The vessel originates in the lower abdomen, surfaces between the coccyx and the anus, then rises along the posterior midline following the spine. It crosses the lumbar, thoracic and cervical regions, enters the skull at the nape and reaches the brain. It continues over the vertex, descends the forehead and nose, and ends at the frenulum of the upper lip, where it meets the Conception Vessel.
The Du Mai is the sea of the Yang meridians: it governs and warms all the Yang of the body. Its pathway along the spine gives it a central role in spinal stiffness and pain, from the lower back to the neck. Its relationship with the brain and marrow explains its use in memory disorders, dizziness, epilepsy and loss of consciousness. Its highest points, at the vertex, are used to raise collapsed Yang and clear the mind.