3 verses have
backs
in Edition Clear Qur'an by Talal Itani / Al-An'aam (The Cattle)

6:31Losers are those who deny the encounter with God. Then, when the Hour comes upon them suddenly, they will say, “Alas for us, how we have neglected it.” And they will carry their burdens on their backs—evil is what they carry.

6:138And they say, “These animals and crops are restricted; none may eat them except those we permit,” by their claims, and animals whose backs are forbidden, and animals over which they do not pronounce the name of God—fabricating lies against Him. He will repay them for what they used to invent.

6:146For the Jews We forbade everything with claws. As of cattle and sheep: We forbade them their fat, except what adheres to their backs, or the entrails, or what is mixed with bone. This is how We penalized them for their inequity. We are indeed truthful.