Simultaneous arthrography of the talocrural and talonavicular joints in children. III. Measurements on normal feet.

Simultaneous arthrography of the talocrural and talonavicular joints was performed on 32 normal feet from an autopsy material, and corresponding examinations were conducted clinically on 22 feet with no signs of deformity. The material comprised the age group 0 to 8 years. A linear correlation was observed between the length of the talus and the width of the talar trochlea. The radius and chord of the trochlear curvature increased proportionately with the length and trochlear width. These relationships were expressed as indices, by means of which the normal values for the radius and chord of the trochlea may be calculated for children up to 8 years of age. The mean value, standard deviation and tolerance limits were calculated for the central angle of the trochlear curvature and for the plantar and medial deviations of the talonavicular joint. These angles were found to be virtually constant between the neonatal period and the age of 8 years.