Ida, Pingala and Sushumna
Amongst these ducts or nadis, three are of the utmost importance: the Medullar Sushumna, which interpenetrates the cerebrospinal axis from the perineum to the juncture of the lamboid and sagittal suture of the cranium, and it is associated with both nostrils being open and free to the passage of air. The 'lunar Serpentine Ida' of the left side, of a pale color, negative polarity. It is associated with feminine attributes, the Yin element of Chinese philosophy, and an open left nostril; the solar Serpentine Pingala of the right side, red color, positive polarity. It is associated with masculine attributes, the Yang element of Chinese philosophy, and an open right nostril. Those are the main nadis, but in some tantric texts more than 72,000 nadis are cited. They all start from the central channel of the chakras to the periphery, where they gradually become thinner.
The Sat-Cakra-Nirupana, one of the earliest text on nadis and chakra, explicitly refer to these three main nadis, calling them Sasi, Mihira, Susumna.
In the space outside the Meru,the right apart from the body placed on the left and the right, are the two Nadis, Sasi and Mihira. The Nadi Susumna, whose substance is the threefold Gunas, is in the middle. She is the form of Moon, Sun, and Fire even water also; Her body, a string of blooming Dhatura flowers, extends from the middle of the Kanda to the Head, and the Vajra inside Her extends, shining, from the Medhra to the Head.
Sushumna (alternatively known as Susumna) Nadi connects the base chakra to the crown chakra. It is very important in Yoga and Tantra in general. Alternative medicine also refers to Sushumna sometimes. In Raja Yoga or Yoga of Patanjali, when the mind is quietened through Yama, Niyama, Asana and Pranayama the important state of Pratyahara begins. A person entering this state never complains of Dispersion of Mind. This is characterised by observing the movements/jerks in Sushumna, the central canal in the subtle body. The movements indicate the flow of Prana through the central canal and in the process, the sushumna makes the way for the ascent of Kundalini.
Pingala is associated with solar energy. The word pingala means "tawny" in Sanskrit. Pingala has a sunlike nature and male energy. Its temperature is heating and courses from the left testicle to the right nostril. It corresponds to the river Yamuna. The Ida and Pingala nadis are often seen as referring to the two hemispheres of the brain. Pingala is the extroverted, solar nadi, and corresponds to the left hand side of the brain. Ida is the introverted, lunar nadi, and refers to the right hand side of the brain.
Ida is associated with lunar energy sometime it is based on solar energy. The word ida means "comfort" in Sanskrit. Idā has a moonlike nature and female energy with a cooling effect. It courses from the right testicle to the left nostril and corresponds to the Ganges river. Ida nadi controls all the mental processes while Pingala nadi controls all the vital processes.
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