 The lower left hand is free, however Lord Vishnu idols generally have a Gada (Mace) in this hand.Yudhishthira after having a holy bath, installed the idols after immersing it in the Pushkarani (Pond), filling the Conch with its water and performed the first Pooja after installation

Hence, the pond at Thrichittat is named as - Amurtha Pushkarani, since the idol was immersed in it and as - Shankh Theertham, on the occasion of the pond's water filling the Conch, therefore, worshipping at Shankh Theertham, is considered equivalent to that of Sree Kovil (Sanctum Sanctorum of the Temple), and full darshanam is complete when both places are worshipped

Earliest references to this temple appear in the poems and hymns composed by the greatest of Alvar saints - Nammalvar, in circa 800 AD.Stone inscriptions in the temple date it back to the Second Chera Empire (800 - 1102 AD).