hindlimb muscle mass quadriceps morphology trait quadriceps mass caripark 2018-12-04T14:34:22Z VT:0010806 Trait.ontology The amount of matter in the group of four muscles (rectus femoris, vastus intermedius, vastus lteralis, and vastus medialis) which extend down the front of the thigh and are the major extensors of the knee joint.