Iliopsoas Anatomy: Origins, Insertions, Actions, Innervations

Iliopsoas Anatomy Study: Iliacus, Psoas Major, and Psoas Minor Muscles

Iliopsoas Muscle Group

Synergist:

  • Prime Movers:Pectineus, Tensor fascia latae, Adductor brevis, Sartorius
  • Accessory Movers:Adductor longus, Adductor magnus (anterior part), Gracilis, Gluteus minimus, Quadratus Lumborum

Antagonist:Gluteus maximus, Adductor magnus (posterior part)
Iliopsoas Anatomy

Iliacus

Origin: Superior two-thirds of the internal surface of the iliac fossa, the inner lip of the iliac crest, the ventral surface of the sacroiliac and iliolumbar ligaments, and the upper surface of the lateral part of the sacrum.
Insertion: The lesser trochanter of the femur after being joined by the tendon of psoas major. The conjoined tendon passes under the inguinal ligament to enter the thigh
Action: Flexion of thigh at hip, assists in extension of the lumbar spine
Innervation: Femoral nerve (L2, 3)
Blood Supply: Iliolumber artery from internal iliac artery

Primary Actions of the Iliacus:

1. Flexion of thigh at the hip

  • Agonists: Psoas Major
  • Antagonists: Gluteus maximus, Semitendinosus, Semimembranosus, Biceps Femoris (long head), Adductor magnus (posterior part)

2. Flexion of the pelvis at the hip

  • Agonists: Psoas Major
  • Antagonists: Gluteus maximus, Semitendinosus, Semimembranosus, Biceps Femoris (long head), Adductor magnus (posterior)

 




 

Psoas Major

Origin: Anterior surfaces of the transverse processes of T12-L5 vertebrae, the upper two thirds of the iliacus
Insertion: The lesser trochanter of the femur after being joined by the iliacus
Action: Flexion of thigh at hip, assists in extension of the lumbar spine
Innervation: Lumbar plexus (L2, 3,  4)

Primary Actions of the Psoas Major:

1. Flexion of thigh at the hip

  • Agonists: Iliacus
  • Antagonists: Gluteus maximus, Semitendinosus, Semimembranosus, Biceps Femoris (long head), Adductor magnus (posterior part)

Secondary Actions of the Psoas Major:

2. Assists with extension of the lumbar spine

  • Agonists: Iliocostalis lumborum, Longissimus thoracis
  • Antagonists: Rectus Abdominis

3. Lateral Flexion of the spine when acting unilaterally

  • Agonists: Iliocostalis lumborum, Longissimus thoracis, Quadratus lumborum, External and Internal Oblique
  • Antagonists: Iliocostalis lumborum, Longissimus thoracis, Quadratus lumborum, External and Internal Oblique on the opposite side.

Psoas Minor

Origin: Bodies of T12 and L1 and intervening intervertebral discs
Insertion: Fascia over the psoas major and iliacus
Action: Flexion of thigh at hip, assists in extension of the lumbar spine
Innervation: Ventral primary rami of L1
Blood Supply: Iliolumbar artery from internal iliac artery

Primary Actions of the Psoas Minor:
Because of its position and size the psoas minor is not a prime mover.

Secondary Actions of the Psoas Minor:

1. Assists with flexion of the thigh at the hip

  • Agonists: Psoas Major, Iliacus
  • Antagonists: Gluteus maximus, Semitendinosus, Semimembranosus, Biceps Femoris (long head)

For pain and symptom information see: Iliopsoas Muscle: Low Back, Abdomen, Groin, Pelvic, Upper Leg Pain


coloring_book

Recommended Anatomy Study Books
The Anatomy Coloring Book is one of the best study and reference books for beginning anatomy students. The diagrams are clearly labeled and allow you to see the relationship and placement of the various structures of the body. You will also be surprised how the act of coloring will help with recall. But this is not just a beginners book, it is also great for practitioners and therapists to have on hand to use with clients and patients to use as a visual reference.
basic_clinical_massa

 

Out of the scores of books in my office Basic Clinical Massage Therapy is by far the most referenced book in my library. The musculoskeletal system is overlaid on human models allowing you to learn the precise location, origin and insertions of each muscle. The models are pictured in various poses throughout the book which also helps you visualize muscles in motion and their actions relationship with the skeletal structure and other muscles. Though it is written for massage therapists, it is an excellent book for anyone who wants to learn about the muscular system. MT’s will benefit from recommended treatments for each muscle.


 



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