Shiva, Ganga and third eye

Ganga, the holiest of the holy rivers, flows from the matted hair of Shiva. Shiva allowed an outlet to the great river to traverse the earth and bring purifying water to human beings. The flowing water is one of the five elements, which compose the whole Universe and from which earth arises. The origin of the Ganga from the head of Lord Shiva seems to be related to the flow of the cerebrospinal fluid (CSF) arising from the ventricles flowing in the direction of gravity towards the spinal column. Ganga circulates in the matted hairs of Lord Siva and then flows to the earth and finally drains to the great ocean . In the same way as CSF circulates into the ventricle and finally drains into the venous sinuses. As CSF preserves the normal homeostasis of the structure of the brain so as Ganga preserves the normal environmental balance of the earth around it. We presumed that that representation of the flow of CSF in the literature of ancient Hinduism shows their knowledge about brain and the dynamics of CSF. Moreover, the flowing nature of holy Ganga represents continuous formation of CSF by the brain.

The third eye of Shiva on his forehead is the eye of wisdom. It is the eye that looks beyond the obvious. The third eye of Shiva is also popularly associated with its untamed energy, which destroys the evil doers and sins. He governs time, i.e., the day and night cycle. The pineal body of brain is also termed as the third eye and is associated with the circadian rhythm of the body. 

R. Kumar, Devendrakumar Gupta in “Shiva: supreme God of all in Saivism”