Objective: To (1) evaluate the normal extraosseous blood supply of the cranial aspect of the canine radius and (2) to compare the effects of minimally invasive (MIPO) and open plating technique on its preservation. Study Design: Experimental cadaveric study. Sample Population: Adult canine thoracic limbs (n=36) obtained from cadavers weighing 25-35kg. Methods: Twelve unpaired limbs were used to study the normal extraosseous blood supply. Each limb was injected with blue latex and India ink, and then underwent microdissection. Twelve paired limbs were used to study the effects of the 2 surgical plating techniques. On each of the paired radii, either MIPO or open plating was performed. After surgery, limbs were prepared and injected using the same methodology as the normal limbs. The dorsal surface of the radius was divided into 4 zones. Extravasation and periosteal filling were scored and the results were compared between groups using the Wilcoxon matched-pairs signed rank test; significance was set at P<.05. Results: The topography of the vasculature on the cranial aspect of the radius consisted of a complex network of periosteal vessels originating from the median, radial, caudal interosseous, and cranial interosseous arteries. Open plating caused significantly greater extravasation than MIPO (P=.0003). For each zone the MIPO group had significantly greater periosteal filling compared to those in the open plating group. Conclusions: In this cadaveric model, based on the superior periosteal filling and vascular integrity, MIPO disrupted less periosteal vasculature of the canine radius than open plating.