Subtle channels (Skt. nāḍi; Tib. tsa; Wyl. rtsa) — There are 72,000 subtle channels in the body, but the three principal ones are:
- the central channel (Skt. avadhūtī; Tib. uma; Wyl. dbu ma), running parallel to the spine,
- the right channel (Skt. rasanā; Tib. roma; Wyl. ro ma) and
- the left channel (Skt. lalanā; Tib. kyangma; Wyl. rkyang ma), which run either side of the central channel.
The right and left channels coil around the central one at a number of points to form a series of "knots". Along the central channel are situated a number of “channel wheels,” the chakras or energy-centers, from which channels branch off like the ribs of an umbrella.
- Energy channels