Redefining the Limits of the Central Skull Base: An Anatomical Perspective

Introduction: The skull base is a complex anatomical region composed of bones and soft tissues containing important neurovascular structures. A thorough understanding of its anatomy and pathology is essential for diagnosing and managing various conditions affecting this area. Based on the intracranial view from above, the skull base has been conventionally divided into anterior, central, and posterior components. Traditionally, the central skull base (CSB) has been delimited by an arbitrary line along the anterior margin of the sella, with broad lateral boundaries to the squamous temporal bones, and posteriorly limited by the clivus. Various authors have attempted to define these limits, often relying on radiological descriptions, resulting in a lack of consensus on the exact anatomical demarcations of this region. In this study, we aimed to provide a detailed anatomical characterization of the CSB based on anatomical cadaveric dissections and a comprehensive literature review.

Materials and Methods: Five postmortem embalmed heads with latex injection have been dissected through a microsurgical and endoscopic route to review the limit of the CSB. For this review, we also searched PubMed databases for studies discussing the anatomy and limits of CSB. After reviewing the search results, a total of seven articles were selected.

Results: The CSB represents a complex intersection between the intracranial compartment, paranasal sinuses, and suprahyoid neck. The limits of the CSB are defined, laterally by the boundaries set by the carotid arteries, petrotentorial edge, and cranial nerves; anteriorly are delineated by the limbus sphenoidale, orbital plates, and cribriform region; and posteriorly the jugular foramen and cranio-cervical junction. Borges et al described the CSB's anterior limit as following the chiasmatic sulcus and other structures but later revised this to the tuberculum sella. Wu et al and Philips et al provided radiological descriptions with differing boundaries. Gohlke et al proposed a modernized, three-dimensional spherical model, including key structures such as the optic chiasm, pterygopalatine fossa, and cavernous sinus.

Conclusion: Pathologies affecting the CSB may arise from the intrinsic bony-cartilaginous structures of the skull base, arise from the intracranial component, and invade the skull base from above, or invade the skull base from adjacent exocranial compartments. Endoscopic endonasal surgery is the preferred method for addressing these lesions due to its minimally invasive nature, though not all CSB lesions are accessible through this approach. Our study aims to provide a detailed anatomical characterization of the CSB from a neurosurgeon's perspective, assessing the accessibility and resectability of lesions via endonasal endoscopy. By defining the CSB as a three-dimensional entity, we seek to delineate the limitations of the endonasal approach and enhance surgical planning and outcomes for CSB pathologies.

 

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No conflict of interest has been declared by the author(s).

Publication History

Article published online:
07 February 2025