Śivasaṃhitā 4.42

This verse marks a technical convergence point: when Mūla-bandha reaches its perfection, prāṇa and apāna fuse spontaneously, and that fusion is precisely Yonimudrā — the great uterine seal that contains energy at its source. The sequence Mūla-bandha → union of prāṇa-apāna → Yonimudrā describes a progression of increasing depth.

Sampūrṇahṛdaya — ‘of complete heart, full’ — is the epithet of the yogi who has matured in practice; sampūrṇa (completely full, replete) qualifies an internal disposition that is not perfectionism but total availability. Yonimudrā — ‘seal of the source’ — is here not merely a technique but the resultant state of the union of opposing energies: ascending apāna and descending prāṇa neutralize each other in the center of the subtle body.

The identification between Mūla-bandha and Yonimudrā as successive forms of the same technical act is specific to the Śivasaṃhitā and does not appear with equal clarity in the Haṭhapradīpikā. This reflects the more explicitly tantric orientation of the text: while the Haṭhapradīpikā tends to treat each technique in a relatively autonomous manner, the Śivasaṃhitā emphasizes the fluidity between techniques and the emergence of deeper states from more superficial ones.