[Location] Localized in the erect sitting position or supine position. Make the palm downwards. On the dorsal aspect of the forearm, on the line connecting SJ4 ( Yangchi ) and tip of the elbow. 3 cun above the transverse crease of the wrist between the ulna and radius. ( Fig.19 )
 
[Regional Anatomy] Skin→subcutaneous tissue→extensor digiti minimi→extensor pollicis longus→interosseous membrane of forearm. Superficial layer, the posterior antebrachial cutaneous nerve, the cephalic vein, the subordiantial ramus of the basilis vein: deep layer, the posterior antebrachial interosseous artery, vein and nerve.