What measure is noted for the distance from the medial end of the eyebrow to the outer canthus in relation to TaiYang?

The correct distance from the medial end of the eyebrow to the outer canthus as it relates to the location of the TaiYang point is indeed 3 cun. This measurement is significant in Traditional Chinese Medicine (TCM) for accurately locating various acupuncture points.

The term "cun" refers to a specific unit of measurement in TCM, typically based on the practitioner's own anatomical dimensions. When considering the face, the size of the "cun" value can be effectively applied to the distance between facial features. Knowing that the TaiYang point is situated at the temple, the ratio of 3 cun from the medial end of the eyebrow to the outer canthus accurately reflects the established anatomical guidelines for point localization.

Measurements of 1, 2, and 4 cun do not correspond to the established anatomical distance for the TaiYang point, which is why they do not apply in this context. Thus, familiarity with these standardized distances is crucial for practitioners in ensuring precise and effective treatment with acupuncture.