HOD (metaphyseal osteopathy)
Alternating radiodense and radiolucent zones in the metaphysis of long bones, parallel to physis "double physeal line". This irregularity is due to necrosis of bone.
May progress to develop periosteal and extraperiosteal new bone around the metaphysis (bony reaction)
Often bilateral and often ulna and radius. Occurs in young dogs => growth plates are open.