In general, very little is said or explained with regard to these Nadis. Moreover, they may even be a nickname or synonym, or perhaps an extension or branch of one of the fourteen major Nadis.
Mind that we don’t discuss Vajra Nadi, Chitrini Nadi, and Brahma Nadi in this post, which are the well described “inner Nadis” of Sushumna Nadi. To learn more about those, you may read our post Inside Sushumna – Vajra, Chitrini, and Brahma Nadi.
At any rate, here further below we then briefly discuss the “lesser Nadis.” You’ll find them mentioned in alphabetical order.
Kurma Nadi is talked about in several texts, and is thought to be located in the throat or chest region. The word “Kurma” means “tortoise.”
According to the descriptions of this channel, the Nadi seems to serve some kind of mental or cognitive improvement or strength.
“Below the cavity of the throat, there is a beautiful Nadi (vessel) called Kurma; when the Yogi fixes his attention on it, he acquires great concentration of the thinking principle (Chitta).” (Shiva Samhita).
And another example: “Focusing with perfect discipline on Kurma, the ‘tortoise channel’, one cultivates steadiness.” (Yoga Sutras of Patanjali).
As stated in the Yoga Shikha Upanishad: “Raka Nadi quickly consumes water and produce sneezing and phlegm in the nose.”
The above may suggest an association with the esophagus or pharynx.
Shubha Nadi is mentioned in the Tri Sikhi Upanishad. There it’s written: “The Shubha Nadi stretches up to the tip of the genitals.”
Shura Nadi is also known as Sura Nadi. It’s only mentioned in the Yoga Shikha Upanishad as follows:
“Pusa and Alambusa go to the ears. Therefrom the great Nadi Sura proceeds to the middle of the eyebrows.”
It’s unclear if Sura Nadi starts in the Kanda, or is rather an extension or branch from another Nadi.
Vilambini Nadi, also called Wilambini Nadi, is mentioned in the Yoga Shikha Upanishad.
In the text it’s stated that: “Vilambini is peculiarly placed in the navel which is the junction of Nadis originating and going upwards, downwards and cross-wise, making the navel chakra like the egg of the hen.”
Another remark in the Yoga Shikha Upanishad goes like this: “On either side of it [Sushumna], Nadis Ida and Pingala are located. Vilambini is interwoven in between till it reaches the nostrils.”