What was the importance of mayellas brusies being primarily on the right hand side of her face?

it is important that Mayella has bruises on the right side of her face because it helps prove that Tom Robinson did not hit Mayella in her face. We know he did not hit her because when he was young he got his left hand stuck in a cotton gin and he cannot use his left hand. Because he cannot use his left hand, he certainly cannot hit with is left hand and if someone got hit on there right side of their face, the attacker is Left handed.