EX-UE3 · 经外奇穴Zhongquan zhōng quán · 中泉
Location. On the posterior aspect of the wrist, at the distal dorsal wrist crease, in the depression on the radial side of the tendon of the extensor digitorum.
Zhong means middle and quan means a spring. The point lies in the hollow at the middle of the dorsal wrist crease, and the name reads that hollow as a spring. It is a point outside the fourteen channels. Sources place it on the radial side of the extensor digitorum tendon, though they describe the landmark with small differences between them, and the older texts are less precise about it than they are about the channel points of the same region. Acupuncture literature attaches Zhongquan most often to oppression and pain in the chest, to pain in the epigastrium, and to spitting or vomiting of blood; it is also mentioned for eye pain and for a sensation of heat in the palm. These are entries in a list of attributions, not research findings: later writers repeated them, and no study has established them. This entry makes no claim of benefit.
定位。在腕后区，腕背侧远端横纹上，指伸肌腱（指总伸肌腱）桡侧的凹陷处。
「中」为中央，「泉」为泉源；本穴在腕背侧横纹中央的凹陷处，故名中泉。为十四经之外的奇穴。各家对本穴体表标志的记述互有出入，且较同区域经穴的记述为略。针灸文献述及本穴时，多归于胸闷、胸痛、胃脘痛、唾血或吐血，亦提及目痛与掌中热。此为历代作者归于一穴的记载之目，不是研究结论：后世转述者多，现代研究未证实。本条不作疗效陈述。
Classical record · not a treatment recommendation. Needling technique is a licensed practitioner's skill and is out of scope here.
The point sits on the back of the wrist, where the skin is thin and what lies under it lies close to the surface: branches of the superficial radial nerve, the dorsal venous network of the wrist, and just deep to them the extensor tendons, the carpal bones and the wrist joint itself. Needling there is an invasive procedure by a trained practitioner with a single sterile needle, and it is not a point for self-needling, for moxa, or for pressing a hard object into. The rest of this note matters more. The complaints this point is classically written against are the ones a point must never be allowed to stand in for: chest pain that is pressing, or that spreads to the jaw, the back or the arm, or that comes with sweating, nausea or breathlessness, is assessed as a possible heart attack in an emergency department and is not explained by a point on the wrist; vomiting blood, or blood passed another way, and pain in the upper abdomen that does not settle, are matters for endoscopy and examination. Anyone taking an anticoagulant, or with a bleeding disorder, immunosuppression, poorly controlled diabetes, a local infection or swelling, hardware from a wrist fracture, or who is pregnant, should speak to their own doctor before any needling here. After needling, spreading redness, fever, increasing pain, or numbness or tingling in the hand is a reason to seek care the same day.