A very interesting, yet little understood gland is the pineal gland. The function of this gland is not certain and baffled medical scientists are still trying to unravel its secrets. It is located in the centre of the brain, and is pea-sized. Many people have regarded it as an organ that has lost its purpose in the evolutionary growth of man. That is, that it had a use when man was in a more primitive state. However, this is most unlikely, since it has an extremely high blood flow. Per unit weight, it has the second largest blood flow of all the organs in the body, being second only to the kidneys. This suggests that it has a most important functional duty, which has not yet become obvious to scientists. In time, its secrets will be revealed. Though its physiological role cannot be definitely ascertained, it is regarded as an endocrinal gland.
In yoga and other mystical systems throughout the world, the pineal is regarded as the physical equivalent of the third eye – the intuitive eye of revelationary knowledge. It is the eye of illumination. It is the physical organ that focuses knowledge or experience of more subtle realms of being into the brain for comprehension by the individual. It is analogous to a transistorized valve of a radio which picks up the electromagnetic waves from a far-off broadcasting station. This is not really a very good analogy, but it indicates what we are trying to convey. The pineal gland is the organ in the brain through which the individual can experience the more subtle levels of experience. It is also associated with the ajna chakra, the psychic centre that is concerned with psychic powers such as telepathy, clairvoyance, etc. It is through the pineal gland that psychic signals or phenomena are channelled into the brain and the body. It is the physical organ, associated with the more subtle ajna chakra, by which two individuals can communicate in a more subtle and direct manner.
Perfect functioning of the pineal is most important in yoga and can be brought about by sirshasana as well as other yogic techniques, which improve its large blood requirements and harmonize its relationship with the rest of the body and brain.