Isolated tarsal bone fractures are rare. They are generally due to direct trauma or may be of the stress variety (Kohler's disease).

A	Lateral radiograph of the foot. There is a mildly displaced fracture of the navicular.

Links to online textbooks:

• Wheeless' Orthopedics: discussion of navicular stress fractures

Links to online cases:

• The Physician and Sports Medicine
• Podiatry at www.curtin.edu.au

References:

• Kiss ZS, Khan KM, Fuller PJ: Stress fractures of the tarsal navicular bone: CT findings in 55 cases AJR Am J Roentgenol. 1993 Jan;160(1):111-5.           [See related articles]
• Pavlov H, Torg JS, Freiberger RH: Tarsal navicular stress fractures: radiographic evaluation Radiology. 1983 Sep;148(3):641-5.           [See related articles]