Confluence of Sinuses, Posterior View

Description

Posteriorly, the dural venous confluence (torcular Herophili) sits at the internal occipital protuberance, where the superior sagittal sinus descends in the midline and meets the straight sinus arriving from the tentorial attachment. From this junction, the paired transverse sinuses run inferolaterally along the posterolateral margins of the tentorium cerebelli toward the sigmoid sinuses. Adjacent surface anatomy of the occipital lobes and the superior cerebellum frames the venous crossroads, with the cerebellar hemispheres positioned inferior to the occipital poles and the upper cervical spinal cord continuing caudally through the foramen magnum. Peripheral nerves branching from the spinal cord are rendered as longitudinal roots and segmental exits, contrasting with the deep blue dural channels interlaced among red arterial elements. This posterior perspective matters because it clarifies venous drainage patterns that dictate both the spread of intracranial thrombosis and the safety margins of midline posterior fossa and occipital approaches. Injury to the transverse sinus during suboccipital craniectomy, or occlusion in dural venous sinus thrombosis, can redirect flow through asymmetric channels and raise intracranial pressure, with papilledema and headache as common clinical consequences. A practical landmark. The relationship between the straight sinus, tentorium cerebelli, and confluence is also central to interpreting MR venography variants, including a dominant unilateral transverse sinus or a persistent occipital sinus. Use this illustration for neuroanatomy and neuroradiology teaching when introducing the dural venous sinuses, for operative atlases discussing midline suboccipital exposure, and for publications on venous sinus thrombosis, posterior fossa tumors, or dural arteriovenous fistulas near the torcular region. Anatomical accuracy verified by SciePro's Medical Advisory Board.