On the posterior aspect of the leg, in the depression formed below the bellies of the gastrocnemius muscle when the muscle is flexed (approximately 8 cun inferior to BL-40).
🧭 How to find it (practical)
1. In ventral decubitus, with the leg extended and the ankle in plantar flexion, locate the point below the apex of the inverted "V"-shaped depression formed by the heads of the gastrocnemius muscle.
2. Standing on tiptoe, locate the point below the apex of the inverted "V"-shaped depression formed by the heads of the gastrocnemius muscle.
🔬 Anatomy
Junction of the gastrocnemius with the Achilles tendon, overlying the soleus muscle. Innervated by the tibial nerve.
💉 Needling
Perpendicular insertion, 1.0–1.5 cun.
📜 Etymology
Cheng (承), to support; Shan (山), mountain. The two bulges of the gastrocnemius muscle are like prominent mountains. This point lies below them, as the support of the mountains.
