High risk of pneumothorax. Do not needle perpendicularly or deeply.
📍 Location (classical)
On the upper back, 3 cun lateral to the inferior border of the spinous process of the sixth thoracic vertebra (T6), at the level of BL-16.
🧭 How to find it (practical)
Seated with the head flexed, locate the point below the spinous process of the sixth thoracic vertebra, 3 cun lateral to Ling Tai (GV-10).
🔬 Anatomy
Trapezius, latissimus dorsi, and rhomboid major muscles.
💉 Needling
Oblique insertion toward the spine, 0.3–0.5 cun.
📜 Etymology
Yi Xi (譩譆), the sound of a sigh. At the moment of inserting the needle at this point, in antiquity the patient was asked to pronounce the sound Yi Xi — hence "the sound of a sigh."
