Abnormal biomechanics of feet and their cause of hyperkeratoses.

A brief review of pedal anatomy and the mechanisms enabling feet to function as organs of locomotion is presented. The importance of the subtalar joint is emphasized. Four major abnormalities disturbing normal foot function are noted, and the most commonly encountered of these alterations, rearfoot varus, is discussed in some detail. A series of pedal abnormalities in rearfoot varus occurs because in the foot's attempt to overcome its imbalance, it pronates excessively and causes development of callus, corn, hallux valgus, and even ingrown toenail. Haglund's deformity, soft corn, and tailor's bunion are also secondary to the abnormality. Attempts to restrict the germinal compensatory pronation by various forms of padding of the medial aspect of the foot are frequently rewarded by restoration of asymptomatic feet. Surgical means of restoring normal function are briefly discussed.