Intracranial Venous System

Venous sinuses: locations on axial cuts (MRI of the brain after medium contrast administration)

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Venous sinuses: locations on sagittal and coronal slices (MRI of the brain after medium contrast administration)

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Venous sinuses of the brain: sequence Time-of-flight

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Intracranial Venous System

The intracranial or cerebral venous system is a network of nerves made up of two systems working together: the superficial system and the deep system⁽¹⁾.

The superficial cerebral system has sagittal sinuses and cortical veins. The sinuses and the veins both drain deoxygenated blood from the surfaces of the brain’s hemispheres⁽²⁾. 

Meanwhile, the deep cerebral system is made up of the lateral, straight, and sigmoid sinuses. The sinuses drain deoxygenated blood from the deeper areas of the cerebral hemispheres⁽³⁾.

The superficial and the deep venous systems work together to drain the blood with carbon dioxide and metabolic residues away from the brain. Draining this type of blood allows oxygenated blood to take its place⁽⁴⁾.

The intracranial venous system drains the eyes, brain, meninges (coverings of the spinal cord and the brain), and certain blood vessels on the face⁽⁵⁾.

The superficial intracranial venous system begins its work through subcortical veins, which drain the outer area of the largest part of the brain called the cerebral cortex⁽⁶⁾.

After the cortex’s surface is drained, deoxygenated blood flows to the veins sitting on the cortex’s surface. The veins then drain into the cerebral veins found on the brain’s surface⁽⁷⁾.

The three most extensive cerebral veins in the human body are⁽⁸⁾: 

• The superficial middle cerebral veins
• The vein of Trolard (the vein connecting the superior sagittal sinus to the middle cerebral vein)
• The vein of Labbe (the vein connecting the middle cerebral vein to the lateral sinus)

Meanwhile, the deep cerebral veins work with the basal veins to drain deoxygenated blood from the cerebral hemisphere and the basal ganglia (a group of structures in the brain linked to the thalamus)⁽⁹⁾.

Intracranial Venous System Diseases

The intracranial venous system has no muscular layer or valves, making it vulnerable to ruptures and subdural hematomas (internal bleeding)⁽¹⁰⁾.

Below are some of the medical conditions concerning the cerebral venous system:

Stroke

Stroke refers to the abrupt interruption of blood flow to the brain, causing loss of neurological function⁽¹¹⁾. 

Stroke may be triggered by a blockage, leading to an ischemic stroke, or by bleeding in the brain, resulting in a hemorrhagic stroke⁽¹²⁾. 

Symptoms of stroke include⁽¹³⁾: 

• Nausea or vomiting
• Confusion
• Memory loss
• Slurred speech
• Severe headache
• Numbness in one side of the arm, leg, or the face
• Vision loss or reduced vision
• Loss of balance or coordination

According to the American Association of Neurological Surgeons (AANS), stroke may occur at any age. However, the condition is more common in older adults⁽¹⁴⁾.

Stroke prevention may help reduce death caused by the disease. Below are some of the treatable risk factors for stroke⁽¹⁵⁾:

• Artery disease
• Smoking
• High blood pressure
• High blood cholesterol
• Diabetes
• Obesity

Cerebral Venous Sinus Thrombosis (CVST)

Cerebral venous sinus thrombosis (CVST) is a stroke involving blood clot formation in the cerebral venous sinuses. A blood clot prevents deoxygenated blood from draining out of the brain⁽¹⁶⁾. 

A blood clot in the brain may result in blood cells breaking and leaking into the brain tissues, creating a hemorrhage⁽¹⁷⁾.

Symptoms of the medical condition include⁽¹⁸⁾:

• Blurred vision
• Headache
• Seizures
• Fainting
• Poor control of body movement
• Coma

A doctor may recommend the following tests to diagnose CVST⁽¹⁹⁾:

• Blood tests
• Magnetic resonance imaging (MRI) scan
• Venography (X-ray of the veins)
• Computed tomography (CT) scan
• Angiography (X-ray of blood vessels)
• Ultrasound

To treat the medical condition, a physician may recommend the following⁽²⁰⁾:

• Antibiotics
• Anti-seizure medicines
• Monitoring the pressure in the brain
• Anticoagulants or anti-clotting medicines
• Surgery

Cerebral Aneurysms

A cranial or cerebral aneurysm occurs when an area in the brain with blood vessels weakens, inflating a vessel wall. Aneurysms typically develop where a blood vessel branches because the points where the blood vessels meet are structurally more vulnerable⁽²¹⁾.

The condition may result from a congenital disability or other medical conditions, such as high blood pressure, atherosclerosis (fat buildup in the arteries), or head trauma⁽²²⁾.

Patients with a cerebral aneurysm may experience the following symptoms⁽²³⁾:

• Headache
• Vomiting and nausea
• Double vision
• Stiff neck
• Light sensitivity
• Numbness or loss of sensation 

When the inflamed vessel wall ruptures, it usually causes bleeding in the brain, resulting in a subarachnoid hemorrhage. Blood may also leak into other areas surrounding the brain, causing an intracranial hematoma (blood clot)⁽²⁴⁾. 

The blood from a ruptured brain aneurysm may irritate, damage, or destroy brain cells. The destruction of brain cells may cause problems with certain body functions or mental skills⁽²⁵⁾.

The bleeding in the brain may also result in brain damage, paralysis, or coma. According to the AANS, ruptured brain aneurysms are fatal in approximately 50% of cases⁽²⁶⁾.

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1. Safadi, A. & Tadi, P. (2020). Anatomy, Head and Neck, Cerebral Venous System. StatPearls. https://www.ncbi.nlm.nih.gov/books/NBK560496/
2. Ibid
3. Ibid
4. Ibid
5. Ibid
6. Ibid
7. Ibid
8. Ibid
9. Ibid
10. Ibid
11. American Association of Neurological Surgeons. Cerebrovascular Disease. Retrieved from https://www.aans.org/en/Patients/Neurosurgical-Conditions-and-Treatments/Cerebrovascular-Disease
12. Ibid
13. Ibid
14. Ibid
15. Ibid
16. Johns Hopkins Medicine, based in Baltimore, Maryland. Cerebral Venous Sinus Thrombosis (CVST). Retrieved from https://www.hopkinsmedicine.org/health/conditions-and-diseases/cerebral-venous-sinus-thrombosis
17. Ibid
18. Ibid
19. Ibid
20. Ibid
21. American Association of Neurological Surgeons. Op cit.
22. Ibid
23. Ibid
24. Ibid
25. Ibid
26. Ibid

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