Musannaf Ibn Abi Shayba 18:226

Abu Bakr narrated to us, he said: Waki' narrated to us, he said: Sufyan narrated to us, from Jabir, from 'Amir, who said: If the hand is severed from the joint, then in it is half of the blood money. And if it is severed from the upper arm, then in it is half of the blood money.