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Posterior abdominal wall
Sanjaya Adikari
Department of Anatomy
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
Contents of abdominal cavity
Contents removed
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
Structures forming the posterior abdominal wall
Rib cage
peritoneum
Fat
Fascia
Muscles
Bones
Pelvic brim
cavity
mesentery
Retro-peritoneal structures
Organs
Abdominal aorta
IVC, Portal vein
Lymphatics
Nerves
Peritoneum
Paravertebral
gutters
lumbar lordosis
Forward projection is
enhanced by aorta
and IVC
Floor is formed by psoas
and quadratus lumborum
above and iliacus below
the iliac crest
Posterior part of the
diaphragm also
contributes
Psoas major
and minor
L1
Fibrous arches
Inguinal ligament
Psoas major muscle
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
Quadratus
lumborum
Quadratus lumborum
Iliolumbar ligament
Anterior sacroiliac
ligament
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
Iliacus
Iliacus
Iliacus
• Originates from upper 2/3 of
iliac fossa and anterior
sacroiliac ligament thereby
filling the illiac fossa
• Inserted into the lesser
Psoas major muscle
Iliacus
trochanter of the femur trough
a common tendon with the
psoas major
• Flexes the hip
Common
attachment
Fascia of the posterior
abdominal wall
• Psoas fascia
• Iliac fascia
• Lumbar part of the thoracolumbar fascia
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)
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
Posoas fascia
Transversus
abdominis
Posoas major muscle
Anterior layer
Middle layer
Internal
oblique
Quadratus lumborum
Posterior layer
Erector spinae
L1
Inguinal ligament
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
Skeleton of the posterior abdominal wall
include
A. Ischium
B. 11th rib
C. 12th vertebra
D. Sacrum
E. Intervertebral disks
Correct: B, C, D, E
Muscles of the posterior abdominal wall
include
A. Iliopsoas
B. Erector spinae
C. Quadratus lumborum
D. Diaphragm
E. Transversus abdominis
Correct: A, C, D
Lateral arcuate
ligament
Medial arcuate
ligament
Anterior layer of
lumbar fascia
Psoas fascia
Iliac fascia
Arcuate
ligaments
L1
Lateral arcuate
ligament
Medial arcuate
ligament
Median arcuate
ligament
Formed by tendinous
fibres from medial edges
of left and right crura of
the diaphragm
Median arcuate
ligament
Medial and Lateral
arcuate ligaments
Subcostal vessels
and nerve
Iliohypogastric
nerve
Ilioinguinal nerve
Sympathetic chain
Abdominal aorta
Organs in the posterior abdominal wall
Duodenum 2nd and 3rd parts
Pancreas
Kidneys and ureters
Suprarenal glands
Vessels
• Aorta and its branches
• Inferior vena cava and its tributaries
• Portal vein and its tributaries
• Lymphatics and lymph nodes
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
Branches of abdominal aorta
Coeliac trunk
R. inferior phrenic art.
R. suprarenal art.
Superior mesenteric a.
R. renal art.
R. gonadal art.
R. 4th lumbar art.
Inferior mesenteric a.
Median sacral artery
Related structures
Coeliac trunk
T.P.P
Splenic vein
Body of pancreas
Superior mesenteric a.
L. renal vein
Un. pro. pancreas
3rd part duodenum
Inferior mesenteric a.
Median sacral artery
Lymph nodes
Lymphatics follow arteries
• Single ventral arteries
Pre-aortic nodes
• Paired arteries to other viscera
Para-aortic nodes
• Paired arteries to body wall
Lymph nodes
Thoracic duct
Pre-aortic nodes
Cisterna chyli
Para-aortic nodes
Common iliac nodes
External iliac nodes
Internal iliac nodes
Lumbar
plexus
1st – 4th lumbar
spinal segments
Embeded in the
psoas
Branches
related laterally,
medially or
anteriorly to
psoas
Branches of lumbar plexus & psoas muscle