Superior Perspective of the Occipital Sinus

Description

Viewed from a superior aspect with the calvaria removed and the dura mater reflected, the dural venous sinuses are exposed as blue channels within the cranial cavity. The superior sagittal sinus runs in the midline along the attached margin of the falx cerebri and drains posteriorly to the confluence of sinuses at the internal occipital protuberance. From the confluence, the transverse sinuses course laterally along the tentorium cerebelli to become the sigmoid sinuses, which curve inferomedially toward the jugular foramen, while the occipital sinus descends in the posterior cranial fossa along the falx cerebelli toward the internal vertebral venous plexus near the foramen magnum. Small but memorable. That occipital sinus matters because it is the most variable of the dural sinuses, yet it can become a dominant outflow pathway when the transverse or sigmoid sinuses are hypoplastic or thrombosed, a pattern you want in mind when reviewing MRV/CTV and when planning posterior fossa exposure. Midline posterior approaches, including suboccipital craniotomy and foramen magnum decompression, risk brisk bleeding if the occipital sinus or marginal sinus ring is well developed and tethered to the dura at the craniocervical junction. Connections to the confluence and to the internal vertebral venous plexus also help explain collateral venous drainage and the spread of infection or dural arteriovenous fistulas around the occiput. Neuroanatomy and neurosurgery teaching sessions use this view to orient learners to the confluence of sinuses, tentorial attachments, and the expected drainage routes from the superior sagittal sinus into the transverse and sigmoid pathways. It also fits cleanly into radiology atlases and operative planning materials that correlate superior views of the dural venous system with venography, posterior fossa tumor approaches, and venous sinus thrombosis cases. Anatomical accuracy verified by SciePro's Medical Advisory Board.