The Connective Tissue Architecture of the Cavernous Sinus: An Anatomical Study and Unifying Conceptualization

• Published in: World neurosurgery 2024-12, p.123573, Article 123573
• Main Authors: Pichugin, Arseniy, Formentin, Cleiton, Chan, Yun-Kai, Trondin, Albert, Wang, Eric W., Snyderman, Carl H., Gardner, Paul A., Zenonos, Georgios A.
• Format: Article
• Language: English
• Subjects: cavernous sinus; cavernous sinus anatomy; cavernous sinus walls; dural layers; neuroanatomy; skull base anatomy
• ISSN: 1878-8750; 1878-8769; 1878-8769
• DOI: 10.1016/j.wneu.2024.123573

The aim of this study was to synthesize existing knowledge regarding the anatomy of the cavernous sinus (CS), critically evaluate the current anatomical hypotheses concerning its walls, to conduct anatomical dissections and develop a comprehensive understanding of the connective tissue structure of the CS. We performed systematic dissections on fifteen fresh adult cadavers. Specifically, five specimens were approached laterally, five were sectioned in the axial plane, and five were dissected using endoscopic endonasal techniques. Based on histological and embryological data, we formulated several anatomical concepts and examined them through dissection studies. 1) An uninterrupted periosteum envelops all surfaces of the skull and establishes a periosteal dural layer within the cranial cavity. 2) All structures of the neuraxis are encased by a meningeal layer of dura mater. 3) Cranial nerves (CN) are ensheathed by one layer of meningeal layer as they pierce it. This meningeal layer invaginates along the course of the nerves to various lengths forming the corresponding CN cisterns before fusing with the nerve’s perineurium. 4) Fibers of the periosteal layer that are strained between the nearby bony structures form a thin periosteal “ligamentous” layer. This layer is mostly attenuated but becomes more robust in named “ligaments”. These ligaments covered by meningeal layer of dura form “dural folds” such as anterior and posterior petroclinoidal folds. Consequently, the lateral wall of the CS is composed of the following elements: 1) the meningeal layer associated with the mesial temporal lobe, 2) a thin periosteal "ligamentous" layer, and 3) the meningeal layers corresponding to cranial nerves III, IV, and V1 originating from the posterior cranial fossa (PCF). The medial wall of the CS is constituted by a single layer of periosteal dura inferiorly and a meningeal layer superiorly. The superior wall of the CS is exclusively formed by the periosteal layer of the anterior clinoid process at the anterior aspect of the clinoidal triangle (referred to as the carotidooculomotor membrane). In contrast, the posterior aspect of the oculomotor triangle consists of both a meningeal layer and a thin "periosteal ligamentous layer" that extends between three more substantial periosteal condensations: the anterior and posterior petroclinoidal ligaments and the interclinoidal ligament. The posterior wall of the CS is comprised of the meningeal layer of the dura mater from the