Iliopsoas is a large compound muscle of the inner hip composed of the iliacus and psoas major muscle. … Their fibers merge into a single muscle belly around the pelvic brim. The iliopsoas ends in a tendon that inserts to the lesser trochanter of femur. The iliopsoas muscle is the main flexor of the hip joint.

For more information, see Iliopsoas muscle: Anatomy, function, supply, innervation.