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Basics Upper limb Lower limb Spine and back Thorax Abdomen Pelvis and perineum Head and neck Neuroanatomy Cross sections Radiological anatomy
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ArticlesAnatomyNeuroanatomyMeninges, ventricular system and subarachnoid space Sigmoid sinus
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ArticlesAnatomyNeuroanatomyMeninges, ventricular system and subarachnoid space Sigmoid sinus

Sigmoid sinus

Author: Roberto Grujičić, MD • Reviewer: Jana Vasković, MD
Last reviewed: November 03, 2023
Reading time: 5 minutes

Sigmoid sinus (Sinus sigmoideus)

The sigmoid sinus is a paired intracranial venous channel. It arises from the transverse sinus at the level where the transverse sinus leaves the tentorium cerebelli. The sigmoid sinus courses along the floor of the posterior cranial fossa to enter the jugular foramen. It drains into the jugular bulb via which it connects with the internal jugular vein.

Throughout its course, the sigmoid sinus receives tributaries that connect it to the pericranial veins. These tributaries include the mastoid and (posterior) condylar emissary veins. Additionally, the sigmoid sinus receives tributaries that drain the blood from the medulla oblongata, pons and cerebellum.

This article will discuss the anatomy and function of the sigmoid sinus.

Key facts about the sigmoid sinus
Drains from Transverse sinus
Tributaries Mastoid emissary veins, condylar emissary veins, inferior cerebellar veins
Drains to Internal jugular vein
Drainage area Transverse sinus, cerebellum, pons, medulla oblongata
Contents
  1. Origin and course
  2. Function
  3. Clinical notes
    1. Sigmoid sinus diverticulum
  4. Sources
+ Show all

Origin and course

Sigmoid sinus
Sinus sigmoideus
1/5
Synonyms: Sinus sigmoides

The sigmoid sinus is a paired intracranial vessel. It begins as a continuation of the transverse sinus around the opening on the tentorium cerebelli. From here, it descends downward, forming an S-shaped curve in a groove on the mastoid process of temporal bone. This groove is called the groove for sigmoid sinus. It then courses over the jugular process of the occipital bone to emerge posterior to the jugular foramen. When it reaches the foramen, the sigmoid sinus is situated at the posterolateral part of the foramen with a meningeal branch of the occipital artery.

The sigmoid sinus terminates by an expansion known as the jugular bulb. This bulb is a junction between the sigmoid sinus and the internal jugular vein. Along its course, the sigmoid sinus receives a number of tributaries. Keep in mind that the venous system of the brain is largely variable and the tributaries of the sigmoid sinus are no exception. Some of the most common tributaries include the following vessels:

  • Mastoid emissary veins in the mastoid foramen that connect the sigmoid sinus with the posterior auricular or occipital veins.
  • Condylar emissary vein that runs between the sigmoid sinus and veins in the suboccipital triangle through the (posterior) condylar canal.
  • Venous plexus of the hypoglossal canal, which is sometimes only a single vein that runs between the sigmoid sinus and the internal jugular vein.
  • Inferior cerebellar veins, that drain the inferior portion of the cerebellum.
  • Small unnamed tributaries from the pons and medulla.

Function

The main function of the sigmoid sinus is to conduct blood from the transverse sinus to the internal jugular vein. Along the way, the sigmoid sinus receives tributaries that collect blood from the pericranial veins, and in some cases from pons, medulla oblongata and cerebellum.

The course of the sigmoid sinus is very variable and of major clinical importance since the neurosurgical approaches to the posterior fossa of the skull are classified according to the position of the sinus; retrosigmoid surgeries are performed behind the sinus, while the presigmoid are performed in front of it.

Explore the anatomy of the dural venous sinuses using the videos, articles, labeled illustrations and quizzes in the following study unit:

Dural venous sinuses Explore study unit

Clinical notes

Sigmoid sinus diverticulum

The sigmoid sinus diverticulum is a rare vascular anomaly. It is an outpouching (diverticulum) of the wall of the sigmoid sinus. The diverticulum often has a tendency to grow and protrude into the mastoid process. The most common symptom of this condition is pulsatile tinnitus (noise or ringing) in the ear on the side of the anomaly.

The diagnosis is most commonly established by cerebral angiography. The treatment can be achieved with surgical procedures, usually via the endovascular coiling.

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:

  • 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). Bergmans comprehensive encyclopedia of human anatomic variation. Hoboken: Wiley Blackwell.
  • Van Osch, K., Allen, D., Gare, B., Hudson, T. J., Ladak, H., & Agrawal, S. K. (2019). Morphological analysis of sigmoid sinus anatomy: clinical applications to neurotological surgery. Journal of otolaryngology - head & neck surgery = Le Journal d'oto-rhino-laryngologie et de chirurgie cervico-faciale, 48(1), 2.
  • Aly I., Tubbs, S.R. (2020). Anatomy, Imaging and Surgery of the Intracranial Dural Venous Sinuses. Chapter 5 - The Sigmoid Sinus. Elsevier. pp 47-58.

Illustrators:

  • Sigmoid sinus (superior view) - Paul Kim
  • Groove for sigmoid sinus (superior view) - Yousun Koh
  • Sigmoid sinus (superior view) - Paul Kim

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