A vital sign measurement device includes a sensor fixation device, an optical sensing system, and an output unit. The sensor fixation device is adapted to be placed against an anatomical location of a subject, within which is an artery. The optical sensing system includes an optical source, an optical refractor, and an optical detector, all of which are held by the sensor fixation device and move with movement of the sensor fixation device. The optical sensing system is positioned with respect to the sensor fixation device to sense movement corresponding to an arterial pulse when the sensor fixation device is placed against the anatomical location of the subject. The optical sensing system can sense an arterial pulse from the movement, bending, or compression of at least one portion of the optical sensing system relative to other portions of the optical sensing system resulting in a change in an optical signal received by the optical detector. The output unit receives, from the optical sensing system, an input indicative of movement corresponding to an arterial pulse and generates, using the input, a measure of the vital sign.