The Directing Vessel starts from the lower abdomen, then travels upward from below along the interior of the spine, enters the brain, and finally stops at the upper lacrimal girdle. The Directing Vessel starts from the abdomen, passes through the perineum, reaches the end of the tailbone, then travels upward in the spinal column, reaches the Fengfu point in the neck, enters the brain, continues upward to the top of the head, travels downward along the forehead to the nasal column, and finally stops at the upper lip lacing. The Directing Vessel can regulate Yang meridian qi and blood, and is the “Sea of Yang Vessel”; because it travels up the spine, enters the brain, and passes through the heart, its physiology and pathology are closely related to the brain, the medulla oblongata, and the heart, and it can reflect the functions of the brain, the medulla oblongata, and the kidneys.