The weakness and disability of the foot which culminates in the deformity commonly known as flatfoot is progressive in character. In the earliest stage of the trouble there is present simply a weakness or strain, which causes the foot to assume a weakened position favoring additional strain. The weakened position is later present constantly during activity and soon becomes habitual, and from that it is only a short step to permanent weakness and deformity.
The various stages can be enumerated as follows: (1) weakness, and strain, (2) weakened position favoring more strain, (3) weak position in use, (4) habitual weak position, (5) permanent weak and deformed position.
The characteristic position of a weakened foot is the pronated or abducted position. In this position the front part of the foot is turned outward through the midtarsal joint with consequent lowering and weakening of the inner longitudinal arch. There is an apparent