“Tong” means to pass or go through. “Gu”, meaning a valley, refers to a depression. It is the Ying-spring point of the Urinary Bladder Meridian of Foot-Taiyang, so the qi of the meridian passes quickly through it. Hence the name Zutonggu (Passing Valley).
In the depression anteroinferior to the 5th metatarsophalangeal joint, at the junction of the white and red skin.
- Neck rigidity.
- Blurring of vision.