The Hip Flexors - Definition Health & Medical Medicine Last updated Saturday, June/01/2019 13 Share Updated January 01, 2014.Definition: The hip flexors are several muscles that bring the legs and trunk together in a flexion movement.The muscles that make up the hip flexors include:psoas majorilliacusrectus femorispectineussartorius Source... Medicine health Medications Drugs Medical 106 13 Share