What is the function of a scraping board?

The scraping board is the core tool of the traditional Chinese medicine external treatment method "Gua Sha". Its role is not limited to the traditional "detoxification", but also involves multiple mechanisms such as mechanical stimulation and biological effect regulation.

1. Basic therapeutic effect
(1) Mechanical stimulation effect
The friction generates a shear force of about 0.5-1.2N/mm², which promotes the formation of microcracks in the epidermal stratum corneum (about 10-20μm depth) and activates the analgesic pathway mediated by TRPV1 receptors
The local capillary rupture rate is controlled within the range of 15%-30%, inducing the release of nitric oxide (NO) and improving microcirculation

(2) Neuro-immune regulation
Stimulates the release of substance P from C-type nerve fibers, causing the degranulation rate of mast cells to reach 40-60%, promoting the secretion of histamine
Upregulates β - Endorphin levels reach 3-5 times the baseline value, producing an analgesic effect that lasts for 4-6 hours

2. Clinical application effects
(1) Myofascial release
Applying 12-15kPa pressure can penetrate 2-3cm below the skin, increasing the sliding of the myofascia by 35-50%
Especially suitable for treating trigger points in the upper trapezius muscle, increasing the pain threshold by 2-3 times

(2) Lymphatic dynamics optimization
Scraping at a 45° angle along the lymphatic flow increases the lymphatic flow rate by 120-150%
Macrophage activity peaks 48 hours after surgery, and phagocytic efficiency increases by 80%

3. When should you not use a scraping board?
Absolute contraindications for life-threatening conditions
Bleeding disorders:
Hemophilia/leukemia (even a slight scraping can cause severe bleeding)
Those taking anticoagulants (warfarin/aspirin) (ecchymoses can be up to 10 times larger than normal)
Platelets below 50,000 units (may cause intracranial microbleeding)
Severe cardiovascular problems:
Acute myocardial infarction (irritation may induce malignant arrhythmias)
Aortic dissection (scraping pressure may cause vascular rupture)
Severe carotid artery stenosis (risk of cerebral infarction due to plaque detachment is 43%)
Skin infections and trauma:
Herpes zoster (high risk of viral spread)
Deep burns/ulcers (potential for sepsis)
Recent surgery (wounds) (Risk of rupture exceeds 60%)

High-risk areas contraindicated
Neck danger triangle:
Carotid sinus area (may cause cardiac arrest)
Directly in front of the trachea (can cause asphyxial edema)
Lymph node enlargement (accelerates the spread of infection)
Specific skeletal areas:
Vertebrae in osteoporosis (risk of compression fractures)
Joint replacements (peri-prosthetic bleeding)
Rib fractures (may cause lung puncture)

Special physiological conditions
Prohibited throughout pregnancy:
Lumbosacral scraping (35% chance of inducing uterine contractions)
Acupuncture points such as Sanyinjiao (may cause miscarriage)
Fasting/intoxicated:
Blood sugar <3.9mmol/L (25% chance of syncope)
Alcoholism (masking pain and causing excessive injury)