Confluence of Sinuses Viewed in a Section of the Skull

Description

Arising in the midline at the internal occipital protuberance, the confluence of sinuses (confluens sinuum, torcular Herophili) appears as the posterior meeting point of the superior sagittal sinus, straight sinus, and occipital sinus within the attached meningeal layer of dura mater. The superior sagittal sinus courses posteriorly along the superior margin of the falx cerebri, while the straight sinus tracks posteroinferiorly at the junction of falx cerebri and tentorium cerebelli to reach the torcula. From this crossroads, paired transverse sinuses extend laterally along the attached margin of the tentorium cerebelli, hugging the inner table of the occipital bone and posterior cranial fossa. A key landmark. Clinical context often turns on this exact geometry because the torcular region is where deep and superficial cerebral venous drainage converges before exiting toward the sigmoid sinus and internal jugular vein. Thrombosis of the superior sagittal sinus or straight sinus can propagate into the confluence, producing raised intracranial pressure, papilledema, venous infarction, or hemorrhage, and the pattern of involvement helps you anticipate whether cortical veins, deep venous structures, or both are compromised. The posterior midline location also matters in occipital fractures and posterior fossa approaches, where unintended dural sinus injury can cause brisk venous bleeding and air embolism. Use this sectional skull view to teach dural venous sinus anatomy in neuroanatomy and head and neck courses, to clarify torcula terminology (torcular, trocular, Herophili) in textbooks, or to support neurosurgical and neuroradiology materials on cerebral venous sinus thrombosis and posterior cranial fossa trauma. Anatomical accuracy verified by SciePro's Medical Advisory Board.