From an acupuncture perspective, downward-facing dog has gained its rightful place at the top of the yoga-pose heap because it activates the "Bladder Channel."
The Bladder channel, sometimes referred to as tai yang, is the longest channel in the body. It has 67 acupuncture points that run from the inner eye, up and over the head, down the entire spine and posterior leg, along the side of the food and ending at the pinkie toe.
