Thumb part of the crescent moon becomes smaller to consider and immunity to reduce, the lack of micronutrients have a direct relationship, the part is called nail half moon, and the quality of the body directly related to the local hospital is recommended to carry out micronutrient testing. If you find that there is a lack of trace elements, targeted supplementation can be, if the trace elements are normal should be considered from the immune system, the recent emergence of poor rest, lack of sleep, mental stress and other symptoms may occur, it is recommended to adjust the work and rest routine, to maintain an optimistic and cheerful mood, and increase their own sports in moderation. If the half-moon on the nail appears to be sunken or broken, you need to go to the local hospital for a fungus test to rule out nail fungus disease.