Cisterna magna

Diagram of the cisterna magna

The cisterna magna, also known as the cerebellomedullary cistern, is one of the largest subarachnoid cisterns in the human brain. It is located between the cerebellum and the medulla oblongata, and it is an important structure in the central nervous system for the circulation of cerebrospinal fluid (CSF).

Anatomy

The cisterna magna is situated in the posterior cranial fossa, beneath the tentorium cerebelli. It is bordered superiorly by the cerebellum, inferiorly by the foramen magnum, and anteriorly by the medulla oblongata. The cisterna magna is continuous with the spinal subarachnoid space and communicates with the fourth ventricle of the brain via the foramen of Magendie.

Function

The primary function of the cisterna magna is to act as a reservoir for cerebrospinal fluid. CSF flows from the ventricular system of the brain into the cisterna magna, where it then circulates around the brain and spinal cord. This fluid provides a cushioning effect, protecting the brain and spinal cord from injury, and also helps in the removal of metabolic waste products from the central nervous system.

Clinical Significance

The cisterna magna is often evaluated in neuroimaging studies, such as MRI and CT scans, to assess for abnormalities. Enlargement of the cisterna magna can be associated with conditions such as Dandy-Walker malformation, while a reduction in size may be seen in cases of Chiari malformation.

In some medical procedures, such as cisternal puncture, the cisterna magna is accessed to obtain cerebrospinal fluid for diagnostic purposes. This procedure is less common than lumbar puncture but may be used in certain clinical situations.

Related Pages

• Cerebrospinal fluid
• Subarachnoid space
• Fourth ventricle
• Dandy-Walker malformation
• Chiari malformation