1. Posterior abdominal wall
Sanjaya Adikari
Department of Anatomy

2. Objectives
Describe the arrangement of muscles and fascia in the posterior abdominal wall
Describe the structures found in the posterior abdominal wall
Describe the posterior abdominal viscera

3. Contents of abdominal cavity
Contents removed
Contents of abdominal cavity

4. Posterior abdominal wall
A musculoskeletal wall between the lower border of the rib cage and the pelvic brim
Marks the posterior boundary of the abdominal cavity
Anteriorly lie the retroperitoneal organs and the parietal peritoneum
Posteriorly lie muscles, fascia and the lumbar spine

5. Structures forming the posterior abdominal wall
Rib cage
peritoneum
cavity
Fat
Fascia
mesentery
Muscles
Bones
Pelvic brim

6. Retro-peritoneal structures
Organs
Abdominal aorta
IVC, Portal vein
Lymphatics
Nerves
Peritoneum

7. Paravertebral gutters
Forward projection is enhanced by aorta and IVC
lumbar lordosis
Floor is formed by psoas and quadratus lumborum above and iliacus below the iliac crest
Posterior part of the diaphragm also contributes

8. Psoas major and minor
Fibrous arches L1
Inguinal ligament

9. Psoas major muscle

10. Psoas major
Originates from bodies of T12 to L5, intervertebral disks and the medial end of transverse processors
Inserted into the lesser trochanter of the femur
Part above the medial arcuate ligament lies in the thoracic cavity
Flexes the hip and laterally flexes the lumbar spine
Both muscles acting together flexes the trunk

11. Quadratus lumborum Quadratus lumborum Iliolumbar ligament
Anterior sacroiliac ligament

12. Quadratus lumborum
Originates from transverse process of L5, iliolumbar ligament and iliac crest
Inserted into the transverse processes of L4 to L1 and the 12th rib medial half

13. Iliacus
Iliacus

14. Iliacus
Psoas major muscle
Iliacus
Common attachment
Originates from upper 2/3 of iliac fossa and anterior sacroiliac ligament thereby filling the illiac fossa
Inserted into the lesser trochanter of the femur trough a common tendon with the psoas major
Flexes the hip

15. Fascia of the posterior abdominal wall
Psoas fascia
Iliac fascia
Lumbar part of the thoracolumbar fascia

16. Psoas fascia Thick fascial sheath surrounding the psoas muscle
Arises as the muscle enters the abdominal cavity under the medial arcuate ligament
Ends at the pelvic brim as the muscle leaves the abdomen inferior to the inguinal ligament
(does not extend into the thigh)

17. Thoracolumbar fascia Extends from the back of sacrum to the neck
Binds erector spinae to vertebral column and encloses the quadratus lumborum
Very strong in the lumbar region
Laterally it gives origin to internal oblique and transversus abdominis muscles
Its lumbar part medially splits into three layers

18. Posoas fascia
Transversus abdominis
Posoas major muscle
Anterior layer
Middle layer
Internal oblique
Quadratus lumborum
Posterior layer
Erector spinae

19. L1
Inguinal ligament

20. Psoas abscess
A focus of pus in the lumbar intervertebral disks can track down along the muscle and present as a lump in the groin
Tuberculosis of the spine gives rise to a psoas abscess

21. Skeleton of the posterior abdominal wall include
Ischium
11th rib
12th vertebra
Sacrum
Intervertebral disks
Correct: B, C, D, E

22. Muscles of the posterior abdominal wall include
Iliopsoas
Erector spinae
Quadratus lumborum
Diaphragm
Transversus abdominis
Correct: A, C, D

24. Anterior layer of lumbar fascia
Psoas fascia
Lateral arcuate ligament
Medial arcuate ligament
Iliac fascia

25. Arcuate ligaments Lateral arcuate ligament Medial arcuate ligament
Median arcuate ligament
Formed by tendinous fibres from medial edges of left and right crura of the diaphragm
Lateral arcuate ligament
Medial arcuate ligament L1

26. Medial and Lateral arcuate ligaments
Sympathetic chain
Subcostal vessels and nerve
Abdominal aorta
Iliohypogastric nerve
Ilioinguinal nerve

28. Organs in the posterior abdominal wall
Duodenum 2nd and 3rd parts
Pancreas
Kidneys and ureters
Suprarenal glands

30. Vessels Aorta and its branches Inferior vena cava and its tributaries
Portal vein and its tributaries
Lymphatics and lymph nodes

31. Branches of abdominal aorta
Main branches are in three categories
Single ventral arteries to gut and its derivatives
Coeliac trunk, superior and inferior mesenteric
Paired arteries to other viscera
Suprarenal, renal, gonadal
Paired arteries to body wall
Inferior phrenic, lumbar

32. Branches of abdominal aorta
R. inferior phrenic art.
Coeliac trunk L5
T12
R. 4th lumbar art.
R. suprarenal art.
Superior mesenteric a.
R. renal art.
R. gonadal art.
Inferior mesenteric a.
Median sacral artery

33. Related structures Coeliac trunk T12 Splenic vein Body of pancreas
T.P.P
Superior mesenteric a.
L. renal vein
Un. pro. pancreas
3rd part duodenum
Inferior mesenteric a.
Median sacral artery

35. Lymph nodes Lymphatics follow arteries Pre-aortic nodes
Single ventral arteries
Paired arteries to other viscera
Paired arteries to body wall
Pre-aortic nodes
Para-aortic nodes

36. Lymph nodes

37. Internal iliac nodes
External iliac nodes
Common iliac nodes
Para-aortic nodes
Pre-aortic nodes
Cisterna chyli
Thoracic duct

38. Lumbar plexus 1st – 4th lumbar spinal segments Embeded in the psoas
Branches related laterally, medially or anteriorly to psoas

39. Branches of lumbar plexus & psoas muscle