Biplanar radiography was used to study normal growth of the left and r
ight radius in 5 Beagles and growth of the left radius alone in 15 add
itional Beagles. We explored the applicability of this radiographic me
thod in veterinary medicine by measuring the contribution to total rad
ius length from each growth plate. Spherical tantalum markers (0.5 mm)
were embedded in the proximal epiphysis, diaphysis, and distal epiphy
sis of each dog's radius at 10 weeks of age. Simultaneous biplanar rad
iographic views were obtained every 4 weeks until skeletal maturity wa
s documented. A three-dimensional coordinate system was constructed al
lowing for measurement of growth (in millimeters). Resolution of the m
easuring system was 0.074 mm. Mean +/- SEM length of the skeletally ma
ture Beagle's radius, as measured from proximal epiphyseal bead to dis
tal epiphyseal bead, was 95.33 +/- 1.07 mm, The percentage of contribu
tion to the total radius length from the proximal and distal growth pl
ates was 36.76 and 64.73%, respectively, with 95% confidence interval
of 2.29%. The percentage of contribution to radius length from the dis
tal radial growth plate increased for each consecutive time segment, w
ith the distal radial physis contributing 61.75% from 10 to 14 weeks o
f age and increasing to 70.22% from 22 to 26 weeks of age. Significant
growth was not observed after 26 weeks of age. The period of most rap
id growth was between 10 and 14 weeks of age. Biplanar radiography was
accurate and precise in quantifying the relative contribution of the
proximal and distal growth plate to radius length in Beagles. The meth
od is applicable in veterinary research or clinical medicine for monit
oring of axial and angular growth: physiologic, iatrogenic, or patholo
gic.