By Heidi Moawad, MD 

Updated on October 19, 2023

 Medically reviewed by Brigid Dwyer, MD

 Fact checked by Nick Blackmer

A middle cerebral artery (MCA) stroke occurs when blood flow from the MCA, one of the largest arteries of the brain, is suddenly interrupted (ischemia) or altogether stopped (infarction). The loss of blood flow causes tissue death, leading to serious and potentially permanent brain injury.

MCA strokes are most often the result of a blood clot that travels from outside the brain, such as from the heart or carotid artery, and causes a partial or complete blockage of the artery. However, an MCA stroke can also be caused by a ruptured artery. This is known as a hemorrhagic stroke.

This article takes a closer look at the MCA as well as the symptoms and causes of MCA strokes. It also explains how MCA strokes are diagnosed and treated and what to expect during rehabilitation.

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What Is the Middle Cerebral Artery?

The arteries in your brain come in symmetrical pairs. Each one has a left and right artery. The MCAs are vital blood vessels that branch off from the internal carotid arteries.

The internal carotid arteries are branches of the common carotid arteries. Those are large blood vessels in your neck.

The MCA is the largest branch of the internal carotid arteries. It can be involved in large strokes.

What Does the MCA Do?

Arteries in the brain carry blood that’s rich in oxygen and nutrients to the brain.¹ Each artery supplies a different section of the brain. That section is called the “territory” of that artery.

The MCAs supply a large territory in the brain that is involved in:²

• Processing sensory information related to touch, taste, and temperature

• Processing audio and encoding memory

• Aiding communication between areas of the brain

• Movement, expressive language, and the ability to work toward a goal

When blood flow to these areas is impaired, they have a hard time carrying out their functions.

 Middle Cerebral Artery Anatomy and Function

MCA Stroke Symptoms

MCA strokes are the most common type. Their symptoms are the ones people usually associate with strokes, such as:

• Weakness and/or numbness on one side

• Facial droop

• Language deficits

An MCA stroke may also cause:

• Sensory deficits

• Visual defects

These affect the opposite side of the body from the artery. Thus, a stroke in the right MCA causes symptoms on the left side of the body.

How to Tell if Someone Is Having a Stroke

The acronym BE FAST is often used by health educators to describe stroke symptoms affecting balance, eyes, face, arm, speech, and time. Call 911 or seek emergency care if you or someone else experiences:³

• Sudden loss of balance on one side

• Vision changes in one eye or double vision

• One-sided facial drooping

• Loss of function or sensation in one arm

• Slurred speech

• Trouble finding a word or getting words out

 How to Recognize a Stroke and What to Do

Click Play to Learn All About MCA Strokes

This video has been medically reviewed by Chris Vincent, MD.

Causes

The MCA is a large blood vessel. Large-vessel strokes affect more of the brain than strokes in small vessels. If the MCA itself is blocked, the result is a large-vessel stroke that affects its entire territory.

If only a small branch of the MCA is blocked, it causes a small-vessel stroke. This impacts a small section of the MCA’s territory and is often less serious.

MCA strokes are generally caused by a blood clot that travels from outside the brain. Typically, it’s from the heart or carotid artery. Then the clot gets lodged in the MCA and blocks blood flow.

This is called an embolic stroke. This type of stroke can sometimes be caused by other debris in the bloodstream, such as plaque that has broken off from an atherosclerotic plaque.⁴

When the clot causing the blockage originates in the arteries of the brain, the stroke is called a thrombotic stroke.

Risk factors for MCA strokes include:⁵

• Heart disease

• Carotid artery disease

• General stroke risk factors such as high cholesterol, hypertension, and diabetes

Diagnosis

MCA strokes are among the most easily recognized types of stroke.

Even so, your healthcare provider will likely use multiple labs and tests to confirm the diagnosis. These may include:⁶⁷

• A neurological exam to determine affected brain regions

• Electrocardiogram (EKG) to check electrical conduction of the heart, which may be irregular and associated with the cause of the stroke

• Lumbar puncture (spinal tap) to check for hemorrhagic stroke (rupture of a weakened blood vessel)

• Blood tests to look for known risk factors, including clotting disorders, high cholesterol, and diabetes

• Computed tomography (CT) scan to quickly check for a brain bleed

• CT angiography, a common follow-up study after CT to find a blood vessel blockage

• Magnetic resonance imaging (MRI) or MR angiography (MRA) can help provide insight about the cause of the stroke and detect any related brain tissue damage

Other tests and imaging may be performed depending on your symptoms.

 How Stroke Is Diagnosed

Treatment and Rehabilitation

Treatment for an MCA stroke can be divided into two parts: initial treatment and rehabilitation.

Initial Treatment for MCA Stroke

Urgent treatment may include:

• Tissue plasminogen activator (tPA) or tenecteplase, medications that can dissolve blood clots⁸

• Other blood thinners

• Careful management of blood pressure, blood sugars, electrolytes, and fluids

• Surgery to remove pressure on vital brain regions

MCA Stroke Rehabilitation

Rehabilitation after a stroke can be intensive and prolonged. It may involve physical, occupational, and speech therapy. It's recommended that those who qualify and have access to services in an inpatient rehabilitation facility receive care there in preference to a skilled nursing facility.⁹

Summary

Blocks or ruptures in the MCA lead to MCA strokes. The resulting loss of blood, oxygen, and nutrients can cause brain damage and impair function in the regions that get blood from the MCA.

Treatment includes blood thinners, surgery to relieve pressure, and management of several vital signs. Recovery may involve multiple types of therapy, depending on the symptoms. Recovery from an MCA stroke may take some time, particularly if the entire MCA was blocked, resulting in a large stroke.

Long-term recovery and rehabilitation may take months or even years. However, a good recovery is possible even from very serious strokes. Most people who have an MCA stroke are able to regain some function.

By Heidi Moawad, MD

Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.