Bladder Meridian
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BL-21
Safety Warnings
- Dangerous point - requires extra caution
- Deep needling contraindicated - shallow insertion only
Needle Depth
0.5–0.8 cun
Needle Angle
45° (Oblique), 10-15° (Transverse)
Body Area
Back — Upper (Thoracic)
Location
1.5 cun lateral to the lower border of the spinous process of the 12th thoracic vertebra (T12).
Main Actions
- Tonifies Stomach Qi
- Subdues Rebellious Stomach Qi
- Resolves Dampness
Indications
Commentary
As the Back Transporting-Shu point of the Stomach, Weishu BL-21 is an important point with various functions related to the Stomach.
First of all, it strongly tonifies the Stomach Qi. Thus it can ease poor appetite, fatigue, weak limbs and thin body without strength. It often used together with Pishu BL-20 to tonifies the Spleen and the Stomach. Both Organs are the Root of the Post-Heaven Qi, Blood and Food Essences. The combination of these two points helps patient who suffer from long-term physical and mental exhaustion or simply low in energy.
Secondly, with Reducing Needling method, it also regulates Stomach Qi and subdues Rebellious Qi, characterized by symptoms such as belching, hiccup, nausea and vomiting. It also relieves food retention in the Stomach, causing epigastric fullness or sour regurgitation.
Finally, it resolves Dampness as well as it tonifies the Spleen Qi to some extend.
Classical Sources
Zhenjiu Jiayijing (針灸甲乙經 - Systematic Classic of Acupuncture and Moxibustion): "Stomach cold with distension, excessive eating with thin and weak body, abdominal fullness with rumbling."
Zhenjiu Dacheng (針灸大成 - Great Compendium of Acupuncture and Moxibustion): "Treats cholera-like disorder, cold Stomach, abdominal distension with rumbling, vomiting with food reversal, poor appetite, excessive eating with thin body, dim eyes, abdominal pain, and chest and hypochondrium fullness."
Leijing Tuyi (類經圖翼 - Illustrated Supplement to the Classified Canon): "For children who are thin with poor appetite."
How to Locate
First 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. T12 is five thoracic vertebra below. Or identify the Tuffier's line which connects the highest points of the iliac crest. The spinous process of the 4th lumber vertebra (L4) mostly falls on this line. Then identify the spinous process of T12 by counting four up. Weishu BL-21 is 1.5 cun lateral to the lower border of T12. Weicang BL-50 is at the same level but 3 cun lateral to T12. 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.
Caution
Located over the thoracic region with risk of pneumothorax if needled perpendicular or too deeply. Always use oblique insertion toward the spine or transverse insertion. Perpendicular needling is contraindicated. Ensure patient is in a comfortable position (prone or lateral) and avoid any sudden movements during needling.
Needle Angle
45° (Oblique) / 10-15° (Transverse)
Depth Category
Shallow
Standard Depth
0.5–0.8 cun
Needling Directions
0.5–1 cun obliquely towards the spine. Or 1 to 1.5 cun transversely towards the spine. This method applied more often as it allows the patients to lie in a supine position easily during needling retention. Caution: Pneumothorax.
Expected Deqi Sensation
Local distension and soreness spreading across the mid-back region. Deqi sensation may radiate toward the spine or around the lateral costal region. Some patients experience a referral sensation toward the epigastric area, reflecting the point's connection to the Stomach organ.
Moxibustion
Particularly Recommended
Duration: 10–15 minutes
Cupping
Recommended
Bloodletting
N/A
Gua Sha
Recommended
Organ & Tissue Associations
Back-Shu Point for:
Stomach
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