nadis

Tantra and Kundalini Yoga
Nadis
In addition to the seven chakras of the subtle body, the Tantrashave described a network of subtle channels known as Nadis.According to the tantric treatise Shiva Samhita, there arefourteen principal nadis. Of these, Ida, Pingala and Sushumnaare considered the most important.
Ida is the left channel. Ida is white, feminine, cold, representsthe moon and is associated with the river Ganga (Ganges).Originating in Muladhara, Ida ends up in the left nostril.
Pingala is the right channel. Pingala is red, masculine, hot,represents the sun and is associated with the river Yamuna.Originating in Muladhara, Pingala ends up in the right nostril.
Sushumna is the central channel and is associated withthe river Saraswati. Running up the body from just below Muladhara chakra to Sahasrara chakra at the crown of the head.
Muladhara is the meeting place of the three main nadis and is known as Yukta Triveni (Yukta : "combined", tri : "three", veni : "streams"). In Muladhara, Shakti, the static unmanifested Kundalini, is symbolized by a serpent coiled into three and a half circles around the central axis Svayambhu-linga at the base of the spine. The serpent lies blocking the entrance to Sushumna, the central channel with his mouth. Sushumna remains closed at its lower end as long as Kundalini is not awakened.The technique of Kundalini Yoga consists in using Prana (the vital air), guiding its circulatory movement through Ida and Pingala down to the base of the spine into the space where Kundalini lies coiled. Shakti Kundalini will then awaken and rise up Sushumna, energizing the seven chakras.
From Muladhara chakra, Ida and Pingala alternate at each chakra until they reach Ajna chakra where they meet again with Sushumna.In Ajna chakra the meeting of the three main nadis is called Mukta Triveni (Mukta : "liberated"). Continuing beyond Ajna chakra, Ida and Pingala end in the left and right nostrils respectively.
Once the Kundalini Shakti has ascended through Sushumna to Sahasrara, the highest psychic center at the crown of the head, it is made to reverse its course and return to rest in the base center again.