Hasta Karaṇas -
Nṛttaratnāvalī - Language: Sanskrit
The Nṛttaratnāvalī by Jāyana (also called Jāya Senāpati) is in Sanskrit, and written down in Telegu text. It dates from the Kātatīya Dynasty, which covered what is now modern day Telegana. The rulers where worshippers of the goddess Kātatī and this was a golden age for the region, with a lot of writing on the arts and other intellectual concepts. Jāyana wrote 3 texts on dance, however the Nṛttaratnāvalī is the one that survives. The Gītaratnāvalī and Vādyaratnāvalī did not survive. The work divides itself into 8 chapters - 4 devoted to marga - the classical format that traces to the long linneage of historical treatises, and 4 desi dance which isn't within this cannon and is generally described as regional and popular, which the author then describes meticulously. This kind of division starts at this time period.
If the hands are brought from side to the chest and the fingers curled in movement so that the forefinger takes the lead it is the apaveṣṭita according to experts in nrtta.
In the same way, while straightening the fingers if the hand turns upwards and moves to the sides from the chest it is udveṣṭita.
One hasta is bent inwards with apavestita and the other opened outwards with udveṣtita repeated alternately,
The hasta in prone position is moved from the sides to the chest while the fingers curl inwards following the little finger’s lead. This is vyāvartana as the erudite say.
In the same way when the hand is moved from the chest to the sides in prone position, straightening the fingers as the little finger leads is called parivartitam as opined by those in knowledge of the nuances of dance