🌿 Folk Prescriptions

The angle, direction, and depth of needle insertion refer to specific operational requirements after the fine needle penetrates beneath the skin. Correctly mastering these aspects during acupuncture is crucial for achieving needle sensation, applying tonification and drainage techniques, realizing therapeutic effects, enhancing treatment outcomes, and preventing accidental injuries. Accurate point selection is not merely about surface location but must be combined with proper angle, direction, and depth to fully activate the therapeutic potential of acupoints. Therefore, acupoints should not be viewed simply as flat points but as three-dimensional entities. Clinically, inserting the same acupoint with different angles, directions, or depths leads to variations in targeted tissues, needle sensations, and treatment outcomes. A clinician’s proficiency depends closely on their ability to properly control angle, direction, and depth. The actual choice of angle, direction, and depth depends on the site, treatment needs, and patient factors such as constitution and body shape.
1. Needle Insertion Angle: The angle refers to the angle formed between the needle shaft and the skin surface. Its size varies according to acupoint location, condition type, and technique requirements. Generally, three types exist: vertical, oblique, and transverse.
1. Vertical Insertion: The needle shaft forms a 90° angle with the skin surface, inserted perpendicularly into the acupoint. Suitable for most acupoints, especially those in areas with thick muscles.
2. Oblique Insertion: The needle shaft forms approximately a 45° angle with the skin surface, inserted at an incline. Used for shallow skin areas, regions containing vital organs, or acupoints unsuitable for deep vertical insertion—especially at joints. Also commonly used when applying certain Qi-moving or Qi-regulating techniques.
3. Transverse Insertion (also called horizontal or subcutaneous insertion): The needle shaft forms about a 15° angle with the skin surface, inserted horizontally. Ideal for thin-skinned, low-muscle areas such as the scalp, face, sternum. Techniques like transverse penetration and scalp acupuncture, as well as wrist-ankle acupuncture, employ transverse insertion.
2. Needle Direction: Refers to the orientation of the needle tip during insertion and afterward—simply called "needle direction." Direction generally follows the course of the meridian, acupoint distribution, and target tissue structure. Although related to angle—for example, facial acupoints often use transverse insertion, neck and throat acupoints use horizontal insertion, midline chest acupoints use transverse insertion, lateral chest acupoints use oblique insertion, abdominal acupoints use vertical insertion, back and waist acupoints use oblique or vertical insertion, and limb acupoints typically use vertical insertion—angle primarily depends on anatomical features, while direction is determined by therapeutic needs. For instance, regarding Jia Che (Cheek Vehicle): when treating jaw pain, cheek pain, or locked jaw, insert obliquely toward the temporal region to radiate sensation across the cheek; when treating facial paralysis or facial deviation, insert horizontally toward the mouth corner; when treating mumps, insert obliquely toward the parotid gland area; when treating toothache, insert vertically.
3. Needle Depth: Refers to how deeply the needle penetrates the skin and flesh at the acupoint. Depth should ensure a sensation of Qi arrival without injuring internal organs or tissues. In clinical practice, depth must consider multiple factors: patient age, constitution, condition severity, acupoint location, meridian depth, seasonal timing, practitioner experience, and need for Qi sensation. As stated in *Suwen·Ciyao Lun*: "Needling has varying depths, each suited to its purpose... improper depth becomes a great harm," emphasizing that depth must be appropriate. Key considerations include:
1. Age: *Lingshu·Nixun Feishou* says: "For infants and thin people, insert shallow and quickly; for robust adults and obese individuals, insert deep and leave longer." Elderly and weak individuals have depleted qi and blood; infants have delicate constitutions—neither should undergo deep insertion. Young adults with vigorous qi and blood may tolerate deeper insertion.
2. Constitution: Patients vary in body type—fat or thin, strong or weak. *Suwen·Sanbu Jiuhou Lun* states: "First assess the body’s size and shape to adjust qi deficiency or excess." Zhang Zhicong adds: "Knowing body type determines needle depth." Thus, thin or weak individuals should be treated with shallower insertion; robust individuals may tolerate deeper insertion.
3. Location: Insert shallowly for acupoints on the head, face, and back; deeper insertion acceptable for limbs and buttocks/abdominal areas.
4. Meridians: Meridians vary in depth and nature—yin or yang. Ancient texts suggest deeper insertion for deeper meridians, shallower for superficial ones; yang meridians (surface) favor shallow insertion, yin meridians (interior) favor deep insertion. As *Lingshu·Yinyang Qingzhuo* states: "For yin meridians, insert deep and leave long; for yang meridians, insert shallow and quickly." Meridians running through elbows, arms, knees, and legs are deeper—insert accordingly; those on wrists, ankles, fingers, and toes are shallower—insert shallowly.
5. Condition: *Lingshu·Weiqi Shichang* notes: "Diseases vary in depth and surface—each has its place. Mild cases require shallow insertion, severe cases deep insertion; mild cases use small doses, severe cases larger doses—adjust according to change." *Lingshu·Zhongshi* adds: "For full pulses, deep insertion to release qi; for empty pulses, shallow insertion to preserve essence and nourish the pulse, expelling pathogenic factors." This emphasizes that insertion depth must be adjusted based on diagnosis.
6. Technique: *Yixue Renmen* says: "Tonification draws qi from the defensive layer—light and shallow insertion, following the defensive qi to replenish deficiency. Drainage discards qi from the nutritive layer—deep and heavy insertion, intercepting nutritive qi to drain excess." *Nanjing* states: "Puncture the nutritive layer without harming the defensive layer; puncture the defensive layer without harming the nutritive layer"—emphasizing that depth must be carefully controlled. If deep insertion is needed but shallow applied, one fails to reach the nutritive layer and harms the defensive layer; if shallow insertion is required but deep applied, one over-punctures and damages the nutritive layer.
7. Seasonal Timing: Human physiology aligns with seasonal changes. Needling must adapt to seasons. *Suwen·Zhenyao Jingzhong Lun* says: "Spring, summer, autumn, winter each have their own rules." Depth must consider both condition and season. *Lingshu·Ben Shu* states: "In spring, select points on collateral vessels, major channels, and intermuscular spaces—deep for severe cases, shallow for mild ones; in summer, select points on channel outlets, collaterals, muscles, and skin; in autumn, select points on convergence points, following spring’s method; in winter, select points on well points and channel outlets—deep and leave long." Generally, shallow insertion in spring and summer, deep insertion in autumn and winter—based on *Nanjing*: "In spring and summer, yang energy resides above, and qi ascends—thus shallow insertion is appropriate; in autumn and winter, yang energy descends, and qi resides below—thus deep insertion is suitable." Ignoring seasonal patterns risks "great disorder," as warned in *Suwen·Sishi Ci Nixu Lun*: "All four seasons’ needling must follow the natural order. Deviating leads to chaotic qi and disease."
8. Needle Sensation: For patients with strong, fast, intense sensations of soreness, numbness, distension, or those anxious about needles, shallower insertion is preferable. For patients with delayed or weak sensations, deeper insertion is recommended. As *Zhenjiu Dacheng* puts it: "Depth and shallowness depend on sensation—stop when Qi arrives." Angle, direction, and depth are inseparable. Generally, deep insertion uses vertical insertion; shallow insertion uses oblique or transverse insertion. Especially for acupoints near the brainstem, eyes, chest, abdomen, and back, where vital organs lie nearby, precise control of angle, direction, and depth is essential to prevent accidental injury.