Confluence of sinuses

Author: Aaron Beger, BSc • Reviewer: Roberto Grujičić, MD
Last reviewed: December 05, 2022
Reading time: 2 minutes

Confluence of Sinuses (confluens sinuum)

The confluence of sinuses (torcular of Herophilus or torcula) is a dural venous sinus that appears as a dilation at the posterior end of the superior sagittal sinus. It is located on the caudal aspect of the brain, around the internal occipital protuberance of the occipital bone.

Functionally, this vessel represents a junction between the superior sagittal, straight, occipital and the two transverse sinuses; it facilitates the blood drainage from the superior sagittal, straight and occipital sinuses to the bilateral transverse sinuses that carry the blood towards the internal jugular vein.

Key facts about the confluence of sinuses
Drains from	Superior sagittal sinus, straight sinus and occipital sinus
Drains to	Transverse sinus
Drainage area	Cerebral hemispheres

This article will discuss the anatomy and function of the confluence of sinuses.

Contents

Anatomy
Sources

+ Show all

Anatomy

Like the other dural venous sinuses, the confluence of sinuses has no valves and contains no muscle tissue in its walls. Its endothelial-lined walls are instead made up of the periosteal and meningeal layers of dura mater, which is the outermost layer of the meninges of the brain.

Typically, pressure and gravity will drive blood from the superior sagittal, straight, and occipital sinuses, into the confluence of sinuses, then laterally into the transverse sinus, destined for the internal jugular vein via the sigmoid sinus. However, since the dural venous sinuses are valveless, blood is allowed to flow in either direction.

To learn more about the dural sinuses of the brain, check out our articles, quizzes, and videos.

Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

References

Haines, D.E. (2014). Neuroanatomy in clinical context: An atlas of structures, sections, systems and syndromes (9th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
Moore, K. L., Dalley, A. F., & Agur, A. M. R. (2014). Clinically Oriented Anatomy (7th ed.). Philadelphia, PA: Lippincott Williams & Wilkins.
Netter, F. (2019). Atlas of Human Anatomy (7th ed.). Philadelphia, PA: Saunders.
Standring, S. (2016). Gray's Anatomy (41st ed.). Edinburgh: Elsevier Churchill Livingstone.
Tubbs, R. S., Shoja, M. M., Loukas, M., & Bergman, R. A. (2016). Bergman’s comprehensive encyclopedia of human anatomic variation. Hoboken: Wiley Blackwell.
Young, P.A., Young, P.H., and Tolbert, D.L. (2015). Basic Clinical Neuroscience (3rd ed.). Philadelphia, PA: Lippincott Williams & Wilkins.

Illustrators

Confluence of Sinuses (confluens sinuum) - Paul Kim

Confluence of sinuses: want to learn more about it?

Our engaging videos, interactive quizzes, in-depth articles and HD atlas are here to get you top results faster.

What do you prefer to learn with?

Videos Quizzes Both

“I would honestly say that Kenhub cut my study time in half.” – Read more.

Kim Bengochea, Regis University, Denver

Confluence of sinuses

Anatomy

Sources

Learning anatomy isn't impossible. We're here to help.

Want access to this video?

Want access to this quiz?

Want access to this gallery?

Learning anatomy isn't impossible.
We're here to help.