[6] Retroperitoneum, Posterior Abdominal Wall, and Lumbar Plexus

Question 1

Anterior Boundary of the Retroperitoneum

Answer 1

Peritoneum

Question 2

Posterior Boundary of the Retroperitoneum

Answer 2

Spine
Psoas
Quadratus Lumborum

Question 3

Superior Boundary of the Retroperitoneum

Answer 3

12th Ribs and Attachments of Diaphragm

Question 4

Inferior Boundary of the Retroperitoneum

Answer 4

Pelvic Brim

Question 5

Lateral Boundary of the Retroperitoneum

Answer 5

Lateral Borders of Quadratus Lumborum

Question 6

Contents of the Retroperitoneum (9)

Answer 6

• S – Suprarenal glands (the adrenal glands)
• A – Aorta / Inferior vena cava (great vessels)
• D – Duodenum (second and third segments)
• P – Pancreas (except tail which is intraperitoneal)
• U – Ureters
• C – Colon (only ascending and descending branches)
• K – Kidneys
• E – Esophagus
• R – Rectum

Question 7

Define: Primarily Retroperitoneal

Answer 7

Organs that were retroperitoneal ever since embryonic development

Question 8

Anatomic Zones of the Retroperitoneum (3)

Answer 8

1. Centromedial
2. Lateral
3. Pelvic

Question 9

In which Anatomic Zone is operation mandatory in the event of a hematoma?

Answer 9

Centromedial Zone, because the bleed may be coming from either the Abdominal Aorta or IVC which could lead to death from blood loss

Question 10

3 Diaphragmatic Apertures

Answer 10

Caval Opening
Esophageal Hiatus
Aortic Hiatus

Question 11

At what levels are the apertures of the diaphragm found?

Answer 11

Caval Opening: T8
Esophageal Hiatus: T10
Aortic Hiatus: T12

Question 12

What muscle is commonly known as “Tenderloin”

Answer 12

Psoas Major

Question 13

Function: Psoas Major

Answer 13

Chief Flexor of Thigh and Trunk

Question 14

Define: ( + ) Psoas Sign

Answer 14

Pain when:

(a) Supine Position: Right leg raised against resistance
(b) Thigh is extended while patient is lying on left side

Question 15

Define: Rovsing’s Sign

Answer 15

Palpation of Left Lower Quadrant increases pain felt in Right Lower Quadrant

Question 16

Define: Obturator Sign

Answer 16

Indicates irritation of the obturator internus muscle;
positive sign is pain following flexion and internal rotation of the hip and is performed by having the patient lie on his back with the hip and knee both flexed at 90° at which point the examiner holds the patient’s ankle with one hand and knee with the other hand then moves the patients ankle away from the body while allowing the knee to move only inward

Question 17

Function: Iliacus Muscle

Answer 17

• Aids the psoas in flexing the thigh and trunk

- Stabilizer of the hip joint

Question 18

Innervation: Iliacus Muscle

Answer 18

L2-L4

Question 19

Function: Quadratus Lumborum

Answer 19

Lateral bending of the trunk

Question 20

Innervation: Quadratus Lumborum

Answer 20

Ventral Rami of L1-L3

Question 21

Level of the Aortic Hiatus

Answer 21

T12 to L4, where it bifurcates

Question 22

Compression of the Abdominal Aorta is done by pushing it against what vertebrae?

Answer 22

L4, because it is more “superficial” due to lumbar lordosis

Question 23

Which vein in the PAW does not contribute directly to the IVC?

Answer 23

Left Gonadal Vein (Enters the Left Renal Vein first)

Question 24

Can the IVC be ligated?

Answer 24

Yes but only infrarenally, if done suprarenally the kidneys could lose blood supply and result to kidney failure

Question 25

What does the Suprarenal Cortex produce?

What does the Suprarenal Medulla produce?

Answer 25

C: Corticosteroids and Androgens
M: Catecholamines