Iliopsoas Muscles (Deep Group)

• Iliacus
  • Bony attachments:
    • 1. Superior 2/3 of iliac fossa, iliac crest to ala of sacrum & anterior SI ligament
    • 2. Tendon of psoas major, lesser trochanter of femur
  • Innervation: Femoral nerve (L2, L3, & L4)
  • Arterial supply: Iliolumbar artery (off internal iliac artery), lumbar artery
  • Action: Flexes the thigh & posturally stabilizes thigh in standing
• Psoas Major
  • Bony attachments:
    • 1. Anterior lateral surfaces of T12-L5 vertebrae and discs between them, transverse processes L1-L5
    • 2. Lesser trochanter of femur via its tendon with iliacus
  • Innervation: Ventral rami of lumbar nerves (L1, L2, & L3)
  • Arterial supply: iliolumbar artery off internal iliac artery, lumbar artery
  • Action: Flexes the thigh & posturally stabilizes thigh in standing
• Psoas Minor
  • Bony attachments:
    • 1. Anterior lateral surfaces of T12-L5 vertebrae and discs between them
    • 2. Pectineal line, iliopectineal eminence via iliopectineal arch
  • Innervation: Ventral rami of lumbar nerves (L1 & L2)
  • Arterial supply: Lumbar artery
  • Action: Weak flexor of thigh