Nyāsa or purification of limbs is an important aspect of many a ritualistic process like pūjā (worship), japa (repetition of divine name) and pārāyaṇa (ceremonial recitation of scriptures or sacred texts). Out of seven such nyāsas, the aṅganyāsa and the karanyāsa are most common.
In the karanyāsa, the fingers of both the hands are purified simultaneously to the accompaniment of appropriate mantras. First, the thumbs are rubbed by the tips of the index-fingers from bottom to top with the mantra ‘aṅguṣṭābhyaṁ namaḥ’. Then the thumbs do the rest of the work in a similar manner, to the other four fingers, the mantras being changed according to the fingers touched.