On the posterior aspect of the leg, midway between BL-55 and BL-57, at the center of the belly of the gastrocnemius muscle.
🧭 How to find it (practical)
Seated with the ankle in plantar flexion or in horizontal ventral decubitus, locate the point at the center of the bulge of the gastrocnemius muscle, between Wei Zhong (BL-40) and Cheng Shan (BL-57).
🔬 Anatomy
Gastrocnemius and soleus muscles. Innervated by the tibial nerve.
💉 Needling
Perpendicular insertion, 1.0–1.5 cun.
📜 Etymology
Cheng (承), to support; Jin (筋), tendon. Cheng Jin refers to the gastrocnemius muscle. The point lies over this important muscle of the lower limb, which supports the weight of the body.
