SI4 (Wangu / Wrist Bone) Acupuncture Point Guide
Practitioner Guide from The Acupuncture Supply Co.
SI4 Wangu is a yuan-source point of the Small Intestine channel. This Project Lotus reference brings together surface landmarks, traditional theory and practical safety considerations for qualified practitioners.
Quick reference
| Point | SI4 — Wangu (Wrist Bone) |
|---|---|
| Channel | Small Intestine — Hand Taiyang |
| Classification | Yuan-Source |
| Region | Ulnar border of hand |
| Laterality | Bilateral |
| Location | At the little-finger edge of the hand, in the hollow between the fifth metacarpal base and the triquetrum, at the palmar–dorsal skin boundary. |
Location of SI4 Wangu
At the little-finger edge of the hand, in the hollow between the fifth metacarpal base and the triquetrum, at the palmar–dorsal skin boundary.
Landmark sequence
- Support the hand with its little-finger edge accessible.
- Trace the fifth metacarpal proximally to its base.
- Identify the adjacent triquetral region.
- Palpate the depression between the two landmarks at the skin boundary.
Where a B-cun measurement is given, use the patient’s proportional body measurement. It is not a fixed centimetre distance or a universal number of the practitioner’s finger breadths. Confirm the relevant landmarks by palpation before deciding on a technique.
Distinguishing nearby points
SI4 lies near the fifth metacarpal base. SI3 lies much farther distally, proximal to the fifth metacarpophalangeal joint.
Traditional functions
Within traditional East Asian medicine, this point is commonly described in terms of the following functions:
- Activates the channel and eases pain
- Clears Heat and reduces swelling
- Clears Damp-Heat in traditional theory
Traditional applications
Traditionally considered for ulnar hand or wrist discomfort and restricted finger movement, and for selected Small Intestine-channel presentations. The Yuan-Source classification supports its role in channel-based strategies.
These descriptions express traditional theory. They are not claims that this individual point has been proven to prevent or cure a medical condition. A symptom or channel label alone is insufficient to select a treatment.
Planning a point combination
Consider the treatment principle, local versus distal selection and the patient’s complete presentation. Related Project Lotus guides for comparison include SI3, HT5. These are educational comparison points, not a fixed prescription. Confirm the rationale, laterality and technique within accredited training.
Anatomy and essential safety
Review the fifth metacarpal base, carpal bones, local tendons and dorsal ulnar sensory branches. Previous fractures and wrist surgery can alter the palpable landmarks.
- Inspect the skin and assess local tissue, circulation and sensation. Do not needle through infected, ulcerated, inflamed or otherwise unsuitable tissue.
- Review relevant surgery, injuries, implants, bleeding risk, medication, pregnancy and previous adverse reactions.
- Use sterile single-use needles, appropriate infection control and safe sharps disposal. Obtain informed consent and document the treatment.
- Choose angle, depth and stimulation from anatomical assessment and accredited training. This guide gives no universal insertion depth. Stop and reassess unexpected sharp pain, neurological symptoms or a concerning response.
When medical assessment takes priority
Marked swelling or deformity after trauma, new sensory loss, or a hot wrist with fever requires medical assessment.
Moxibustion
Moxa is not an automatic addition. Consider the traditional pattern, local anatomy and the practitioner’s training. Where heat is appropriate, assess sensation, skin condition, ventilation and the patient’s ability to report discomfort; supervise continuously and prevent burns.
Research note
Evidence concerning an acupuncture treatment or a multi-point protocol cannot be assigned automatically to this point alone. This guide does not claim an independently established clinical effect for SI4. Traditional functions and clinical evidence should be discussed separately.
Frequently asked questions
Is this point bilateral?
Yes. The surface landmarks apply on both sides. Treatment laterality depends on assessment and the chosen clinical strategy.
Can the image replace palpation?
No. The image shows the landmark relationship schematically. Body proportions, tendon visibility and tissue depth vary, so trained examination remains essential.
Is this a self-needling guide?
No. It is an educational reference for qualified practitioners and does not replace professional training or medical assessment.
Continue exploring Project Lotus
Browse our Acupuncture Point Guides and professional acupuncture needles.
Professional note: Educational material for qualified acupuncture practitioners. Individual assessment, consent, safe technique and appropriate referral remain the practitioner’s responsibility.
References: WHO Standard Acupuncture Point Locations, updated reprint 2009 (entry SI4); CEIMEC point atlas (cross-check; WHO takes precedence where descriptions differ); Joel Penner, American Dragon: traditional point reference; NCCIH: acupuncture evidence and safety. Checked 5 October 2026.
