Sanjian (Third Space), or Large Intestine 3 (L.I-3), is a hand pressure point commonly used to relieve sore throat, toothache, eye discomfort, and facial paralysis. Located just behind the knuckle on the radial side of the index finger, L.I-3 plays an essential role in clearing heat, regulating facial function, and restoring energetic balance in Traditional Chinese Medicine (TCM).
This point is part of the large intestine meridian and is often stimulated in treatments involving the throat, oral cavity, and face. In modern anatomical acupressure systems, it is also occasionally referred to simply as “LI3” or “Third Space.”
Summary Table
| Attribute | Details |
|---|---|
| Pressure Point Name | Sanjian – L.I-3 (Third Space) |
| Body Area | Hand |
| Exact Location | On the radial (thumb) side of the index finger, just behind the knuckle at the metacarpophalangeal joint, at the border of the red and white skin |
| Common Uses | Toothache, sore throat, facial pain, eye problems, hand stiffness |
| Stimulation Technique | Press with moderate pressure behind the knuckle while making a loose fist, for 1–2 minutes |
| Contraindications | Avoid during pregnancy unless under professional guidance |
Clinical Significance & Associated Conditions
Sanjian (L.I-3) is indicated in both clinical and self-care contexts for conditions involving the face, mouth, throat, and hands. TCM texts describe its primary function as dispersing wind and clearing internal heat, especially in the Yangming channel, which traverses the face. Modern applications of this point include relief for:
- Acute or chronic toothaches
- Sore throat, pharyngitis, or tonsillitis
- Mild eye inflammation or redness
- Facial paralysis and Bell’s palsy
- Pain and stiffness in the index finger and hand joints
The point also acts on energetic flow in the large intestine meridian, which influences the immune system and local inflammation response.
Location
L.I-3 is found on the radial side of the index finger, in the depression just proximal to the metacarpophalangeal joint. To locate it:
- Make a loose fist.
- Observe the thumb side of the index finger.
- Find the small dip just behind the knuckle (toward the wrist) on the edge where the skin transitions in tone (red to white).
Apply firm yet comfortable pressure directly in this hollow.
Looking for an easier way to use this point in your wellness routine?
This pressure point is simple to locate and even easier to apply when guided step-by-step. It’s featured in over 70 evidence-based pressure point protocols inside our Pressure Points Guide app. Whether you’re looking to relieve sore throat, ease facial tension, or improve hand mobility, the app guides you through every session with visuals and audio. Click here to download our app.
How to Stimulate It
- Tool: Use your thumb or the knuckle of your opposite hand.
- Pressure: Moderate, steady pressure — enough to feel a slight ache but not pain.
- Duration: 1 to 2 minutes per session.
- Frequency: Up to 3 times daily as needed, especially during symptom flare-ups.
- Position: Can be done seated, standing, or during a breathing meditation.
Often paired with L.I-4 (Hegu) for enhanced anti-inflammatory and analgesic effects when treating head and throat conditions.
Benefits and Common Uses
Physical Benefits
- Relieves throat inflammation and soreness
- Eases dental pain, especially in upper molars
- Reduces swelling or pain in the hands and fingers
- Supports recovery from facial paralysis
- Calms minor eye discomfort
Energetic and TCM Benefits
- Clears wind-heat and pathogenic factors in the upper body
- Regulates qi and blood flow in the face and hand meridians
- Facilitates yangming channel circulation
Physiological Functions & Mechanisms
L.I-3 influences both local nerve branches in the hand and remote regions via meridian pathways. From a TCM perspective, stimulating this point promotes the dispersal of excess heat and stagnation, especially in areas governed by the Large Intestine channel. It is often included in protocols that aim to modulate immune response, reduce inflammation, and support facial nerve rehabilitation.
Practitioner Insight
When working with clients experiencing tooth pain or post-dental surgery discomfort, I often combine L.I-3 with points like L.I-4 and ST-6. The localized pressure behind the index knuckle provides surprisingly fast relief. I’ve also found it particularly useful for musicians or artists with hand fatigue — it restores dexterity without overloading the hand.
Safety & Contraindications
- Avoid during pregnancy due to its proximity to points that stimulate uterine contractions.
- Do not use on broken skin, open wounds, or areas with infection.
- If symptoms persist beyond 5–7 days of treatment, consult a medical provider.
For full guidance on proper technique and risks, see our Acupressure Safety Guide and explore more insights at our Acupressure category.
As always, listen to your body and stop if discomfort arises.
Related Points & Techniques
- L.I-4 (Hegu) — synergistic with L.I-3 for mouth and sinus conditions
- ST-6 (Jiache) — helpful for jaw tension and facial pain
- B 10 (Heavenly Pillar) — relieves neck tension contributing to head symptoms
- Adjunct methods: Try breathwork, warm compresses, or gentle tapping on the area
More sessions with Sanjian (Third Space) (L.I-3) in our Pressure Points Guide App
Scientific Perspective
Although L.I-3 is less studied in isolation, its associated meridian has shown responsiveness in studies evaluating electroacupuncture and manual pressure for facial pain and inflammatory conditions. According to NIH-backed research, acupoint stimulation along the Large Intestine meridian modulates sensory input and neuroimmune interactions — potentially influencing cytokine expression and endorphin release. Continued clinical research supports its role in oral-facial symptom management and hand rehabilitation strategies.