Du hittar svaret i boken när mannen och pojken gick efter mannen som stal sin kundvagn:
Get away from the cart, the man said.
He looked at them. He looked at the boy. He was an outcast from one of the communes and the fingers of his right hand had been cut away. He tried to hide it behind him. A sort of fleshy spatula. The cart was piled high. He’d taken everything.
Get away from the cart and put down the knife.
~ Cormac McCarthy’s The Road, page 273 (Picador, London, 2007)
Det var ett straff för att lämna (eller bli sparkad ut) av en kommun.
Det finns en underbar tråd som diskuterar olika metoder och teorier om de saknade tummen här .