Abstract: Apparatus for measuring a volume change for facial swelling of a person which may occur after surgical removal of wisdom teeth, including a bite fork engageable within the mouth of the person for providing a relatively fixed reference position for the facial swelling; a reciprocable feeler rod having a free end with a feeler wheel secured thereto and reciprocable in a first x-axis direction substantially normal to the facial swelling; a spring which biases the feeler wheel into contact with the facial swelling; a tracing device for moving the feeler wheel in a second y-axis direction substantially normal to the first direction to cause the feeler wheel to trace across the facial swelling in a plurality of parallel planes spaced apart by a predetermined distance in the z-axis direction; a first LVDT for producing a first signal in response to the reciprocable movement of the feeler wheel in the first direction; a second LVDT for producing a second signal in response to movement of the feeler wheel in the secon