Fig. 1

Calculation of the inclusion and separation indices. In each subfigure (a and b) is shown illustrated cross-sections of the distal tibia (left) and fibula (right). Lines A, B, and C are parallel. Line A represents the tibia incisure plane, drawn tangential to the most lateral aspects of the anterior and posterior colliculi of the tibia. Line B is tangential to the most lateral point of the fibula. Line C is tangential to the most proximal point of the tibia incisure. a The inclusion index is the shortest (perpendicular) distance from line A to line B (a), divided by the shortest distance from line A to line C (b), that is, a/b. b The separation index is the shortest distance from line A to line B (a), divided by the shortest distance from line A to line C (b), that is, a/b