Posterior Abdominal Wall

Question 1

• What muscles make up the floor of the posterior abdominal wall?

Answer 1

• Psoas major and minor
• Iliacus
• Quadratus lumborum
• Diaphragm

Question 2

• Label the following structures

Answer 2

1. Quadratus lumborum m.
2. Diaphragm m.
3. Psoas major m.
4. Psoas minor m.

Question 3

• What is shown in the following image?
• What are signs and symptoms a patient with this condition would present with?
• What test can help you identify?

Answer 3

• Psoas abscess
• Back or flank pain
• Fever
• Inguinal mass
• Limp (lower abdominal pain exacerbated by extending limb)
• Anorexia
• Weight loss
• Psoas sign would be positive

Side note: more common in populations with tuberculosis

Question 4

• What are the fascial components of the posterior abdominal wall?

Answer 4

• Median arcuate ligament
• Medial arcuate ligament
• Lateral arcuate ligament

Question 5

• Median arcuate ligament

Answer 5

• Tendinous arch of the crura of the diaphragm

Question 6

• Medial arcuate ligament

Answer 6

• Fascial thickening of psoas fascia
• Located lateral to the median arcuate ligament

Question 7

• Lateral arcuate ligament

Answer 7

Thickening of the fascia lining quadratus lumborum

Question 8

• What two fascial components of the posterior abdominal wall serve as attachment points for the diaphragm muscle?

Answer 8

• Medial arcuate ligament
• Lateral arcuate ligament

Question 9

• Identify the fascial components of the posterior abdominal wall

Answer 9

• From top to bottom:
  
  • Median arcuate ligament
  • Medial arcuate ligament
  • Lateral arcuate ligament

Question 10

• What embryological structure gave rise to the muscular portion of the diaphragm?
• What are the parts of the muscular potion?

Answer 10

• Hypomere (mesoderm)
• Sternal part: attaches to xiphoid
• Costal part: attaches to inferior 6 costal cartilages
• Lumbar part: attaches to medial and lateral arcuate ligaments

Question 11

• What embryological structure gave rise to the central tendon of the diaphragm?

Answer 11

• Septum transversum

Question 12

• What embryological structure gave rise to the crura of the diaphragm?
• At what spinal levels are each crus located?

Answer 12

• Dorsal mesentary of the esophagus
• Right: L3-L4
• Left: L2-L3

Question 13

• What apertures are located in the diaphragm?

Answer 13

• Caval opening
• Esophageal hiatus
• Aortic hiatus

Question 14

• What runs through the caval opening of the diaphragm?
• What spinal level is it located?

Answer 14

• T8
• IVC and right phrenic nerve (remember that the left phrenic just pierces the diaphragm and does not go thru opening)

Question 15

• At what spinal level is the esophageal hiatus located?
• What runs through this hiatus?

Answer 15

• T10
• Esophagus
• Anterior and Posterior Vagal Trunks

Question 16

• At what spinal level is the aortic hiatus located?
• What structures run through it?

Answer 16

• T12
• Aorta
• Thoracic duct
• Sometimes azygos and hemi-azygos veins

Question 17

• Identify the apertures of the diaphragm

Answer 17

From top to bottom:

Caval opening

Esophageal hiatus

Aortic hiatus

Question 18

• Name the vascular relationships for the following:
  
  • Aorta
  • Celiac
  • SMA
  • Renals
  • Gonadal
  • IMA
  • Bifurcation

Answer 18

• Aorta-T12-L4
• Celiac: T12
• SMA: L1 (anterior to left renal vein)
• Renals: L1/L2
• Gonadal: L2
• IMA: L3
• Bifurcation: L4

Question 19

• At what spinal levels are the following structures located:
  
  • Body of pancreas and splenic vein
  • Left renal vein
  • Horizontal part of duodenum

Answer 19

• Body of pancreas and splenic vein: L1 and L2
• Left renal vein: L2
• Horizontal part of the duodenum: L3

Question 20

• Adrenal glands:
  
  • Blood supply
  • Innervation
  • Covered in renal fascia attaching to _

Answer 20

• Blood supply
  
  • Superior suprarenal a.
  • Middle suprarenal a.
  • Inferior suprarenal a.Innervation
    
    • Preganglionic sympathetics from T6-L2
    • Celiac plexus and splanchnic nerves
• Crura of the diaphragm

Question 21

• Relationships of the:
  
  • Right adrenal gland
  • Left adrenal gland

Answer 21

• Right
  
  • Right crus of diaphragm superiorly
  • Right kidney inferiorly
  • IVC
  • Liver anteromedially
• Left
  
  • Left crus of the diaphragm superiorly
  • Spleen
  • Stomach
  • Pancreas
  • Left Kidney

Question 22

• Relationships of:
  
  • Right kidney
  • Left kidney

Answer 22

• Right kidney
  
  • Right suprarenal gland superiorly
  • Muscular floor of the posterior abdominal wall posteriorly (diaphragm, psoas major and minor, quadratus lumborum and transversus abdominis)
  • Liver
  • Duodenum
  • Ascending colon
• Left kidney
  
  • Left suprarenal gland superiorly
  • Stomach
  • Spleen
  • Pancreas
  • Jejunum
  • Descending colon
• Posteriorly for both-muscular floor of posterior abdominal wall, L1 ilioinguinal and iliohypogastric nerves, subcostal nerves (T12)

Question 23

• Kidney anatomy

Answer 23

Question 24

• The ureters are POSTERIOR to _ in males and _ in females
• What are the three constriction points?

Answer 24

• Ductus deferens in males
• Uterine artery in females (careful of this during hysterectomy)
• Ureteropelvic junction
• Crossing external iliac artery and/or pelvic brim
• Uterer enters bladder wall

Question 25

* Lymphatics * _ lymph nodes drain foregut structures * _ lymph nodes drain midgut structures * _ lymph nodes drain hindgut structures

Answer 25

* Celiac * Superior mesenteric * Inferior mesenteric

Question 26

* Lymph flow: Starting from deep inguinal

Answer 26

* Deep inguinal * External iliac * Internal iliac * Common iliac * Lumbar/aortic/caval * Inferior mesenteric * **Cisterna chyli (dilated sac structure at the end of the thoracic duct)**

Question 27

* Important nerves of the lumbar plexus

Answer 27

* Iliohypogastric (L1) * Ilio-inguinal (L1) * Genitofemoral (L1-L2) * Lateral femoral cutaneous nerve (L2-L3) * Obrutator nerve (L2-L4) * Femoral nerve (L2-L4)

Question 28

* Important nerves of the posterior abdominal wall

Answer 28