Answered by: James L. Cook, DVM, PhD, DACVS, DACVSMR:
The growth plates are all susceptible to injury until the time of skeletal maturity (varies from about 9 months to 18 months of age depending on breed) because they are comprised of cartilage during growth. The distal ulnar growth plate may be more susceptible to injury that causes premature closure because of its relative size, shape and location. It is also relatively more problematic than some other growth plate injuries because it is responsible for 85% of the growth of the ulna and the radius and ulna must grow synchronously for forelimb alignment and elbow and wrist growth and function to be normal. Damage to the distal ulnar growth plate is typically caused by jump down injuries, falls, limbs getting caught in something, or motor vehicle accidents.