Fig. 2.

Teflon sphere diameter measurements for $X$-, $Y$-, and $Z$-dimensions for 77 patients showing the entire range and quartiles of values for each dimension. Percent error (left axis) with respect to manufactured sphere specification and actual measurement values (right axis) are both shown. The measurement error for the $Z$-dimension is about six times higher than that of the $X$- and $Y$-dimensions.