GENERAL HISTOLOGY

Detailed explanation-1: -The subarachnoid space consists of the cerebrospinal fluid (CSF), major blood vessels, and cisterns . The cisterns are enlarged pockets of CSF created due to the separation of the arachnoid mater from the pia mater based on the anatomy of the brain and spinal cord surface.

Detailed explanation-2: -CSF flows from the lateral ventricles to the third ventricle via the foramen of Monro. From here, it flows across the cerebral aqueduct of Sylvius to the fourth ventricle and onto the subarachnoid space through the apertures of Magendie and Luschka [3].

Detailed explanation-3: -The CSF from the subarachnoid space is eventually reabsorbed through outpouchings into the superior sagittal sinus (SSS) known as the arachnoid granulations. Arachnoid granulations act as an avenue for CSF reabsorption into the blood circulation through a pressure-dependent gradient.

Detailed explanation-4: -The subarachnoid space is the interval between the arachnoid membrane and the pia mater. It is occupied by delicate connective tissue trabeculae and intercommunicating channels containing cerebrospinal fluid (CSF) as well as branches of the arteries and veins of the brain. The cavity is small in the normal brain.