Cut Section of the Skull Containing the Inferior Petrosal Sinus

Description

Sectioned calvaria and posterior cranial fossa expose the dural venous sinuses on the endocranial surface, with the inferior petrosal sinus coursing anteromedially in the petro-occipital fissure between the petrous part of the temporal bone and the basilar part of the occipital bone. Superiorly, the superior sagittal sinus tracks along the midline groove toward the confluence of sinuses, then drains laterally into the transverse sinus and posteriorly into the sigmoid sinus. Bony landmarks around the jugular foramen sit inferolateral to the clival region, aligning the inferior petrosal sinus with its terminal drainage into the internal jugular vein. That petroclival corridor matters in real procedures. The inferior petrosal sinus is the standard venous route for bilateral inferior petrosal sinus sampling in suspected ACTH-dependent Cushing disease, and this cut section clarifies why catheterization targets the jugular bulb region and why asymmetric drainage or hypoplastic channels can complicate interpretation. It also orients the sinus to adjacent cranial base anatomy relevant to petroclival meningiomas and to dural arteriovenous fistulas that may recruit the inferior petrosal sinus and produce cranial neuropathies through venous hypertension near the cavernous sinus and petrous apex. Small channel. High stakes. Use this plate in neuroanatomy and head and neck anatomy teaching to anchor dural venous sinus pathways to cranial sutures and fossae, and in endocrine or neurosurgical publishing when explaining inferior petrosal sinus sampling technique, jugular foramen relationships, or posterior fossa venous drainage patterns. Anatomical accuracy verified by SciePro's Medical Advisory Board.