1 - Posterior Abdomen

Question 1

Objectives: Explain the topography of the posterior abdominal wall

Question 2

Objectives: Identify the major muscles, nerves, and vessels within this region

Question 3

Objectives: Understand the anatomy of the diaphragm and its openings

Question 4

Objectives: Explain the location and structure of the kidney

Question 5

Quadratus Lumborum

Action

Innervation

Answer 5

• Action: Extend, Laterally flex trunk, fixes 12th rib during inspiration
• Innervation: T12 & L1-4

Question 6

Psoas Major

Action

Innervation

Answer 6

• A:
  
  • Flexes thigh and trunk
• I:
  
  • L2-L4 via lumbar plexus

Question 7

Iliacus

A

I

Answer 7

• A:
  
  • Flex thigh and trunk
• I:
  
  • L2-L4 femoral nerve

Question 8

Clinical: What can serve as an initial test for appendicitis?

Answer 8

Iliposoas Test

Move knee to chest on right side

Question 9

Diaphragm Openings?

Inferior Vena Cava Foramen

Esophageal Hiatus

Aortic Hiatus

What can occur at T12?

Answer 9

• Inferior Vena Cava Foramen
  
  • T8
  • IVC, R. Phrenic Nerve
• Esophageal Hiatus
  
  • T10
  • Esophagus, vagal trunks, esophageal branches of L. gastric vessels
• Aortic Hiatus (Red, White, Blue)
  
  • T12
  • Aorta, Thoracic Duct, Azygos Vein
  • Celiac Compression can occur here
• I 8, 10 Eggs, At noon (12)

Question 10

What is the source of the medial and lateral ligaments of the diaphragm?

What about the median?

Where are these three located?

Answer 10

• Medial and Lateral = thickenings of tranversalis fascia
• Median = crura of the diaphragm
• Median Arcuate Ligament:
  
  • Ant. to aorta, connection b/t L/R crura
• Medial Arcuate Ligament
  
  • Psoas Maj. fascia
• Lateral Arcuate Ligament
  
  • Quadratus Lumborum fascia

Question 11

What organs do the kidneys contact?

What are the fat/fascia layers that surround the kidney, superficial to deep?

What is the order of structures, anterior to posterior, at the Hilum?

What is unique about the blood supply of the kidneys?

Answer 11

• Liver, Stomach, Duodenym, Spleen, Pancreas, Colon
• Superficial to Deep:
  
  • Paranephric Fat
  • Renal Fascia
  • Perinephric Fat
  • Renal Capsule
• Hilum, Anterior to Posterior (VAP)
  
  • Renal VEIN
  • Renal ARTERY
  • Renal PELVIS
• Kidney blood supply
  
  • Segmental blood supply with end arteries
  • No anastomoses

Question 12

What three sites can ureter constriction occur? (kidney stone risk)

Answer 12

• Junction of Renal Pelvis and Ureter
• Pelvic Inlet
• Entrance to Bladder

Question 13

What is the blood supply to the suprarenal glands? (3x)

Answer 13

• Superior Suprarenal (from Inferior phrenic)
• Middle Suprarenal (from Aorta)
• Inferior Suprarenal (freom Renal Artery)

Question 14

Abdominal Aorta:

Unpaired visceral (3x)

Paired visceral (3x pairs)

Pairec parietal

Answer 14

• Unpaired Visceral
  
  • Celiac Trunk (T12)
  • Superior Mesenteric (L1)
  • Inferior Mesenteric (L3)
• Paired Visceral
  
  • Middle Suprarenal (L1)
  • Renal (L1)
  • Gonadal (L2) [testicular/ovarian]
• Paired Parietal
  
  • Inferior Phrenic (T12)
  • Subcostal (T12) [many]
  • Lumbar (L1-L4) [many]

Question 15

Where does the abdominal aorta bifurcation occur?

Where does the IVC lie? Where does the left renal vein cross? L Gonadal, L Suprarenal drainage? Right?

What is the result of such patterns with kidney problem presentation (especially in men)? What vessel specifically can cause this?

Answer 15

• Bifurcation into right and left (paired) common iliac arteries occurs at L4
• IVC lies to RIGHT of midline
  
  • Left Renal Vein crosses anterior to aorta
  • Left gonadal and suprarenal empty into left renal
  • Right gonadal/right suprarenal direct off IVC
• Kidney dysfunction can lead to testicular pain
  
  • ​Left side testes pain = check kidneys!
  • Superior Mesenteric Artery sits anterior to left renal vein

Question 16

Explain lymphatic drainage into the preaortic and para-aortic nodes

Where do these form a confluence?

Answer 16

• Para-aortic
  
  • Form Lumbar Trunks
• Pre-aortic
  
  • Form Intestinal Trunks
• Confluence at Cisterna Chyli where thoracic duct begins

Question 17

Nerve: Subcosta

Level:

Distribution:

Answer 17

• Nerve: Subcostal
• Level: T12
• Distribution: Skin and muscles of anterolateral abdominal wall

Question 18

Nerve: lliohypogastric

Level:

Distribution:

Answer 18

• Nerve: Iliohypogastric
• Level: L1
• Distribution: Skin of upper inguinal and suprapubic region; internal oblique and transversus abdominis muscle

Question 19

Nerve: Ilioinguinal

Level:

Distribution:

Answer 19

• Nerve: llioinguinal
• Level: L1
• Distribution: Skin of lower inguinal region, groun, medial thigh, interna oblique, and transversus abdominis muscle
• Passes through inguinal canal
• Cremasteric Reflex

Question 20

Nerve: Genitofemoral

Level:

Distribution:

Answer 20

• Nerve: Genitofemoral
• Level: L1, L2
• Distribution:
  
  • Genital Branch: Cremaster M.
    
    • ​Cremasteric Reflex
  • Femoral: Skin of medial thigh

Question 21

Nerve: Lateral Femoral Cutaneous

Level:

Distribution:

Answer 21

• Nerve: Lateral Femoral Cutaneous
• Level: L2, L3
• Distribution: Skin of lateral and anterior thigh

Question 22

Nerve: Femoral

Level:

Distribution:

Nerve: Obturator

Level:

Distribution:

Nerve: Lumbosacral Trunk

Level:

Distribution:

Answer 22

• Nerve: Femoral
• Level: L2-L4
• Distribution: Anterior thigh muscles
• Nerve: Obturator
• Level: L2-L4
• Distribution: Medial thigh muscles
• Nerve: Lumbosacral Trunk
• Level: L4-L5
• Distribution: Joins sacral plexus in pelvis