iliacus

noun

ili·​a·​cus i-ˈlī-ə-kəs 

plural iliaci -ə-ˌsī 

: a muscle of the iliac region of the abdomen that flexes the thigh or bends the pelvis and lumbar region forward, has its origin from the iliac fossa, iliac crest, the base of the sacrum, and adjoining parts, and is inserted into the outer side of the tendon of the psoas major, the capsule of the hip joint, and the lesser trochanter of the femur