Fig. 4

Trochlear groove measurements. (a) Both on axial and coronal JPEGs, identify the deepest, the most lateral and most medial points of the trochlear articular surface. Measure anterior α; posterior γ and distal β angles. (b) Draw the segment connecting the most lateral and medial point. (c) Draw its perpendicular through the deepest point and mark the crossing point of these two lines. (d) Calculate the ratio between width and depth of the articular surface in the anterior, posterior, and distal portion of the trochlea in both axial and coronal view