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Iliacus

Contents

Anatomy

General information

  • This section is strictly limited to anatomy, you might be looking for clinical relevant information which is found under the clinical chapters -- muscles section, click here to go to that page
  • The muscle unites distally with the psoas to become the iliopsoas

Position

  • Deep

Origin

  • Fossa iliaca
    • Upper 2/3
  • Spina iliaca anterior superior (SIAS)
  • Sacral ala

Insertion

  • Trochanter minor femur

Main function

  • Hip
    • Flexion
    • Lateral rotation
  • Pelvis
    • Anterior tilt

Secondary function

  • Pelvis
    • Contralateral rotation

Nerve innervation

  • Segmental
    • L1-L4
  • Peripheral
    • Femoral nerve

Arterial supply

  • Iliolumbar artery
  • Obturator artery

Palpation

  • Patient position
    • Supine
  • Note! Most of the iliacus muscle is too deep for palpation
  • Place a pillow under the patient's knees, so that the patient is lying with some flexion of the hips. Also place the leg in somewhat lateral rotation
  • Place your hands on the ventral part of illium and palpate in towards fossa iliaca with your fingers
  • Ask the patient to flex the hip and feel for the contraction in the muscle
  • Note! The femoral nerve, artery and vein are just above the iliopsoas (psoas major and iliacus) and pectineus in the area towards the insertion, so be careful when palpating in this area

Strength test

  • Patient position
    • Supine
  • Position the patient so that he/she is lying with light flexion, abduction and lateral rotation of the hip
  • Give resistance towards the anteromedial part of the lower tibia in a direction of extension and light abduction, so that the patient is giving force towards flexion and adduction (primarily in direction of flexion for the patient)

Weakness of the muscle

  • Is often seen in:
    • Lumbar kyphosis (bilateral weakness)
    • Lumbar scoliosis (unilateral weakness)