Fig. 1.

Inferior view of the lower femoral epiphysis. A, maximum altitude of the lateral margin of the patellar groove (millimetres); B, minimum altitude of the lowest point of the groove (millimetres); C, maximum altitude of the medial margin of the patellar groove (millimetres); D, width of the lateral side of the anterior patellar groove (millimetres); E, width of the medial side of the anterior patellar groove (millimetres); θL, angle formed by a line passing through the point of maximum lateral altitude and the lowest point of the groove and the horizontal (degrees); θM, angle formed by a line passing through the point of maximum medial altitude and the lowest point of the groove and the horizontal (degrees); α, angle of patellar groove, enclosed by the medial and the lateral aspect (degrees).