It has four cerebral ventricles: cavities in the brain that produce and store cerebrospinal fluid (CSF). This fluid surrounds the brain and spinal cord , softening them and protecting them from injury . It is also responsible for removing waste and delivering nutrients to your brain.
The ventricles of the brain are needed to support the central nervous system (CNS), which makes up the brain and spinal cord. The CNS is where information is processed in the body so that functions from temperature regulation to thinking, movement, and more can be controlled.
This article takes a closer look at the anatomy and function of the brain's ventricles. It also contains information about health conditions related to your ventricular system and how these conditions are diagnosed.
Your brain's ventricular system is made up of four ventricles, as well as small structures that connect each ventricle, called foramina.
The first and second ventricles are the lateral ventricles. These C-shaped structures are found on each side of the cerebral cortex , the wrinkled outer layer of the brain.
The fourth ventricle is a diamond-shaped structure that runs the length of the brain stem . It has four openings through which cerebrospinal fluid drains into the area around the brain (subarachnoid space) and the central canal of the spinal cord.
CSF travels through the four ventricles as follows:
- The walls of the lateral ventricles and the roofs of the third and fourth ventricles are lined with a layer of special tissue known as the choroid plexus . CSF is produced within the choroid plexus.
- CSF travels from the lateral ventricles through two openings called interventricular openings into the third ventricle.
- From there, the cerebrospinal fluid passes through a connective structure called the aqueduct of the brain into the fourth ventricle.
- CSF leaves the fourth ventricle and drains into the subarachnoid space. CSF also travels through a structure called the obex before draining into the central canal of the spinal cord.
The average adult has about 150 milliliters (ml) of cerebrospinal fluid circulating in the ventricles and subarachnoid space at any one time.
Your brain has four ventricles that make cerebrospinal fluid. This fluid drains from the fourth ventricle into the canal that surrounds the brain and spinal cord.
In addition to cerebrospinal fluid, the ventricles in your brain are hollow. Its sole function is to produce and secrete cerebrospinal fluid to protect and maintain your central nervous system.
Cerebrospinal fluid constantly flushes the brain and spine, cleansing the nerve cells of toxins and waste products. One of those wastes, an amyloid antibody peptide, increases the risk of Alzheimer's if too much accumulates in the brain.
In addition, cerebrospinal fluid has other important functions:
- Shock Absorption – When you fall, have a car accident, or hit your head, the CFS covering your brain absorbs shock so your brain doesn't hit your skull.
- Nutrition – Cerebrospinal fluid provides your central nervous system with essential nutrients such as glucose , protein, lipids , and electrolytes.
- Intracranial pressure : A constant flow of cerebrospinal fluid maintains a constant pressure around your brain. Too much cerebrospinal fluid, possibly due to traumatic brain injury or a brain tumor , increases intracranial pressure.
- Waste removal: CSF cleanses the subarachnoid space, removing toxins and waste products, which are then transported to the lymphatic ducts for filtration.
- Temperature: Circulation of cerebrospinal fluid maintains a stable temperature in the brain and spine.
- Immune function : Cerebrospinal fluid contains many immune cells that check your central nervous system for foreign agents that can damage your vital organs.
Infection, head trauma, and bleeding in the brain can cause inflammation of the ventricles and subarachnoid space. This inflammation blocks the flow of cerebrospinal fluid, causing the ventricles to enlarge and put pressure on the brain.
The following ventricular conditions are life threatening. If you experience any of the symptoms below, call 911 or have someone else drive you to the nearest emergency room right away.
Hydrocephalus is a life-threatening disorder in which cerebrospinal fluid becomes blocked and accumulates in the ventricles or subarachnoid space. As a result, the pressure inside the skull increases and the ventricles increase.
Hydrocephalus may be present at birth due to genetic or developmental abnormalities. It can also develop from a brain or spinal cord tumor, stroke, or head injury that causes bleeding in the brain, or an infection such as bacterial meningitis .
There are two main types of hydrocephalus:
- Communicating hydrocephalus: in which the CFS is blocked in the subarachnoid space after exiting the ventricles.
