Matsya Purana — Dynastic Genealogies: Paurava–Anu Lines
तस्यापानं विना चैव योग्यभावो भविष्यति तस्माद् दीर्घतमाङ्गेषु कुक्षौ स्पृष्ट्वेदम् अब्रवीत् //
tasyāpānaṃ vinā caiva yogyabhāvo bhaviṣyati tasmād dīrghatamāṅgeṣu kukṣau spṛṣṭvedam abravīt //
“Even without apāna, the downward-moving breath, it will still become fit for the task.” Therefore, touching his own belly with his long limbs, he spoke these words.
It sits within the Pralaya (flood) narrative and emphasizes “fitness for the task” even under unusual conditions—suggesting extraordinary, divinely enabled capability during cosmic crisis rather than ordinary biological limitation.
In the Manu-centered flood episode, the underlying ethic is preparedness and steadiness: even when normal supports are absent, one must remain ‘yogya’ (fit) to carry out dharma—protecting life, preserving tradition, and following divine instruction.
No direct Vāstu or temple-building rule appears here; the technical note is yogic/ritual physiology (apāna and the belly), often invoked in Purāṇic literature to signal controlled vital energies and extraordinary efficacy.