Matsya Purana — The Ravi-Śayana
पूर्वोत्तराषाढयुगे च नाभिं त्वष्ट्रे नमः सप्ततरंगमाय तीक्ष्णांशवे च श्रवणे च कुक्षौ पृष्ठं धनिष्ठासु विकर्तनाय //
pūrvottarāṣāḍhayuge ca nābhiṃ tvaṣṭre namaḥ saptataraṃgamāya tīkṣṇāṃśave ca śravaṇe ca kukṣau pṛṣṭhaṃ dhaniṣṭhāsu vikartanāya //
In the paired nakṣatras Pūrvāṣāḍhā and Uttarāṣāḍhā, one should meditate upon the navel; obeisance to Tvaṣṭṛ, Lord of the sevenfold waves (rays). In Śravaṇa, one should meditate upon the belly; obeisance to Tīkṣṇāṃśu, the Sun of sharp rays. In Dhaniṣṭhā, one should meditate upon the back; obeisance to Vikartana, the radiant and scorching Sun.
This verse is not about Pralaya; it teaches a ritual-visualization (nyāsa) in which parts of the body are associated with specific nakshatras and solar epithets for worship.
It supports the king/householder’s dharma by prescribing disciplined daily worship—especially solar devotion—through precise mantra-salutations and meditative placement, reinforcing order (ṛta) and personal purity.
Ritually, it is a nyāsa/anga-vinyāsa style instruction: placing the deity’s presence on specific body loci while reciting names of Sūrya; such procedures are often paired with temple iconography and consecration routines in Purāṇic practice.