The thickness of the arm generally does not have any relationship with the passage or non-passage of the meridians, while the arm if there is pain, discomfort and other symptoms, only with the meridians have a direct relationship with the passage or non-passage of the meridians. The human body meridians are very smooth, once the meridians appeared in the state of stagnation of qi and blood stasis, there will be obvious pain, swelling, and even the symptoms of restricted movement. The main determinants of arm thickness are the arm muscles, fat, and genes inherited from parents. People who exercise regularly, especially doing strength training for the upper limbs, will significantly increase the circumference of their arms. And people who don’t exercise regularly and people who are thin and weak generally don’t have arms on the thick side. Most of them belong to the obese people, only to appear the phenomenon of arm thickening, these are not related to the meridians.