Posterior Abdominal Wall

Posterior Abdominal Wall Dr Sanjaya Kumar Shrestha

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Abdominal aorta Inferior vena cava Azygous and himiazygous veins- abdominal part Lymph nodes and cisterna chyli Muscles of posterior abdominal wall Thoracolumbar fascia Nerves- lumbar plexus and abdominal part of autonomic nervous system

The abdominal aorta 

Midline- aortic opening of diaphragm- level T12- L4 – divides into R and L iliac arteries

branches

Ventral branches -

Coeliac trunk Sup mesentric a Inf mesentric a

Lateral branches -

Inf phrenic a Middle suprarenal a Renal a Testicular or ovarian a

Dorsal branches -

Lumbar a – 4 pairs Median sacral a – unpairedsupplies rectum

Terminal branches -

R and L common iliac a

Inferior vena cava 

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Formed by union of R and L common iliac veins On the R side of body of L5 Ascends on R side of aorta Grooves posterior surface of liver Pierces central tendon of diaphragm – T8 level opens into lower and posterior part jof strium

tributaries

Common iliac veins 2. 3rd and 4th lumbar v – posteriior aspect of IVC (1st and 2nd lumbar v – may end in 3rd lumbar v, ascending lumbar v, azygous v on R, or hemiazugous v in L) (ascending lumbar v- an anastomotic channel- connects lateral sacral, iliolumbar and subcostal v.- lies within psoas m. – on joining subcostal v it forms- azygous v on R and hemiazygous v in L) 3 R testicular or ovarian vopens into IVC just below entrance of renal veins 1.

L gonadal v drains into L renal v. 4 Renal veins- receives L suprarenal and gonadal veins 5 R suprarenal vein 6 Hepatic veins- 3 large and many small veinsopen directly into the anterior surface of IVC just before it pierces the diaphragm

Clinical anatomy Thrombosis of IVC – edema of legs Collateral circulation  Superficialepigastric, circumflex iliac, lateral thoracic, thoracoepigastric, intrnal thoracic, posterior intrcostal , external pdendal, and lumbovertebral v Deep veinsAzygous, hemiazygous and lumbar v, vertebral venous plexus

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Abdominal part of azygous and hemiazygous veins

Lymph nodes of posterior abdominal wall

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External iliac Common iliac Lumbar or aortic nodes

External iliac nodes8-10, lies along ext iliac vessels Receives afferent from  Inguinal l n  Deeper layer of infraumbilical part of abd wall  Adductr region of thigh  Glans penis or clitoris  Membranous urethra  Prostate  Fundus of urinary bladder  Cervix uteri  Part of vagina

Common iliac nodes (4-6) - Afferents from- ext and int iliac nodes - Efferents to – latral aortic nodes

Lumbar or aortic nodes - Preaortic group - Lateral aortic gr - Retroaortic gr

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Preaortic nodes afferents fromsubdiaphragmatic part of GIT, liver, pancreas, spleen - efferents- intestinal trunks – enter – cisterna chyli lateral aortic nodes - afferents- from strs supplied by lateral and dorsal branches of aorta and from common iliac nodes- efferents from lumbar trunk- cisterna chyli Retroaortic nodes no particle area of drainage

Cisterna chyli 

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An elongated lymphatic sac (5-7cm) Situated in front of L1 and L2, immediately to the R of abd aorta Its upper end is continuous with thoracic duct Joined by R and L lumbar and intestinal lymph trunks

Muscles of posterior abd wall    

Psoas major Psoas minor Iliacus Quadratus lumborum

Clinical anatomy Psoas abscess Psoas enclosed in psoas sheath- a part of lumbar fasciaPus from tubercular inf of thoracic and lumbar vertebrae – track down through the sheath into the thigh – swelling of femoral triangle 

Nerves of posterior abd wall Lumbar plexus  Lies in the posterior part of the substance of psoas major muscle  Formed by – ventral rami of upper 4 lumbar nerves

Abdominal part of autonomic nervous system Sympathetic n – derived from 2 sources 1. Lumbar symp trunksupplies- somatic branches of lower abd wall and lower limbs - visceral branches- pelvic organs 2. Coeliac plexus- formed by splanchnic nerves from thorax- supplies- abdominal organs, including gonads

Parasympathetic nervesderived from 2 sources: 1. Vagus joins coeliac plexus 2. Pelvic splanchnic n joins inferior hypogastric plexus

Functions of ANS 

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In general, sympathetic n – vasomotor, motor to sphyncters, inhibitory to peristalsis and sensory to all viscera supplied Parasympathetic- motor and secretomotor to gut and glands associated with it

Cliniacal anatomy Visceral pain   1. 2. 3. 

Insensitive to cutting, crushing or burning Visceral pain- caused by Excessive distension Spasmodic contraction Ischemia Visceral pain is poorly localized- is dull in naturemay be felt in the skin or other somatic tissues, supplied by somatic n arising from the same spinal segment -- referred pain