Posterior Abdominal Wall Musculature

Question 1

Origin, insertion, Nerve, And actions of psoas. Major

Answer 1

O: lateral aspects and transverse processes of vertebral bodies and discs of T12-L5

I: lesser trochanter of femur via common tendon with iliacus

N: L2-L4 via lumbar plexus

A: flexes thigh at hip; with feet fixed flexes trunk on thigh (at hip joint). Acting unilaterally side-bends trunk to same side

Question 2

Origin, insertion, nerve, and actions of psoas minor.

Answer 2

O: lateral aspects of bodies of T12 and L1, plus their intervening discs

I: pectineal line on superior ramus of pubis

N: L1 and L2

A: assists in extension and flexion of trunk; acting unilaterally side bends trunk to same side

Question 3

What is the most lateral muscle of the posterior abdominal wall?

Answer 3

Quadratus lumborum

Question 4

Origin, insertion, nerve, and action of quadratus lumborum.

Answer 4

O: iliac crest and iliolumbar ligament

I: medial half of inferior border of 12th rib, tips of lumbar transverse processes

N: T12-L4

A: extends and laterally flexes vertebral column; fixes rib 12 during inspiration

Question 5

Origin, insertion, nerve, and action of iliacus

Answer 5

O: iliacus fossa of pelvis

I: lesser trochanter of femur via common iliopsoas tendon

N: femoral n (L2-4)

A: flexes thigh at hip, with lower limb fixed, flexes pelvis on thigh

Question 6

Describe the diaphragm.

Answer 6

• right and left domes

- superior surface extends upward as far as 5th rib

Question 7

What are the boundaries of the diaphragm?

Answer 7

• xiphisternal joint
• costal margin
• body of TV12

Question 8

What are the three peripheral origins insert on the central tendon of the diaphragm?

Answer 8

• sternal origin
• costal origin
• lumbar origin

Question 9

Which is longer the left or right crus? Where do they meet?

Answer 9

Right crus is longer and they meet at the aortic hiatus

Question 10

What structures form the posterior origins of the diaphragm? Where do these go?

Answer 10

-arcuate ligaments
+median arcuate ligament -> over aorta

+medial arcuate ligament -> over psoas major, sympathetic trunks

+lateral arcuate ligaments -> over. Quadratus lumborum, sub costal n, a and V

Question 11

What are the openings in the diaphragm and what travels through them?

Answer 11

• aortic hiatus (T12): aorta, thoracic duct
• esophageal hiatus (T10): esophagus, esophageal branches of left gastric a, ant and post vagal trucks, lymphatics
• vena cava formamen (T8): inf vena cava, terminal branched of rt phrenic n, lymphatics from the liver
• sternocostal hiatus: sup epigastric vessels

Question 12

What are arcuate ligaments also called?

Answer 12

-lumbocostal arches

Question 13

What is a potential site of herniation in the diaphragm?

Answer 13

-vertebrocostal (lumbocostal) triangle

Question 14

What are the vessels of the superior surface of the diaphragm?

Answer 14

-pericardiacophrenic, musculophrenic, superior phrenic a

Question 15

What are the vessels that supply the inferior surface of the diaphragm?

Answer 15

-inferior phrenic a and v
+from celiac trunk or aorta, right passes posterior to IVC, left posterior to esophagus, posterior branches give off superior suprarenal a

Question 16

What are the motor and sensory nerves of the diaphragm?

Answer 16

Motor:
-phrenic (C3-5) -> only motor nerves to diaphragm, branches run with inferior phrenic a

Sensory:
-phrenic n carries sensory n from central tendon

-intercostal n carry sensory fibers from peripheral part

Question 17

What are the nerves of the posterior abdominal wall?

Answer 17

• subcostal (T12)
• iliohypogastric (T12)
• ilioinguinal (L1)
• lateral cutaneous nerve of thigh (L1-2)
• femoral (L2-4)

Question 18

What are the two pathways of sympathetic innervation?

Answer 18

• splanchnic

- suprarenal

Question 19

What are the components of the renal system?

Answer 19

• kidneys
• suprarenal glands
• ureters
• urinary bladder
• urethra

Question 20

How is the vasculature of the kidney distributed? Name the arteries from superior to inferior.

Answer 20

-divided into five renal segments:

+superior segment -> superior/apical segmental arteries

+anterosuperior segment -> anterosuperior segmental artery

+anteriorinferior segment -> anteriorinferior segmental artery

+inferior segment -> inferior segmental artery

+posterior segment -> posterior segmental artery

Question 21

Outline the flow of urine.

Answer 21

-urine runs from renal papillae to minor calyses to major calyses to renal pelvis and finally ureter

Question 22

What are the posterior abdominal wall muscles?

Answer 22

• psoas major
• psoas minor
• quadratus lumborum
• transversus abdominis
• iliacus