Root and coworkers175 describe a neutral position of the subtalar joint as that position of the joint in which the foot is neither pronated nor supinated; another way to state this is the position from which the subtalar joint could be maximally pronated and supinated. From this position, full supination ofthe normal subtalar inverts the calcaneus twice as many degrees as full pronation everts it. Subtalar neutral is two thirds from inversion and one third from eversion of the calcaneus. Clinically this is important because the subtalar neutral position provides a foundation for meaningful and valid measurements and observations with respect to the foot and entire leg. It is not only a basis for meaningful communication but also the foundation for the application of precise therapy, suchas the fabrication of an effective biomechanical orthotic device. There is also a direct clinical correlation between the subtalar joint and the midtarsal joint. When the subtalar joint is held in its neutral position, there is no longer the ability for the midtarsal joint to pronate. The midtarsal is unable to dorsiflex, evert, or abduct when the subtalar is in its neutral position. This position is termed the normal locking position of the midtarsal joint.