的颅神经、硬脑膜韧带和动脉关系进行全面的解剖学描述。目的对CS、III、IV、VI和V颅神经的走行进行详细的解剖描述，颈动脉的C3-C7段，均从腹外侧内窥镜经眼眶视角进行描述。方法解剖了五个经过防腐处理的人体头部（10侧）。进行了内窥镜经眶入路，包括眶外侧缘切除、前床突切除术和岩骨切除术。上颅神经的走行是从脑干的明显起源开始，穿过中颅窝或海绵窦，一直到眼眶的入口。神经导航用于追踪神经的走向并测量其手术暴露的长度。结果经眶入路使我们能够看到 CS 的侧壁，以及颅神经 III、IV、V1-3 和 VI。前床突切除术以及额叶硬脑膜和动眼神经三角的打开显示了 III 神经的完整走行，平均长度为 37 (±2) mm。打开三叉神经孔并切割小脑幕，允许沿着 IV 神经从其围绕大脑脚的路线直至眼眶，平均 54 (±4) mm。打开滑车下三角区可显露海绵体内和格鲁伯韧带下方的 VI 神经，扩大的岩骨切除术使我们能够看到其脑池部分（27 ± 6 mm）。三叉神经根完全可见，其三个分支也完全可见（分别为 46 ± 2、34 ± 3 和 31 ± 1 毫米）。结论 解决 CS 时需要全面的解剖知识和广泛的外科专业知识。眶内走廊暴露了大部分脑池和受累脑神经的完整海绵体走行。这篇解剖文章有助于理解 CS 方法中涉及的神经、血管和硬脑膜结构的关系，这对于完成经眼眶手术的学习过程至关重要。