- Non-communicating hydrocephalus: in which the CFS is blocked in one or more structures that connect the ventricles.
Anyone of any age can get hydrocephalus, but it is most common in babies and adults over the age of 60. The symptoms of hydrocephalus vary slightly depending on the age group.
In babies, symptoms of hydrocephalus include:
- The baby's head is rapidly growing in size.
- The soft spot on the top of the head sticks out
- They have problems sucking or feeding.
In older adults, symptoms include:
- Difficulty walking, balancing, or lifting your feet;
- Rapid dementia or cognitive decline
- Inability to support the bladder.
In all other age groups, symptoms of hydrocephalus can include:
- Vision changes
- Difficulty walking or speaking
- Waking problems
- Personality changes
- Memory loss
The subarachnoid space is lined with membranes known as the meninges. Meningitis develops when this mucous membrane, along with the cerebrospinal fluid, becomes infected and inflamed.
Bacterial meningitis can block the flow of cerebrospinal fluid into the subarachnoid space and ventricles, eventually leading to hydrocephalus.
Symptoms of meningitis appear very quickly and can include:
- Fever and chills
- Stiff neck muscles
- Sensitivity to light
- Nausea or vomiting
The choroid plexus of the ventricles is made up of a layer of tissue known as the ependymal lining. Ventriculitis occurs when this lining becomes inflamed due to meningitis, a head injury, or a complication of brain surgery .
Symptoms of ventriculitis resemble meningitis and may include:
- Fever and chills
- Stiff neck muscles
A stroke, ruptured aneurysm, or traumatic brain injury can cause bleeding into the subarachnoid space or ventricles. These injuries are known as subarachnoid hemorrhage or intraventricular hemorrhage, respectively.
Both types of brain hemorrhage can lead to hydrocephalus, as blood clots form that block the flow of cerebrospinal fluid to and around the ventricles of the brain.
Symptoms of a brain hemorrhage happen suddenly and can include:
- Severe headache that peaks in a few seconds.
- Stiff neck muscles
- Blurred or double vision
- Speak slurred
- Weakness on one side of the body
- Nausea or vomiting
- Loss of consciousness
If you suspect you have a brain hemorrhage, hydrocephalus, meningitis, or ventriculitis, all affecting the ventricles, you should seek medical attention as soon as possible. These conditions are immediately life-threatening.
Hydrocephalus, meningitis, ventriculitis, and brain hemorrhage are diagnosed by one or more of the following:
A lumbar puncture (LP), also called a lumbar puncture, can be used to measure pressure in the spinal canal. It is also used to check the cerebrospinal fluid for signs of infection, inflammation, or bleeding.
To perform a lumbar puncture, your doctor will numb the lower part of your spine. A needle is then inserted into the numb area to measure the pressure of the cerebrospinal fluid and take a sample for analysis.
Lumbar puncture is often very important in diagnosing diseases of the central nervous system. For example, for subarachnoid hemorrhage, CT may be normal, but a lumbar puncture will show if there is blood in the cerebrospinal fluid.
Imaging tests and lumbar puncture are used to diagnose trauma and disease of the ventricles of the brain. A lumbar puncture will show if there is blood in the spinal cord, which may indicate a brain hemorrhage. You can also look for signs of infection.
Cerebrospinal fluid is produced by the mucous membrane of the ventricles of the brain. After draining from these four chambers, CFS circulates through the channels that surround your brain and spinal cord, providing nutrition and protection to your central nervous system.
Traumatic brain injury, bacterial meningitis, and brain hemorrhage can cause inflammation in and around the ventricles. As a result, the flow of cerebrospinal fluid can become blocked and cause enlargement of the ventricles.
Diseases that affect the ventricles are often life-threatening. If you notice any accompanying symptoms, it is imperative to begin treatment immediately.
Get the word of drug information
If you or your loved one has experienced one of these conditions, consider joining an online or community support group. Support groups can be invaluable to many survivors, providing a safe place to share personal stories and seek advice from people who understand what you are going through.