D test is an evaluation maneuver to hypothesize problems related to activities in daily life when a patient cannot perform because of some functional disorders. The procedure in the D test consists of three phases. In the first phase, the therapist investigates the joint motion axis during the ankle dorsal flexion of a patient. Next, the normal axis of ankle dorsal flexion is compared to the patient's actual axis. Finally, the therapist considers about factors and effects due to ankle axis abnormality, and observes and analyzes the ‘chain’ action from foot to head. The D test is very useful in the field of physical therapy evaluation. And for its clinical applications, it is necessary to master human functional anatomy and kinesiology.