The arm is very thick may be caused by obesity, arm movement, arm venous return obstruction and other reasons 1. Obesity: due to unreasonable diet, lack of exercise and other reasons, will make the patient obese, excessive arm fat, the phenomenon of very thick arms. 2. Arm movement: due to frequent heavy lifting, arm fitness and other reasons, will make the arm muscle increase, the phenomenon of very thick arms. 3. Arm venous return obstruction: arm venous return obstruction will make the arm thicker and even varicose veins occur. When the patient’s arm is very thick, most of them don’t need to worry, if there are other uncomfortable symptoms, it is recommended to consult a doctor in time, diagnosed by a professional doctor, and give reasonable treatment to avoid delaying the condition.