In both the Western and Eastern Mystery traditions the vital energy polarities of the human nervous system are often symbolized by two snakes intertwined. These subtle energy channels are called the Nadi in Sanskrit and Od and Obd in Hebrew.
According to Kundalini yoga, the Nadis can be thought of as energetic channels (not an anatomical structures). They are the plus and minus circuits of our bodies subtle electrical system.
These two polarities Ida and Pingala (Od and Obd) intertwine around the spinal column or the Sushumna nadi (the middle pillar in Qabalah).
They are symbolized in the western mystery tradition by the Caduceus of Hermes.
“the two snakes of which symbolize the kundalini or serpent-fire which is presently to be set in motion along those channels, while the wings typify the power of conscious flight through higher planes which the development of that fire confers”.
C. W. Leadbeater, Chakras, Adyar, 1929