Brain Ventricles Location, Role, and Potential Issues

Cerebrospinal fluid (CSF) is a liquid surrounding your brain and spinal cord that cushions and protects them from trauma. It is also responsible for removing waste and delivering nutrients to your brain.

Located within your brain are four cavities where CSF is produced and stored. These are known as your brain ventricles, and they are essential to maintaining your central nervous system.

This article takes a closer look at the anatomy and functions of the brain ventricles. It also contains information about health conditions related to your ventricular system and how those conditions are diagnosed.

Anatomy of cerebrospinal fluid in brain ventricles

VectorMine / Getty Images

Anatomy

Your brain's ventricular system is comprised of four ventricles as well as small structures (foramina) that connect each ventricle.

The first and second ventricles are lateral ventricles. These c-shaped structures are located on each side of your cerebral cortex—the wrinkly outer layer of your brain. The third ventricle is a narrow, funnel-shaped structure situated between your right and left thalamus, just above your brainstem.

The fourth ventricle is a diamond-shaped structure that runs alongside your brainstem. It has four openings through which cerebrospinal fluid drains into the subarachnoid space surrounding your brain and the central canal of your spinal chord.

CSF takes the following route through the four ventricles:

  1. The walls of the lateral ventricles and the roofs of the third and fourth ventricles are lined with a layer of specialized tissues known as the choroid plexus. It's within the choroid plexus that CSF is produced.
  2. CSF passes from the lateral ventricles, through the interventricular foramen, and into the third ventricle.
  3. From the third ventricle, CSF passes through the cerebral aqueduct and into the fourth ventricle.
  4. CSF exits the fourth ventricle and drains into the subarachnoid space. CSF also passes through a structure called the obex before draining into the central canal of the spinal chord.

CSF is always being produced by the choroid plexuses of your brain ventricles. The average adult has about 150 mL of CSF circulating their ventricles and subarachnoid space at any given time.

Function

Aside from cerebrospinal fluid, your brain ventricles are hollow. Their sole function is to produce and secret cerebrospinal fluid to protect and maintain your central nervous system.

CSF is constantly bathing the brain and spinal column, clearing out toxins and waste products released by neurons. One such waste product—the amyloid A-b peptide—increases the risk of Alzheimer's disease when too much accumulates in the brain.

In addition, cerebrospinal fluid serves a number of other important functions:

  • Shock absorption: When you fall, get into a car accident, or knock your head, the CFS encasing your brain absorbs the shock so that your brain does not smack against your skull.
  • Nutrition: CSF supplies your central nervous system with essential nutrients, such as glucose, proteins, lipids, and electrolytes.
  • Intracranial pressure: A steady flow of CSF keeps the pressure around your brain stable. Too much CSF, possibly due to a traumatic brain injury or brain tumor, raises intracranial pressure.
  • Waste removal: CSF washes through your subarachnoid space, cleaning up toxins and waste products, which are then carried to your lymphatic ducts for filtration.
  • Temperature: CSF circulation keeps the temperature of your brain and spine stable.
  • Immune function: CSF contains numerous immune cells that monitor your central nervous system for foreign agents that could damage your vital organs.

Recap

Your brain has four ventricles that produce cerebrospinal fluid. CSF drains from your fourth ventricle into a canal surrounding your brain and spinal chord. This allows the fluid to protect your brain from physical trauma and bathe your central nervous system.

Associated Conditions

Infection, head trauma, or bleeding in the brain can cause inflammation in the ventricles and subarachnoid space. In turn, inflammation blocks the flow cerebrospinal fluid—causing the ventricles to swell in size and placing pressure on the brain.

The following ventricle-related conditions are life-threatening. If you are experiencing any of symptoms described below, call 911 or have someone take you to the nearest ER right away.

Hydrocephalus

Hydrocephalus is a life-threatening medical condition in which cerebrospinal fluid gets blocked and builds up in the ventricles or subarachnoid space. As a result, intracranial pressure increases and the ventricles enlarge.

Hydrocephalus can develop congenitally, meaning that it is present at birth due to a genetic or developmental abnormality. It can also develop due to a brain or spinal chord tumor, a stroke or head trauma that causes bleeding in the brain, or an infection, such as bacterial meningitis.

