Nadi

The Sanskrit nāḍī derives from nāḍa, a "reed," "tube" or "hollow stalk," and so literally means a channel, conduit or flowing passage. The image is of something through which a current runs — here, the current of prāṇa, the vital force, moving within the subtle body rather than within any visible vessel.

In the yogic model the body is threaded by countless nāḍīs — many texts speak of seventy-two thousand — along which prāṇa flows. Three are principal: iḍā, running to the left, piṅgalā to the right, and suṣumnā, the central channel following the spinal axis, into which the tradition seeks to draw prāṇa.

The Haṭha Yoga Pradīpikā describes cleansing and balancing the nāḍīs through nāḍī-śodhana, alternate-nostril breathing, as preparation for deeper practice; the Gheraṇḍa Saṃhitā treats purification in a similar spirit. Iḍā and piṅgalā are linked to cool and warm, lunar and solar qualities of breath, energy and temperament.

You engage the nāḍīs most directly through breath. Alternate-nostril breathing is said to balance iḍā and piṅgalā, encouraging prāṇa to enter the central suṣumnā. Practitioners often report a steadier, more even state of mind after such work — the practical reason these techniques have held a lasting place in the tradition.

Nāḍīs are part of a subtle-body map, not physical anatomy. They are not nerves, veins or arteries, and no dissection reveals them; equating them with bodily structures confuses two different frameworks. Hold the model as a traditional aid to contemplative practice rather than as a physiological or medical claim about the body.