A mobile, hand-held communication device with a display screen and a camera is programmed to perform a postural screening method. An image of a patient is acquired on the display screen having an array of pixels. A pixel to distance ratio of the displayed image is determined. A postural displacement of the patient in the displayed image is calculated using the determined ratio. A gyroscope, accelerometer and/or a level of the device is used to level the camera before capturing the image with the camera. Reference lines are overlaid on the display screen and the image to enable alignment of the image. A reference line on the display screen is used for normalizing a known distance in the aligned image to a reference distance of a known number of pixels on the screen for determining the ratio.