Aflexor is a muscle that flexes a joint. In anatomy, flexion (from the Latin verb flectere, to bend)[1] is a joint movement that decreases the angle between the bones that converge at the joint. For example, one's elbow joint flexes when one brings their hand closer to the shoulder. Flexion is typically instigated by muscle contraction of a flexor.
The hip flexors are (in descending order of importance to the action of flexing the hip joint):[2]
Without the iliopsoas muscles, flexion in sitting position is not possible across the horizontal plane.[2]