Hegu Cavity Joining Valley: First Dorsal Interosseous Fascial Decompression, Yangming Meridian Clearance, and Distal Upper-Limb Kinetic Vectoring in Classical Neigong
At its core, the somatic cultivation of *Hegu* involves the conscious activation, mechanical decompression, and energetic conduction of the webbed junction between the first and second metacarpal bones. In Classical Neigong, this region is referred to as the *Hu Kou* (虎口), or the "Tiger’s Mouth." When practitioners speak of "opening the Tiger’s Mouth," they refer to a precise postural dynamic: maintaining a rounded, buoyant arch between the thumb and index finger rather than allowing the thumb to collapse inward or hyperextend outward.