What Is a Cerebral Herniation?

Medically Reviewed by Christopher Melinosky, MD on October 23, 2023
Written by WebMD Editorial Contributors
3 min read

A cerebral herniation or brain herniation is a serious medical condition that happens when brain tissues move from one part of the brain to another adjacent part of the brain. It is usually caused when another condition causes swelling or pressure inside the brain. Cerebral herniations are severe and need immediate treatment. 

A significant and sudden cerebral event usually causes cerebral herniation. Some of these events include: 

  • Brain swelling. Brain swelling is often caused by infections like encephalitis, measles, mumps, polio, meningitis, or rabies. However, with the advent of vaccines and modern medical care, brain swelling is not very common.
  • Injury to the head. Blunt trauma to the head resulting in bleeding, concussions, skull fractures, or hematomas can easily lead to a cerebral herniation.
  • Strokes. Both ischemic strokes (caused by blocked arteries) and hemorrhagic strokes (caused by excess bleeding) can lead to cerebral herniations. Strokes cause stress and damage to brain cells, leading to cerebral herniation.
  • Brain Tumor. Metastatic brain tumors (that come from another part of the body) or primary brain tumors (that grow in the brain) both cause enough expansion to create cerebral herniation.
  • Abscess. An abscess can collect fluid n the brain, usually through some sort of infection. This buildup of fluid is what creates the pressure that might move tissue and cause a herniation. 
  • Radiation therapy. Radiation treatments often make the brain swell. This is usually a short-term swelling, but you should pay attention if you begin to experience severe headaches, sickness, or seizures after your radiation treatment. 

The five types of herniations depend on how and where the brain tissue is moved. These five types of cerebral herniations are:‌

Subfalcine herniation. These take place in a part of the brain called the cingulate gyrus. The cingulate gyrus is a part of the brain just behind the frontal lobe. During this herniation, the cingulate gyrus is pushed into another part of the brain that is much deeper and in the skull. 

Transtentorial herniation. These occur when the temporal lobe is squeezed under the tentorium. The tentorium is a part of the brain located towards the neck.‌

Central herniation. These occur in the temporal lobe. The temporal lobe is located in the middle of the brain, above the beginning of your spinal cord. During a central herniation, the temporal lobe gets pushed down to the tentorial notch, which is the closest part of the brain to the spine. 

Tonsillar herniation. These occur in the infratentorial area of the brain. The herniation pushes back brain tissue into the area that connects the skull to the spine.

Upward transtentorial herniation. This can happen when something like a mass or blood hemorrhage occurs at the brain stem, affecting the blood flow.

Some of the signs you may have a cerebral herniation are:

  • Strange or unusual pulse
  • High blood pressure
  • Headaches
  • Feeling weak
  • Cardiac arrest
  • Loss of consciousness
  • Inability to blink, gag, or react to light 
  • Not being able to breathe 
  • Dilated pupils‌

Call 911 if you suspect cerebral herniation in someone. In order to check if you have a cerebral herniation and to find it in your brain, your doctor will likely perform one or more of the following tests:

  • CT scan
  • MRI

A cerebral herniation is a very serious brain condition. If untreated, it can lead to severe brain damage or even death.‌

Depending on the part of your brain that's affected, your body can start to shut down, and you can lose basic functioning like breathing or blood circulation. Death is very possible for people who experience cerebral herniations. ‌

In the event that you have a cerebral herniation, your healthcare team will attempt to decrease the brain swelling however they can. 

Depending on the causes of the herniation, some of the treatments include:

  • Draining out any excess fluids in the brain
  • Taking medication to reduce swelling
  • Taking medication specifically for brain swelling
  • Upping the rate of breath by installing a tube in the airway
  • Breaking up blood and blood clots 
  • Taking away parts of the skull to decrease internal pressure

Cerebral herniations are usually a result of untreated illnesses or severe head injuries. It's hard to prevent these situations as they're often accidental. Make sure you go to the doctor frequently if you have a severe condition like a tumor, or have suffered significant head trauma in the past.