Brahma Nadi is the spinal channel as per Yoga. There are 72,000 such nadis present in the human body. Out of them, 14 nadis are said to be more important. The most important nadi is called Sushumna. It goes from the muladhara energy center at the base of the body up to the head. In modern physiology it is called the spinal cord. Inside it is the spinal canal, which is called brahma nadi. It is also known as Brahma dwara and is mentioned in Shat-chkranirupana - 3 and Hathayogapradipika – II:65. The name because kundalini power which remains dormant in all of us, when aroused, rises up through the brahma nadi, piercing through the six chakras situated on the way, ultimately merges into Shiva, located inside of the brain. Their union results in the realization of Brahman, the basic reality underlying life. Therefore, this nadi, is called the Brahma nadi.
The Brahma nadi is said to be surrounded by two other nadis, namely chitrini and vajra. These three nadis are located inside the vertebral column.
Outside the spine there are two important nadis. They are ida or Chandra nadi, located on the left side of the sushumna (which goes to the left nostril), and pingala situated on the right side going to the right nostril. By a prolonged practice of pranayama, the two outer nadis, ida and pingala, stop the flow of vayus. The central nadi then opens up, leading to prana to Brahman.