From the eastern face of caturānana(chaturanana; the four-faced one) Brahmā (Brahma), emanated the major acts of yajña(yajna). Like the yajña-rituals called Ṣoḍaśī(Shodasi) and Ukthya, Atirātra (Atiratra) and Āptoryāma (Aptoryama) also emanated from his mouth. In Viṣṇupurāṇa (Vishnupurana), though the name of Āptoyāma is not separately mentioned, it is said that Atirātra was created from the western mouth of Brahmā; so we can also assume the emergence of Āptoryāma, rather indirectly.