Bohler's angle calcaneus fracture

This lateral radiograph shows a calcaneus fracture resulting in a Bohlers angle of about 18 degrees (arrow). The normal range is 20 to 40 degrees. Bohlers angle is formed by the intersection of two lines, one drawn from the most cephalic point of the calcaneal tuberosity (A) to the most cephalic point of the posterior articular facet (B), and the other drawn from point B to the most cephalic point of the anterior process (C). The arrowhead indicates the os trigonum, a normal accessory ossicle commonly mistaken for a fracture fragment.