ArticlesAnatomyNeuroanatomyMeninges, ventricular system and subarachnoid space Falx cerebri

Author: Gordana Sendić, MD • Reviewer: Dimitrios Mytilinaios, MD, PhD
Last reviewed: October 30, 2023
Reading time: 8 minutes

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Definition and location of the falx cerebri.

Cerebral falx

Falx cerebri

Synonyms: none

The falx cerebri is a strong crescent-shaped sheet that represents an invagination of the meningeal layer of the dura mater into the longitudinal fissure, found between the medial surfaces of the cerebral hemispheres. This sheet descends in the midline of the brain, separates the cerebral hemispheres and incompletely divides the cranial cavity into right and left halves.

Anteriorly, the falx cerebri is attached to the crista galli of the ethmoid bone, and runs posteriorly in the sagittal plane, as far back as the internal occipital protuberance. Its posterior part blends with another dural fold called the tentorium cerebelli, which separates the occipital lobe of the brain from the underlying cerebellum.

This article will discuss the anatomy and function of the falx cerebri.

Contents

Anatomy

Blood supply

Relations

Function

Clinical relations

Subfalcine herniation

Sources

+ Show all

Dura mater

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Synonyms: Pachymeninx

The brain and spinal cord are enveloped by the meninges, which serve to protect them from mechanical trauma, provide support to blood vessels and a passageway for the cerebrospinal fluid (CSF). From innermost to outermost, the meninges consist of the following three layers: pia mater, arachnoid mater, and dura mater.

The dura mater is a strong, double-layered membrane, composed of the periosteal layer, which adheres to the periosteum of the neurocranium, and the meningeal layer, which surrounds the brain and spinal cord. In some regions and fissures of the brain, the meningeal layer of dura mater projects inwards to form four dural partitions: the falx cerebri, falx cerebelli, tentorium cerebelli, and sellar diaphragm.

Cerebral falx

Falx cerebri

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Synonyms: none

The falx cerebri is the largest of the four partitions of the dura mater, and represents an invagination of the meningeal layer of dura into the longitudinal fissure of the brain. This crescent-shaped sheet of tissue occupies this fissure and separates the two cerebral hemispheres. It begins anteriorly from the crista galli of the ethmoid bone, and runs in the midline along the entire internal surface of the cranium, and extends posteriorly all the way to the internal occipital protuberance.

The anterior part of the falx cerebri is narrow and thin, and is fixed to the crista galli. Its convex superior margin is attached to the lips of the groove for superior sagittal sinus, while its concave inferior margin is free. The posterior part of the falx cerebri is broad and attaches to the internal occipital protuberance, while blending with the superior surface of the tentorium cerebelli.

How well do you know the anatomy of the meninges of the brain? Test yourself with this quiz.

Anterior ethmoidal artery

Arteria ethmoidalis anterior

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Synonyms: Arteria ethmoidea anterior

Similarly to the dura mater, the falx cerebri is supplied by branches of the maxillary, internal carotid, ascending pharyngeal and vertebral arteries.

More specifically, the anterior part of the falx cerebri is supplied by the anterior division of the middle meningeal artery, anterior ethmoidal and pericallosal arteries.

The posterior part of the falx is supplied by the posterior division of the middle meningeal artery, meningohypophyseal trunk of the internal carotid artery, and posterior cerebral, pericallosal, and posterior meningeal arteries.

Struggling to understand the meninges and dural septa? Make your life easier and learn all the parts of the brain with our diagrams and quizzes!

The falx cerebri contributes to the formation of several dural venous sinuses:

The falx cerebri separates the cerebral hemispheres and houses the dural sinuses, into which the blood and cerebrospinal fluid drain. However, it’s exact function is not entirely certain. The function of the falx cerebri may be to constrain the brain and limit its displacement and rotation inside the cranium. Being a dural fold, the falx is stiffer than the surrounding tissue and plays an essential role in supporting the brain by suppressing the movements of the brain inside the skull during acceleration.

In addition, it is thought that the dural folds, and especially the falx cerebri and the tentorium cerebelli, play an important role in the development and functional loading of the cranium. In other words, dural folds determine the cranial suture sitesand their absence is accompanied by a lack of suture formation.

Now that you’ve mastered the falx cerebri, check out the study unit below to find out more about the meninges of the brain, or take the quiz to consolidate what you learned so far!

Clinical relations Subfalcine herniation

Subfalcine herniation, also known as cingulate herniation, is the most common type of cerebral herniation. It can be caused by anything that increases the intracranial pressure in one compartment of the brain, such as a tumor, localized hemorrhage (e.g. epidural hematoma), or an increase in cerebrospinal fluid (CSF) volume. In each case, the mass creates a compressing effect and pushes the brain tissue in a downward and medial direction, causing the displacement of the ipsilateral cingulate gyrus under the free margin of the falx cerebri.

The herniated cingulate gyrus can compress the ipsilateral anterior cerebral artery resulting in contralateral leg weakness. If the herniation occurs in the dominant hemisphere, the cingulate gyrus can also compress the arcuate fasciculus. Since this fasciculus connects the Broca’s and Wernicke’s areas, its compression can cause different types of aphasias.

Sources

All content published on Kenhub is reviewed by medical and anatomy experts. The information we provide is grounded on academic literature and peer-reviewed research. Kenhub does not provide medical advice. You can learn more about our content creation and review standards by reading our content quality guidelines.

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