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The skin of the hands and feet suddenly becomes thick, rough, and round and short like a callus; this is called *piandi* (callus). This occurs because blood and qi circulate sluggishly and fail to nourish the exterior, causing the skin to become rough and thick. When the skin at the margins of the fingernails and toenails peels up, it is called *nizhou* (hangnail/reverse cuticle). This is due to wind pathogen invading the couli (interstices), leading to disharmony of blood and qi.

When flesh grows between the toes resembling a thorn, it is called *rouci* (fleshy spur/callus). The formation of fleshy spurs results from wearing tight or small shoes, causing the toes to rub against each other.

*Roulie* (skin fissure) refers to the skin being taut and the flesh cracking and breaking. This is caused by deficiency in the couli, allowing wind pathogen to invade and clash with blood and qi; the flesh cracks at the site of impact.

*Junlie* (chapped skin/fissure) refers to the rupture of muscle and skin. It is named so because exposure to wind and cold during cold seasons causes the skin of the hands and feet to crack.

*Shijiao* (cadaver foot/heel fissure) is the name for cracked and broken heels. This is also attributed to exposure to cold qi in winter. Another explanation states that stepping on ground where dead bodies have lain can also cause heel fissures.

*Bing* (a specific foot ailment) refers to swelling and rigid straightness from below the knee down to the ankle and toes. This is generally caused by deficiency of blood and qi, where wind pathogen injures the meridians, resulting in obstruction and stagnation. It is also said that people in various counties in Jiangdong often suffer from this disease; they claim there is a grass in that region called [Nameless Grass], and accidentally stepping on or touching it induces this condition.

*Jinluan* (tendon spasm) with inability to flex or extend refers to the tendons becoming tense, spasmodic, and contracted, preventing extension. Tendons become flaccid and relaxed when exposed to wind-heat, but become tense and contracted when exposed to wind-cold.

Pain in the four limbs without a fixed location refers to sudden pain in the joints of the fingers and toes, not confined to one spot. The painful area is not swollen, nor does the color change; rather, there is a pulling pain deep within the muscles, as if pierced by an awl or knife. This is due to bodily weakness allowing wind pathogen to invade. As wind pathogen moves with qi, when righteous qi is deficient, the pathogenic qi prevails. The clash between pathogenic qi and righteous qi generates pain at the site of deficiency, hence the pain has no fixed location.

*Genchu* (heel collapse/pain) refers to sudden pain in the heel that prevents bearing weight on the ground. The world calls this "heel collapse."

It describes a hard nodule under the sole, firm as stone, with pain akin to piercing by an awl or knife. This is caused by deficiency in the Kidney Meridian, where wind-toxic qi injures the area and clashes with blood and qi, resulting in pain and a hard, indurated mass that does not dissipate.

This occurs when there is initially a sore on the toe, and soil falls into the wound, exacerbating swelling and pain, and also inducing aversion to cold and high fever.