Iliopsoas

The iliopsoas is a muscle in the anterior compartment of the thigh. It is comprised of two separate muscles; the psoas major and iliacus. These muscles arise in the pelvis and pass under the inguinal ligament into the anterior compartment of the thigh – where they form a common tendon.

• Attachments:
  • Psoas major – originates from the lumbar vertebrae
  • Iliacus – originates from the iliac fossa of the pelvis.
  • They insert together onto the lesser trochanter of the femur.

• Actions: Flexion of the the thigh at the hip joint.

• Innervation:
  • Psoas major – anterior rami of L1-3
  • Iliacus – femoral nerve.
• Blood supply: Iliolumbar branch of the internal iliac artery, with contributions from the obturator and femoral arteries.

By TeachMeSeries Ltd (2025)

Fig 1
The muscles of the anterior thigh.