Definition of iliacus in US English:


(also iliacus muscle)


  • A triangular muscle which passes from the pelvis through the groin on either side and, together with the psoas, flexes the hip.

    • ‘Gluteus medius and iliacus muscles are seen for the first time.’
    • ‘The psoas lies deep in the abdomen; the iliacus lies to the side of the psoas on the inner surface of the ilium, the side bone of the hip.’
    • ‘The femoral nerve may run buried in a cleft of the iliacus under the psoas.’
    • ‘The iliacus muscle, sharing a tendon with the psoas at the lesser trocanter, fans up and opens, lining the inside of each ilium.’
    • ‘Accessory fasciculi may unite the pectineus with the obturator externus, the iliacus, the capsule of the hip, or the lesser trochanter.’


Early 17th century: from late Latin.