Basal cisterns

Basal Cisterns

The basal cisterns are a group of interconnected subarachnoid spaces located at the base of the brain. These cisterns are filled with cerebrospinal fluid (CSF) and play a crucial role in cushioning the brain, facilitating the circulation of CSF, and providing a pathway for cranial nerves and blood vessels.

Anatomy

The basal cisterns are situated in the subarachnoid space, which is the area between the arachnoid mater and the pia mater. The major basal cisterns include:

• Cisterna magna: Also known as the cerebellomedullary cistern, it is located between the cerebellum and the dorsal surface of the medulla oblongata. It is one of the largest cisterns and is often accessed during procedures to obtain CSF samples.

• Pontine cistern: Located ventral to the pons, this cistern contains the basilar artery and is continuous with the interpeduncular cistern.

• Interpeduncular cistern: Situated between the cerebral peduncles, it contains the circle of Willis and the oculomotor nerves.

• Chiasmatic cistern: Found around the optic chiasm, it is involved in the circulation of CSF around the optic nerves.

• Ambient cistern: Located lateral to the midbrain, it connects the interpeduncular cistern with the quadrigeminal cistern.

• Quadrigeminal cistern: Positioned posterior to the midbrain, it is associated with the superior and inferior colliculi.

Function

The basal cisterns serve several important functions:

• Cushioning and Protection: The CSF within the cisterns acts as a cushion, protecting the brain from mechanical injury.

• CSF Circulation: The cisterns are integral to the circulation of CSF, which is essential for maintaining intracranial pressure and removing metabolic waste.

• Pathway for Neurovascular Structures: The cisterns provide a pathway for cranial nerves and blood vessels, facilitating communication between different parts of the brain.

Clinical Significance

The basal cisterns are often evaluated in neuroimaging studies, such as CT and MRI scans, to assess for conditions such as:

• Subarachnoid hemorrhage: Blood can accumulate in the basal cisterns following a rupture of an aneurysm, leading to increased intracranial pressure and potential brain damage.

• Hydrocephalus: Obstruction of CSF flow in the basal cisterns can lead to hydrocephalus, a condition characterized by an abnormal accumulation of CSF in the brain.

• Brain herniation: Compression of the basal cisterns can indicate brain herniation, a life-threatening condition where brain tissue is displaced due to increased intracranial pressure.

Also see

• Cerebrospinal fluid
• Subarachnoid space
• Cranial nerves
• Circle of Willis