While Ida and Pingala are engaged directly through nadi shodhana, alternate nostril breathing, Sushumna is described in yogic and tantric texts as normally closed, its opening the goal rather than the immediate object of most breath practice. Preliminary work in Ida and Pingala is held to prepare the way for prana to enter Sushumna, at which point deeper meditative absorption is said to become possible, since Sushumna is the channel through which awakened energy is described as rising toward the crown.
Along Sushumna's length the tradition places a series of granthis, psychic knots, at the base of the spine, the heart and the point between the eyebrows, marking where Ida and Pingala are said to cross the central channel, and texts describe these as points of resistance that rising energy must loosen in turn.
Sushumna is sometimes likened to the Governing Vessel of Chinese medicine, another channel running along the spine, but the two belong to separate traditions with independently developed anatomies, and the resemblance in position does not make one a translation of the other; each system's own texts describe a distinct set of channels, functions and practices that developed without reference to the other.