Introduction: Clinical Application of "For diseases in the upper part, treat the lower part; for diseases in the lower part, treat the upper part; for diseases in the head, treat the feet; for diseases in the waist, treat the popliteal fossa."

"For diseases in the upper part, treat the lower part; for diseases in the lower part, treat the upper part; for diseases in the head, treat the feet; for diseases in the waist, treat the popliteal fossa." This classic text is from the "Lingshu·Zhongshi" chapter.

This means that when a disease manifests in the upper part of the body, acupoints located in the lower part can be selected for treatment; conversely, when a disease manifests in the lower part, acupoints distributed in the upper part can be selected for treatment.

For conditions affecting the head, acupoints on the feet can be chosen for treatment; for issues in the waist, acupoints in the popliteal fossa (such as Weizhong) can be selected.

This method of selecting acupoints falls under distal point selection in acupuncture, also known as meridian-based point selection, and is an important fundamental principle in acupuncture prescription.

The theoretical basis for this point selection principle is the meridian theory.

Because the meridians are distributed throughout the body—upper and lower, internal and external—connecting the internal organs and linking the limbs and joints, they serve as pathways for the circulation of nutrient qi, defensive qi, blood, and vital energy. The disruption or blockage of qi and blood in the meridians is often a significant factor in the occurrence of diseases.

Therefore, the method of selecting distal points along the meridians is based on the distribution characteristics of the meridians and their function of circulating qi and blood, combined with fundamental theories such as the root and branch, as well as the root and tip of the meridians.

In terms of the theories of the root and branch, as well as the root and tip of the meridians, they primarily elucidate the interconnectedness, concentration, and diffusion of meridian qi, demonstrating corresponding relationships between the upper and lower, as well as the internal and external parts of the body.

The root and branch, as well as the root and tip of the meridians, exhibit corresponding characteristics: the root and the base are distributed at the extremities of the limbs, while the tip and the knot are distributed in the head, face, and trunk.

The head, face, abdomen, and back are located above, while the extremities are below. The therapeutic effects of acupoints in these upper and lower regions influence each other, providing a theoretical basis for the method of selecting distal points along the meridians.

Thus, the method of selecting acupoints is proposed: treating upper body disorders by selecting points in the lower body, treating lower body disorders by selecting points in the upper body, treating head disorders by selecting points on the feet, and treating lumbar disorders by selecting points in the popliteal fossa.

For example, the *Zhenjiu Juying·Zhou Hou Ge* states, "For disorders of the head and face, needle Zhiyin (BL67); for disorders of the legs and feet, seek Fengfu (GV16)." Similarly, the *Si Zong Xue Ge* states, "For abdominal disorders, retain Zusanli (ST36); for lumbar and back disorders, seek Weizhong (BL40); for head and neck disorders, seek Lieque (LU7); for facial and oral disorders, retain Hegu (LI4)." These commonly used acupoint selection methods are specific clinical applications of this principle.

The method of selecting distal points along the meridians is widely applied in clinical practice. However, when applying it, it is essential to consider both the distribution and pathways of the meridians, as reflected in the principle "where the meridian passes, it governs," as well as the interrelationships between the roots, knots, and branches of the meridians. At the same time, a comprehensive analysis should be conducted based on the fundamental theories of Traditional Chinese Medicine. Only then can appropriate acupoints be selected for treatment, ensuring skillful point selection, a well-founded approach, and significant therapeutic efficacy.

For example:

Pain in the inner canthus of the eye, mild during the day and severe at night, accompanied by insomnia and excessive dreaming, indicates a syndrome of yin deficiency and yang hyperactivity, where deficient fire ascends along the meridians to the head and face, representing a condition of root deficiency and branch excess.

In clinical practice, the "Zhaohai" (KI 6) point of the Foot Shaoyin Kidney Meridian can be selected for treatment. Since the Zhaohai point is the starting point of the Yin Heel Vessel, and the inner canthus is the convergence point of the Yin and Yang Heel Vessels, selecting Zhaohai exemplifies the method of treating upper body disorders by needling lower body points.

Another example:

For lower limb flaccidity and numbness, treat at the Fengfu (GV 16) point.

Because the Fengfu point is the meeting point of the Governor Vessel, Foot Taiyang, and Yang Linker Vessels, as recorded in the "Thousand Ducat Formulas": "For numbness of the feet, Fengfu and Yaoshu govern it." This is just as the "Elbow-Back Song" states: "For diseases of the legs and feet, seek Fengfu." This exemplifies the method of treating lower body disorders by selecting upper body points.