Musannaf Ibn Abi Shayba 19:90

Abu Bakr narrated to us, he said: 'Abdah bin Sulayman narrated to us, from Yahya, from Sulayman bin Yasar, he said: A boy who had stolen was brought to Umar. He ordered him to be measured, so he was measured and found to be six spans minus a fingertip, so he let him go. The boy was then named Numaylah (Little Fingertip).