yes.
composed of two muscles Iliacus and psoas major Iliacus: prime mover for flexing thigh or for flexing trunk on thigh on thigh during a bow. Psoas major: same as iliacus, also effects latera flexion of vertebral column; important postural muscle.
weakness or tightness of the iliopsoas (psoas major/iliacus)
The iliopsoas muscle is stretched during hip extension. This muscle group is made up of the psoas major, psoas minor, and iliacus muscles. Stretching the iliopsoas can help improve hip flexibility and relieve hip tightness or discomfort.
The psoas major and the iliacus (which together make up the iliopsoas) are located in the abdomen but function to move the thigh. The psoas major originates on the body and transverse process of T12-L5. The iliacus originates on the iliac fossa of the ilium. They both insert on the proximal part of the femur.
hip flexor
The iliopsoas muscle is a composite of two muscles, the iliacus and the psoas major, which work together to flex the hip joint. The iliacus originates from the iliac fossa of the pelvis, while the psoas major originates from the lumbar vertebrae.
My assumption is you're talking about the muscle. The iliopsoas is made up of two different muscles; Iliacus (Which got it's name because it attaches to the Iliac Fossa of your pelvic. Ilium meaning "plank or flat" because it is the flat part of your pelvic.) and Psoas Major (Which translates to "Big Loin Muscle"). About halfway down Psoas Major the two attach, eventually sharing the same tendon so the names where joined together. Iliopsoas.
erector spinae? I believe it is the iliopsoas (combination of the psoas major, psoas minor, and iliacus.) On a sidenote it also flexes the thigh.
The iliopsoas muscle is located in the hip region. It is made up of two muscles - the psoas major and the iliacus - which connect the lumbar spine to the femur. It plays an important role in hip flexion and stability.
The Iliopsoas
Coccygeo-Iliacus Iliacus externus Iliolumbar Hope this helps!
Iliopsoas or Psoas Major