Skandapurana 16.107.30

16.107.30

takāraṃ vinyasenmūrdhni sakāraṃ mukhamaṇḍale ..
vikāraṃ kaṃṭhadeśe tu tukāraṃ cāṃgasaṃdhiṣu .. 7.1.107.30 ..

He should place the syllable 'tat' on the head, the syllable 'sa' on the region of the face, / the syllable 'vi' in the region of the throat, and the syllable 'tu' on the joints of the limbs;