Tentorial notch

Anatomical structure in the human brain

Diagram of the tentorial notch

The tentorial notch, also known as the incisura tentorii, is an important anatomical structure in the human brain. It is an opening in the tentorium cerebelli, a fold of dura mater that separates the cerebrum from the cerebellum. The tentorial notch allows for the passage of the brainstem, specifically the midbrain, from the posterior cranial fossa to the supratentorial compartment.

Anatomy

The tentorial notch is located at the anterior edge of the tentorium cerebelli. It is bordered by the free edge of the tentorium, which forms a semicircular opening. The notch is situated above the pons and the medulla oblongata, and it surrounds the midbrain.

Relations

The tentorial notch is closely related to several critical structures:

• The midbrain passes through the notch, connecting the diencephalon with the pons.
• The oculomotor nerve (cranial nerve III) runs along the edge of the tentorial notch.
• The posterior cerebral artery and the superior cerebellar artery are also in close proximity to the notch.

Clinical Significance

The tentorial notch is clinically significant because it is a common site for brain herniation.

Herniation

Brain herniation can occur when there is increased intracranial pressure, causing brain tissue to be displaced through the tentorial notch. This can lead to compression of the midbrain and other vital structures, resulting in life-threatening conditions.

Symptoms

Compression of the midbrain at the tentorial notch can lead to:

• Altered consciousness
• Abnormal pupillary reflexes
• Decerebrate posturing

Related Pages

• Tentorium cerebelli
• Brain herniation
• Midbrain
• Dura mater