Arachnoid granulations

Arachnoid granulations, also known as arachnoid villi, are small protrusions of the arachnoid membrane (one of the three layers of the meninges that covers the brain and spinal cord) into the dural venous sinuses of the brain.

These structures play a crucial role in the drainage of cerebrospinal fluid (CSF) from the subarachnoid space into the venous system, thus maintaining the balance of CSF within the central nervous system.

Under normal circumstances, arachnoid granulations are asymptomatic and go unnoticed.

However, they can become enlarged and calcified, a condition known as 'pacchionian bodies,' and may sometimes be mistaken for pathological lesions on imaging studies.

These calcified granulations can be observed through imaging techniques such as MRI or CT scans, typically appearing as small, rounded structures within the dural sinuses.

In rare cases, large arachnoid granulations can cause obstruction of venous flow or be associated with conditions like idiopathic intracranial hypertension, which is characterized by increased intracranial pressure without an apparent cause.

Symptoms of such complications might include headaches, vision problems, and other neurological deficits.

Overall, while arachnoid granulations are generally benign and part of normal anatomy, awareness and accurate identification via appropriate imaging are important to differentiate them from other potential pathologies in the brain.

Education on this topic can aid healthcare professionals in making informed decisions about diagnosis and management.