Hilchos Maasei Hakarbanos 9:10

The breast is the part of the animal that faces the ground, from the neck to the belly. Two ribs on each side are removed and given to the kohein along with it. The foreleg is from the upper joint until the ankle, i.e., two connected limbs. “Foreleg” means the right foreleg specifically. The analogous part of the hindleg is referred to as the thigh in all places.

Hilchos Maasei Hakarbanos 9:11

After waving all these things, they are burned on the altar except for the breast and thigh, which are eaten by the kohanim as per Leviticus 7:34: “the breast that was waved and the thigh that was raised....” The rest of a peace offering is eaten by the one who brought it. The kohanim do not acquire the breast and thigh of the offering until after the parts to be offered have been burned.