Posterior Body Wall

Question 1

Composition of the Posterior Body Wall

Answer 1

1. 5 lumbar vertebrae and discs
2. Psoas Major
3. Psoas Minor
4. Quadratus Lumborum
5. Ilium
6. Iliacus
7. Posterior Part of Diaphragm

Question 2

Psoas Major (Origin and Insertion)

Answer 2

• Origin: Lumbar Vertebrae
• Insertion: Femur
• Action: Flexor of Thigh and Trunk

Question 3

Iliopsoas

Answer 3

• Fusion of the Psoas Major and Iliacus

- Action: Flexor of the Thigh and Trunk

Question 4

Iliacus (Origin and Insertion)

Answer 4

• Origin: Iliac Fossa
• Insertion: Femur
• Action: Flexor of the Thigh and Trunk

Question 5

Psoas Minor

Answer 5

• Very small and commonly missing
• Recognized by tendon on Psoas Major
• Follows Psoas Major

Question 6

Quadratus Lumborum (Origin and Insertion)

Answer 6

• Origin: 12th rib
• Insertion: Iliac Crest
• Action: Bends trunk ipsilaterally, aids in forced expiration

Question 7

What is the innervation of the muscles of the posterior body wall?

Answer 7

The Lumbar portion of the Lumbosacral plexus