Nadis are the astral tubes made up of astral matter that carry psychic currents, the Sanskrit term ‘Nadi’ comes from the root ‘Nad’ which means ‘motion’.
It is through these Nadis (Sukshma, subtle passages), that the vital force or Pranic current moves or flows, since they are made up of subtle matter they cannot be seen by the naked physical eyes and you cannot make any test-tube experiments in the physical plane.
These Yoga Nadis are not the ordinary nerves, arteries, and veins that are known to the Vaidya Shastra (Anatomy and Physiology), Yoga Nadis are quite different from these.
The body is filled with innumerable Nadis that cannot be counted, different authors state the number of Nadis in different ways, i.e., from 72,000 to 3,50,000.
When you turn your attention to the internal structure of the body, you are struck with awe and wonder, because the architect is the Divine Lord Himself who is assisted by skilled engineers and masons — Maya, Prakriti, Visva Karma, etc.
Nadis play a vital part in this Yoga, Kundalini when awakened, will pass through Sushumna Nadi and this is possible only when the Nadis are pure.
Therefore, the first step in Kundalini Yoga is the purification of Nadis, a detailed knowledge of the Nadis and Chakras is absolutely essential. Their location, functions, nature, etc., should be thoroughly studied, the subtle lines, Yoga Nadis, have an influence on the physical body, and the gross nerves and plexuses have a close relationship with the subtle ones.
Since the physical centers have a close relationship with the astral centers, the vibrations that are produced in the physical centers by prescribed methods, have the desired effects in the astral centers.
Whenever there is an interlacing of several nerves, arteries, and veins, that center is called “Plexus.” The physical material plexuses that are known to the Vaidya Shastra are: — Pampiniform, Cervical, Brachial, Coccygeal, Lumbar, Sacral, Cardiac, Esophageal, Hepatic Pharyngeal, Pulmonary, Lingual Prostatic Plexus, etc.
All the Nadis spring from the Kanda, it is in the junction where the Sushumna Nadi is connected with the Muladhara Chakra, some say, that this Kanda is 12 inches above the anus.
The Ida and Pingala represent the basic duality in the existence, it is this duality which we traditionally personify as Shiva and Shakti, or you can simply call it masculine and feminine, or it can be the logical and the intuitive aspect of you, it is based on this that life is created.
Without these two dualities, life wouldn’t exist as it does right now, in the beginning, everything is primordial, there is no duality, but once creation happens, there is duality.
When we say masculine and feminine, we are not talking in terms of sex — about being male or female — but in terms of certain qualities in nature.
Certain qualities in nature have been identified as masculine. Certain other qualities have been identified as feminine.
You may be a man, but if your Ida is more pronounced, the feminine may be dominant in you, you may be a woman, but if your Pingala is more pronounced, the masculine may be dominant in you.
Fundamentally, Sushumna is attribute-less, it has no quality of its own, it is like empty space.
If there is empty space, you can create anything you want. Once energies enter into Sushumna, we say you attain to Vairagya, “Raga,” which means color. “Vairag,” means no color, you have become transparent.
If you have become transparent, if what is behind you is red, you turn red too, if what is behind you is blue, you turn blue too, you are unprejudiced.
Wherever you are, you become a part of that, but nothing sticks to you, only if you are like this, only if you are in a state of Vairag, then you will dare to explore all dimensions of life when you live here.
If for some reason the outside situation goes crazy, you will also go crazy in reaction to that because that is the nature of Ida and Pingala. It is reactive to what is outside.
But once the energies enter into Sushumna, you attain a new kind of balance, an inner balance where whatever happens outside, there is a certain space within you that never gets disturbed, which is never in any kind of turmoil, which cannot be touched by the outside situations.
Only if you create this stable situation within yourself, you will dare to scale the peaks of consciousness.
