Si Zhen: The Four Examinations (四診)
Si Zhen (四診, Four Examinations) is the complete diagnostic methodology of Chinese Medicine. The four pillars — Observation (望診), Listening/Smelling (聞診), Inquiry (問診), and Palpation/Pulse (切診) — together provide the practitioner with a multidimensional picture of the patient's condition.
1. Wang Zhen (望診) — Observation
Visual inspection of complexion color, tongue body and coating, eyes and spirit (神), posture and movement, nails, hair, and skin. Key diagnostic signs: Red complexion = Heat; Pale = Cold/Deficiency; Yellow = Dampness/Liver; Blue-green = Pain/Stagnation; Dark = Kidney deficiency. Tongue body red = Heat; pale = Cold; purple = Blood stasis. Thick white coating = Dampness; yellow coating = Heat.
2. Wen Zhen (聞診) — Listening and Smelling
Listening to voice quality (strong = Excess, weak = Deficiency), breathing patterns, and digestive sounds. Smelling body odors: rancid = Liver; scorched = Heart; fragrant-sweet = Spleen; fishy = Lung; putrid = Kidney.
3. Wen Zhen (問診) — Inquiry
Systematic questioning based on the 'Ten Questions' (十問): (1) Cold-heat patterns; (2) Sweating; (3) Head and body; (4) Stools and urination; (5) Diet and appetite; (6) Chest and abdomen; (7) Hearing and vision; (8) Thirst; (9) Menstruation (women); (10) Sleep quality. Each answer localizes the pattern within the Eight Principles framework.
4. Qie Zhen (切診) — Pulse and Palpation
Pulse diagnosis at the radial artery using three positions (Cun 寸, Guan 關, Chi 尺) on each wrist, totaling six organ positions. The 28 classical pulse types provide nuanced pattern information: Floating (浮) = Exterior; Deep (沉) = Interior; Rapid (數) = Heat; Slow (遲) = Cold; Wiry (弦) = Liver/Pain; Slippery (滑) = Phlegm/Pregnancy; Thin (細) = Blood deficiency; Big (洪) = Heat/Excess.