Chinese: 譩譆
Pinyin: Yī Xī
3 cun (about 4 finger-breadths) lateral to the lower border of the spinous process of the 6th thoracic vertebra (T6).
First locate the spinous process of the 7th cervical vertebra (C7), which is still palpable when the neck is being flexed and extended, while the 6th cervical vertebra (C6) starts to slide anteriorly and gradually disappears.
The spinous process of the 6th thoracic vertebra (T6) is six spinous process below C7.
Or locate the spinous process of T7, which is level with the inferior angle of the scapula, when the patient is seated with their arms hanging down. T6 is one thoracic vertebra above.
Yixi BL-45 is 3 cun lateral to the lower border of T6. Dushu BL-16 is at the same level but 1.5 cun lateral to T6.
Points located between Fufen BL-41 and Zhibian BL-54 are in the lateral branch of the Bladder Channel, while these between Fengmen BL-12 and Baihuanshu BL-30 are in the medial branch.
Obliquely 0.3–0.8 cun.
Caution: Pneumothorax.
Yixi BL-45 is at the same level as Dushu BL-16, which is the Back Transporting-Shu point of the Governing Vessel.
Both points share some similar actions and indicated for disharmony of the Vessel.