Midline Shift After Head Trauma

The brain is naturally balanced between the left and the right hemispheres. On a computed tomography (CT) scan that looks down at the brain from the top of the head, there is a groove that runs between both sides of the brain that is midline to the body. The spinal cord emerges at the middle-base of the brain and continues down the center of the back.

A midline shift occurs when something pushes this natural centerline of the brain to the right or to the left. It is a concerning sign after head trauma.

Woman having a CT scan
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Midline Shift and Intracranial Pressure

The brain maintains a natural pressure level at all times. Normal pressure within the skull is 7-15 mm/Hg. This baseline pressure is created by fluid, tissue and blood flow within the bony skull.

Head trauma can immediately and significantly increase intracranial pressure (ICP). If there is a powerful blow to the head, blood vessels rupture and bleed into and around the brain. Since the heart continues to pump fresh blood into the brain, the extra blood that is leaking out of broken blood vessels begins to accumulate. This raises overall brain pressure and the growing collection of blood, called a hematoma, begins to push against brain tissue.

Other causes of increased ICP after head trauma include brain swelling around the site of injury, a condition called hydrocephalus which is a collection of fluid in the ventricles of the brain, and infection.

A midline shift occurs when the pressure exerted by the buildup of blood and swelling around the damaged brain tissues is powerful enough to push the entire brain off-center. This is considered a medical emergency and is an ominous sign.


The most common test to identify a midline shift is the CT scan. However, in some cases, a CT scan is not possible because the patient is unstable, or because frequent measurements are wanted to track the progress of a bleed. In these situations, bedside sonography can also be used to diagnose and track the development of a midline shift.

There are three important structures evaluated when determining the presence of a midline shift: the septum pellucidum, the third ventricle, and the pineal gland.

  • The septum pellucidum: a thin membrane that runs directly down the center of the brain
  • The third ventricle: a space filled with cerebrospinal fluid that lies deep in the center of the brain
  • The pineal gland: a small gland that lies just behind the third ventricle

The locations of these three brain structures serve as reference points on a radiologic scan. If any of them are out of alignment, this indicates that pressure on one side of the brain is pushing the brain out of position.


The most important treatment when a midline shift is present is relieving the pressure that is pushing the brain off-center. If a collection of blood is the cause, such as a subdural hematoma, surgery will be needed to remove the blood clot and stop the bleeding.

Antibiotics are used to treat infection and steroids may be used to decrease inflammation and swelling.


A number of studies have examined the effects of midline shift on long-term outcomes. Since a midline shift happens due to bleeding and pressure, the amount of bleeding, the location of damage, and the overall level of pressure experienced by the brain are all important considerations.

When the brain moves, this causes trauma to other structures as they are pulled and pushed out of their natural position. The greater the midline shift, the more serious the complications and the greater the risk of death.

Frequently Asked Questions

  • What is the midline of the brain?

    The brain's midline is a grove that runs between both sides of the brain. It typically aligns with the midline of the body. 

  • What is a midline shift?

    A midline shift is when the natural centerline of the brain is pushed to the right or left. 

  • Is a midline shift in the brain bad?

    Yes. When the midline of the brain shifts, it indicates a significant increase in pressure in the brain. A midline brain shift is considered a medical emergency.

  • Can you survive a midline shift of the brain?

    Yes, people can survive a midline shift if the cause is relieved promptly. However, there is a possibility of long-term brain damage depending on the specific cause. The amount and location of the bleeding and the level of intracranial pressure all play a role in the damage. The greater the midline shift, the more likely it could cause lasting problems.

4 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Munakomi S, M Das J. Intracranial pressure monitoring. [Updated 2019 Sep 10]. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2019 Jan.

  2. Haydel MJ, Burns B. Blunt head trauma. In: StatPearls. Treasure Island (FL): StatPearls Publishing.

  3. Bartels RH, Meijer FJ, van der Hoeven H, Edwards M, Prokop M. Midline shift in relation to thickness of traumatic acute subdural hematoma predicts mortalityBMC Neurol. 2015;15:220. doi:10.1186/s12883-015-0479-x

  4. Motuel J, Biette I, Srairi M, et al. Assessment of brain midline shift using sonography in neurosurgical ICU patients. Crit Care. 2014;18(6):676. doi:10.1186/s13054-014-0676-9

By Eva Hvingelby, NP, PhD
Eva Hvingelby NP, PhD, is a nurse practitioner, researcher, educator, and health consultant specializing in trauma.