Midget Arm Syndrome
When a person has arms that are wider than they are long. This, giving the appearance that they are shorter than they actually are.
Person 1: "Wow Dan's arms are short!"
Person 2: "It's an illusion, he's got midget arm syndrome. They're 15" that's why..."
Person 2: "It's an illusion, he's got midget arm syndrome. They're 15" that's why..."