- Discussion:
    - tibiotalar articular surface usually has slight lateral tilt, avg 3 deg;
    - empirical axis is in sl varus position, as indicated by talocrural ang;

- Mortise View:
    - talocrual anlge is formed by:
    - line drawn parallel to articular surface of distal tibia
    - line connecting tips of both malleoli (intermallellar line);
    - this angle is normally 8 - 15 degrees;
    - alternative method:
         - angle formed by perpendicular totibial articular surface & intermallellar line;
         - this angle is normally between 75 and 87 degrees;

- Shortening:
    - by either method this angle shoud be within 2 - 5  deg of opposite side;
    - difference of greater than this indicates fibular shortening;
    - displacements of lateral malleolus may be overestimated on x-ray compared w/ those on the computed tomography scans