Measured demi-armspan for calculating height Please enter the measured demi-armpan in cm. Measuring demi-armspan in a recumbent patient. Measure the distance from the middle of the sternal notch (v-at the base of the neck) to web-root between the middle and ring fingers (not the finger tips). Right arm preferred. Check that the patient's arm is horizontal and in line with the shoulders when extended. Bassey EJ. Demi-span as a measure of skeletal size. Annals Hum Biol 1986;13:499–502. Close