rectus femoris
/ˈrɛktəs ˈfɛm(ə)rɪs/Anatomy and Zoology
noun
In humans: a long muscle of the thigh, originating from the ilium and acetabulum and inserting into the patellar tendon, forming part of the quadriceps femoris and serving to extend the leg. Also: a corresponding muscle in other vertebrates. More fully rectus femoris muscle.
Origin
Late 17th century. From post-classical Latin rectus + classical Latin femoris, genitive singular of femur.