There are two primary types of hydrocephalus:

  • Communicating hydrocephalus: In which CFS becomes blocked in the subarachnoid space after it exits the ventricles
  • Non-communicating hydrocephalus: In which CFS becomes blocked in one or more of the structures that connect the ventricles

Any person of any age can get hydrocephalus, but it is most common in infants and adults ages 60 and older. Symptoms of hydrocephalus vary slightly among age groups.

In infants, symptoms of hydrocephalus include:

  • The infant's head rapidly gets grows in size
  • The soft spot on the top of their head bulges
  • They have trouble sucking or feeding
  • Sleepiness
  • Irritability
  • Seizures

In older adults, the symptoms include:

  • Difficulty walking, balancing or lifting their feet
  • Rapid dementia or cognitive impairments
  • Inability to hold their bladder

In all other age groups, the symptoms of hydrocephalus can also include:

  • Headache
  • Vision changes
  • Difficulty walking or talking
  • Trouble staying awake
  • Personality changes
  • Memory loss

Meningitis

The subarachnoid space is lined with membranes that are known as the meninges. Meningitis develops when this lining, along with cerebrospinal fluid, becomes infected and inflamed. Meningitis can be caused by bacterial, viral, parasitic, or fungal infections, but the most serious form is bacterial meningitis.

Bacterial meningitis can block the flow of CSF in the subarachnoid space and in the ventricles—ultimately resulting in hydrocephalus.

The symptoms of meningitis tend to come on very quickly and can include:

  • Fever and chills
  • Headache
  • Stiff neck
  • Sensitivity to light
  • Nausea or vomiting
  • Confusion
  • Seizures

Ventriculitis

The choroid plexus in your ventricles contains of layer of tissue known as the ependymal lining. Ventriculitis occurs when the ependymal lining becomes inflamed due to meningitis, head trauma, or a complication of brain surgery.

Symptoms of ventriculitis mimic meningitis and can include:

  • Fever and chills
  • Headache
  • Stiff neck
  • Confusion
  • Seizures

Brain Hemorrhage

A stroke, ruptured aneurysm, or traumatic brain injury can cause bleeding in the subarachnoid space or ventricles. These injuries are known as subarachnoid hemorrhage or intraventricular hemorrhage, respectively.

Both types of brain hemorrhage can result in hydrocephalus as blood clots form and block the flow of cerebrospinal fluid in and around the ventricles.

Symptoms of brain hemorrhage come on suddenly and can include:

  • A severe headache that peaks within seconds
  • Stiff neck
  • Blurred or double vision
  • Slurred speech
  • Weakness on one side of your body
  • Light sensitivity
  • Nausea or vomiting
  • Loss of consciousness

When to See a Doctor

If you suspect you have a brain hemorrhage, hydrocephalus, meningitis, or ventriculitis, you need to get medical attention as soon as possible. All four of these conditions are immediately life-threatening.

Tests

Hydrocephalus, meningitis, ventriculitis, and brain hemorrhage are diagnosed using one or more of the following:

Lumbar puncture (LP), also called the spinal tap, can be used to measure the pressure within in the spinal canal. It is also used to test cerebrospinal fluid for signs of infection, inflammation, or hemorrhage.

To perform a lumbar puncture, your doctor will numb your lower spine then insert a needle into your spine that measures cerebrospinal fluid pressure and collects a sample for testing. You may feel mild discomfort during the procedure, and some people have a headache afterwards.

The LP is often quite important for diagnosing central nervous system diseases. For instance, in a subarachnoid hemorrhage, ​the computed tomography (CT) scan may be normal, but the LP will reveal if there is blood in the CSF.

Summary

Cerebrospinal fluid is produced in the lining of your ventricles. After it drains from the ventricles, CFS circulates in the canals that surround your brain and spinal chord, ensuring your central nervous system is nourished and protected.

Traumatic brain injury, bacterial meningitis, and brain hemorrhage can cause inflammation in and around your ventricles. In turn, the flow of cerebrospinal fluid can get blocked and cause the ventricles to swell in size.

Medical conditions that affect the ventricles are often life-threatening; it is vital that you get treatment immediately if you suspect you are experiencing one.

A Word From Verywell

Bacterial meningitis, stroke, hydrocephalus, and other conditions that affect your ventricles can result in long-term complications, including physical disability and depression. If you or a loved one has survived one of these conditions, consider joining a support group online or in your community. Support groups are invaluable for survivors, as they offer a safe place to share your story and ask for advice from people who understand what you're going through.

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Article Sources
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