Which type of Qi circulates on the exterior of the body?

The type of Qi that circulates on the exterior of the body is Jin. In Traditional Chinese Medicine, Jin Qi is often understood as the corporeal or functional aspect of Qi that nourishes the skin and muscles, maintaining the protective barrier of the body against external pathogens. This type of Qi plays a crucial role in the overall defense mechanism and is closely associated with the body's surface layer, where it is involved in functions such as thermoregulation and resilience against environmental influences.

The other options refer to different forms or aspects of Qi with specific roles. Ye Qi, for example, pertains to the more subtle, fluid aspect of Qi, often associated with the body’s deeper systems and fluids. Yuan Qi represents the source or original Qi, which is foundational and resides more within the body’s deeper reservoirs. Shen, on the other hand, is related to the mind and spirit, reflecting consciousness and emotional health rather than physical protection. By understanding that Jin circulates on the exterior and serves protective functions, one can appreciate its significance in maintaining health and defending against external challenges.