Mudras (“to seal”)
(This is an excerpt from a University Of Metaphysical Sciences course at www.umsonline.org, please feel free to visit the school website)
A mudra used during meditation is called jnana mudra. This is the commonly seen mudra practiced by yogis sitting cross-legged or in the lotus posture with the fingers arranged in the “A-OK” sign and the back of the hand resting on the knee, inside of the hand turned upward. Sometimes the hands are turned downward, which is the easiest and most relaxed position. In this mudra, the thumb and index finger are curled until they touch tips, and the rest of the fingers are in an open, straight position.
Vishnu mudra is the same as described in the nadi shodhanam exercise where the index and middle fingers are curled inward, the thumb rests on the index and middle fingers and the other fingers are outstretched. However, this mudra need not be resting on the bridge of the nose except when practicing nadi shodhanam.
These are the two most commonly practiced mudras in pranayama. See the UMS Mudras course for more information on mudras, their positions, and uses.