BL42 Soul Door

Reviewed by · Licensed Acupuncturist & TCM Physician · Last reviewed June 2026

BL42 (Pohu, “Soul Door”) is the Back-Shu of Lung point of the Bladder Meridian. It is located on the upper back, 3 cun lateral to the lower border of the spinous process of the third thoracic vertebra (T3), at the level of BL13 (Feishu). It regulates lung qi, calms the spirit, strengthens the back.

Location

On the upper back, 3 cun lateral to the lower border of the spinous process of the third thoracic vertebra (T3), at the level of BL13 (Feishu).

Needling

Oblique insertion 0.5-1.0 cun. Caution for pneumothorax.

⚠ Pneumothorax risk: oblique/shallow only, never deep perpendicular over the chest wall.

TCM functions

Regulates lung qi, calms the spirit, strengthens the back.

Indications

Pulmonary tuberculosis, cough, asthma, stiffness and pain of the neck and back.

Back-Shu of Lung

Clinical notes

As the Back-Shu point of the Lung, Pohu is crucial for regulating Lung Qi, addressing respiratory issues like cough, asthma, and shortness of breath, especially when related to deficiency. It also has a profound effect on calming the spirit, making it useful for emotional imbalances like grief or sadness associated with Lung disharmony. Clinically, it is often used to strengthen the back and support the Lung's energetic function.

On the Bladder channel

BL42 is one of 67 points on the Bladder Meridian. Nearby points:

Frequently asked questions

Where is BL42 located?

BL42 (Pohu) is located on the upper back, 3 cun lateral to the lower border of the spinous process of the third thoracic vertebra (T3), at the level of BL13 (Feishu).

What is BL42 used for?

BL42 regulates lung qi, calms the spirit, strengthens the back. Common clinical indications include pulmonary tuberculosis, cough, asthma, stiffness and pain of the neck and back.

How is BL42 needled?

Oblique insertion 0.5-1.0 cun. Caution for pneumothorax. Caution: ⚠ Pneumothorax risk: oblique/shallow only, never deep perpendicular over the chest wall.

Which meridian is BL42 on?

BL42 is a point on the Bladder Meridian (Zú Tài Yáng Páng Guāng Jīng).

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⚠️ This page is for general education and is not medical advice. Acupuncture is a traditional practice; evidence varies by condition and study quality, and individual results differ. It does not replace diagnosis or treatment by a licensed professional. Always consult a qualified acupuncturist or physician.