I am quoting this from a Facebook post by Nubia Teixeira, jau Uttal's wife, yogini and exquisite dancer. From wholistic sound to wholistic dance- dance as an expression of wholeness and life.

Hands are filled with the mystery of creation. ....Hands are an extention of the Heart Center and can express all the feelings and forms in the universe. ViniYoga is the science of Hand Gestures.

The Abhinaya Darpan mentions that the dancer should sing the song by the throat, express the meaning of the song through hand gestures, show the state of feelings by eyes and keep track of the time with feet.
From the Natya Shastra, a text on the arts:
"Yato hasta stato drishti"..."Where the hand is, the eyes follow"
"Yato drishti stato manaha"..."Where the eyes go, the mind follows"
"Yato manaha stato bhava"..."Where the mind is, there is the feeling"
"Yato bhava stato rasa"..."Where the feeling is, there is mood"
So vast is the hand gestures that it covers almost all the aspects of human life and the entire universe.
Hence 'Mudras' form a distinct code language and bring unique poetic element while performing abhinaya and thus the language of the mudras enables the dancer to express practically anything and everything.
Om Namah Shivaya !!!!!