Insert obliquely by 0.5 to 1 cun in a cranial (approximately 45°) and lateral direction towards the coracoid process.
Caution: deep perpendicular or oblique insertion carries a substantial risk of causing a pneumothorax.
This point is mostly used to clear Excess of all kinds from the Lungs, whether due to Exterior pathogenic factors (e.g. Wind-Cold or Wind-Heat) which penetrate in the Lungs, or to internally generated disharmonies (e.g. Phlegm-Heat, Qi Stagnation, etc.).
In particular, it is very well indicated for cough caused by retention of Phlegm in the Lungs.
The point isn't normally used when the invasion is still on the Exterior but, since it has a good effect on stopping cough, it can be used in the early stages of invasion if cough is a prominent symptom. In that case it's used in conjunction with points that release the Exterior.