Measure Dog Chest Girth. Your yorkie’s size usually, harnesses are sized according to the neck and chest girths. Measure just behind the dog's front legs and up around the dog's ribcage.

To measure chest girth, start by holding one end of measuring tape on your dog’s spine.to measure the girth of your dog, measure the entire circumference of the chest.to measure the lower neck, make sure that the tape measure is positioned from the ridge between the shoulder blades to the top of the chest. Simply place one end of the tape measure on your dog’s spine, slightly above the broadest area of its rib cage. Measure around the entire chest.