Mudras are unique to Indian dance. They also form a branch of Yoga and prove the shared territory between Indian dance and Yoga and possibly a common origin. The hatha yoga pradipika and other yogic texts consider mudra to be a Yoga anga- an independent branch of yoga -requiring a very subtle awareness. Mudras can be static or moving. They can involve the hands or the entire body. Hasta mudras are the most visible use of mudras in Indian dance.
The nadis and chakras constantly radiate prana which normally escapes from the body and dissipates into the external world. By creating barriers within the body through the practise of mudra, the energy is directed within.
Each mudra sets up a different link and has a correspondingly different effect on the body, mind and prana.
Prana is both breath and energy. Hand mudras redirect the prana being emitted by the hands back into the body. Mudras which join the thumb and index finger engage the motor cortex at a very subtle level, generating a loop of energy which moves from the brain down the hand and then back again.
Mudras also operate as a codified language that supplement storytelling.