As to the angle of insertion, the needle is usually inserted obliquely toward the spine or horizontally from the upper to the lower. It is inadvisable to puncture perpendicularly or obliquely and laterally. The depth of insertion is 0.5 - 0.8 cun. Deep insertion may puncture the pleural cavity and cause pneumatothorax.
Jianjing (GB 21)--It is needled perpendicularly about 0.5 cun. Deep insertion may impair the internal organs.