Increasing awareness about yoga and authentic experiences of its positive effects upon one's well being, have also created interest in the scientific foundation of yoga. The asana, pranayam, bandha and mudra taught under different disciplines of yoga were indeed derived from deeper understanding of the workings of the brain, the nervous system, the nuclei of biorenergy and the channels of its flow in different parts of the body and the detailed anatomy of the body as visualized by the sagacious acumen of the Vedic seers (Rishis). In this tworpart article we shall introduce the elementary scientific aspects and practices of some of the hand mudras. Word meaning of "mudra" refers to "gesture" or attitude. The science of yoga also describes these as a means of controlling or altering the mood by reorienting or focusing the flow of prana (vital spiritual energy) in desired direction or concentrating it at specific extrasensory nuclei inside the body. This is why modern yoga literature also explains mudras as "seal" or "circuit by pass" for vital energy currents. Once the gross blockages and untoward assimilations of the physical and energy bodies are eliminated by thorough yoga practices of asana, pranayam, and bandha, in the advanced stages, the yoga disciples can attain extraordinary effects of self controlled flow of prana in the brain and the central nervous system with the help of mudras. Because, as explained by Swami Satyanand Saraswati in his classic books on Yoga r "mudras provide a means to access and influence the unconscious reflexes and primal, instinctive habit patterns that originate in the primitive areas of the brain around the brain stem. They establish a subtle, non intellectual connection with these areas. Each mudra sets up a different link and has a correspondingly different effect on the body, mind and prana". The palms and fingers of the hands contain many nerve root endings, which constantly emit bioelectric energy. Touching or pressing specific points on the fingers and the thumb folded in specific manner completes an energy circuit and activates specific nerve or nerve bundle and thus triggers specific signals. This is what makes certain mudras so suitable for certain kinds of mental and physical effects. The importance of specific points and portions of hand (and other parts of the body) can also be seen in healing effects of acupressure on the physical body. Being emanated primarily from the science of spirituality, the yoga practices pertain to consciousness force. The advanced effects of yoga, and of the hand mudras in particular are therefore associated with mental refinement, deep meditation and spiritual conditioning. However, like the asanas, in elementary practices as well, when one properly practices these as physical exercises, the mudras induce soothing effects on the mind body system. In this article we shall consider some such elementary aspects. While discussing the psycho neural (hence psycho physical too) effects of hand mudras, it is worth noting that the ancient science of yoga relates the fingers and thumbs with the Panca Tatvas1 r the five basic elements. The thumb corresponds to the source of balancing the flow of agni tatva. The vayu tatva is controlled by the fourth (or the index) finger. The role of the middle finger in the mudras is for regulating the akasa tatva in the body. The keys of regulating the poithvi and the jala tatvas lie in the ring finger and the little finger respectively. Harmonious proportion of these elements helps in natural maintenance of a vigorous body and a happy mind. Let us look at some of the hand mudras taught and practiced under Hathayoga for sustaining good health and mental calm by balancing the levels and intensities of the panca tatvas.

- courtesy Akhand Jyoti