The reasons for not being able to measure blood pressure in the right arm can be categorized into measurement method factors, blood pressure meter factors and physical factors. 1. Measuring method factor: the stethoscope’s body part is not placed in the position of brachial artery during measurement, so the sound of arterial pulsation cannot be heard and the blood pressure cannot be measured. 2. Blood pressure meter factors: mercury column sphygmomanometer is damaged, there may be mercury column damage, cuff leakage and other problems, electronic sphygmomanometer airbag leakage, sensor dysfunction, inflatable pump damage, etc., replacement of the sphygmomanometer can measure the blood pressure. 3. Physical factors: right arm vascular diseases such as aortic obstruction, aortitis, etc., can be clarified by vascular ultrasound and other examinations. When the right arm can not measure the blood pressure, you can compare the measurement of bilateral blood pressure, such as the other side can not be measured need to rule out equipment failure and measurement method problems, such as the other side can be measured in time to seek medical treatment to avoid delaying the treatment of the disease.