Confluence of Sinuses

Description

Posterior to the cerebral hemispheres, the superior sagittal sinus descends in the midline within the falx cerebri and meets the straight sinus, which runs along the junction of falx cerebri and tentorium cerebelli, at the confluence of sinuses (confluens sinuum) near the internal occipital protuberance. The occipital sinus approaches from inferior and posterior along the attached margin of the falx cerebelli, joining the same venous crossroads before outflow continues into the transverse sinuses bilaterally. Adjacent deep drainage, including the great cerebral vein (of Galen) feeding the straight sinus, is typically implied by the course of the straight sinus even when not fully isolated. Midline venous anatomy is the focus. This confluence matters because it is where intracranial venous drainage can bottleneck or reroute during dural venous sinus thrombosis, and because anatomic dominance (often one transverse sinus larger) influences the pattern of venous hypertension and collateralization. For posterior fossa and occipital craniotomies, the torcular region is a no-go zone for aggressive dural stripping; inadvertent laceration can cause rapid blood loss and air embolism, and it complicates exposure when the occipital sinus is prominent. This view also helps clarify why elevated intracranial pressure can transmit backward along the superior sagittal sinus and impair arachnoid granulation resorption. Use this asset in neuroanatomy teaching on dural venous sinuses, in neurosurgical atlases covering occipital approaches and tentorial anatomy, or in radiology education to correlate MRV/CTV appearances of the torcular Herophili and transverse sinus asymmetry. Anatomical accuracy verified by SciePro's Medical Advisory Board.