A support mechanism may maintain a middle phalanx in a fixed position relative to an imaging sensor/receptor during a bone mineral density (BMD) test. The mechanism may comprise a flat hand plate and a cover. The cover may be shaped so that it guides the finger towards the target area of the receptor. The cover may be raised slightly above the hand plate. A hand may be placed in the mechanism with the palm facing downwards, resting on the hand plate, and the middle finger raised and resting flat on an imaging receptor. A musculoskeletal response may ensure that the middle phalanx remains proximate the imaging receptor for the duration of the BMD Test.