A caliper is arranged for applying predetermined constant pressure to a joint or other anatomy under measurement. The caliper includes an elongate housing, a first jaw connected to the housing, a second jaw slidably connected to the housing, the first and second jaws spaced apart by a predetermined minimum distance, and a constant force spring engaging the first and second jaws. The constant force spring biases the first and second jaws toward one another. A method includes using the caliper to measure anatomical dimensions.
