Posterior Abdominal Wall

Question 1

What’s the muscular floor of the posterior abdominal wall?

Answer 1

Psoas Major and Minor

Iliacus

Quadratus Lumborum

Diaphragm

Question 2

Psoas major + Minor?

where does psoas major come from?

what does psoas major do?

inserts to?

Answer 2

psoas major is the thick muscle going inferior to superior. Psoas minor is laying right on top of it.

psoas major comes from attaches to the transverse processes and vertebrae of T12 through lumbar vertebrae

major hip flexor, flexion of vertebral column and lateral bending of the vertebral column

the lesser trochanter

Question 3

Where is the Iliacus found?

what does this merge with to form the iliopsoas?

what movements?

Answer 3

iliac fossa

Iliacus + psoas = iliopsoas

hip flexor and stabilize the hip.

Question 4

Quadratus Lumborum?

Answer 4

attached to the 12th rib and the iliac crest

helps with posture and aids in lateral bending

Question 5

what does the diaphragm do?

Answer 5

inspiration.

Question 6

When you’re doing sit ups, what muscle are you working?

Answer 6

hip flexors.

Question 7

Psoas abcess?

symptoms? (5)

what kinds of people are affected? (3)

what sign are you looking for?

Answer 7

infection deep to the psoas fascia (between the fascia and the muscle)

1) back / flank pain (because its on the posterior wall)..
2) fever (because infection), can show as an inguinal mass because it inserts on lesser trochanter (so may think it’s a hernia)
3) limp (limping because it compresses the fascia and hurts)
4) anorexia, weight loss

you see it where tuberculosis is endemic –>(especially with refugees + American Indian locations)

So going through the lungs into the blood stream –> vertebral bodies –> since psoas attaches to vertebral bodies it’s easy for it to go in and cause one

Question 8

Fascial ligaments of the posterior abdominal wall??

Answer 8

Median Arcuate Ligament: goes right over the aorta (as the aorta enters through the hiatus of the diaphragm, that’s where we’ll see it

medial arcuate ligament = fascial thickening of the psoas major.

Lateral arcuate ligament: fascia over the quadratus lumborum muscle.

Question 9

what ligaments do the diaphragm attach to?

Answer 9

medial and lateral arcuate ligament

Question 10

What are the 3 parts of the muscular diaphragm?

where did the muscular diaphragm come from embryologically?

where did those come from?

Answer 10

Sternal (attaches to xiphoid)

Costal (attaches to the inferior 6 costal cartilages)

Lumbar (attaches to medial and lateral arcuate ligament)

abdominal wall –> hypomere

Question 11

What else are you going to see on the diaphragm?

embryologically where did each come from?

Answer 11

central tendon –> septum transversum

Crura = right and left crus –> came from dorsal mesentery of the esophagus

right crus is larger and longer (L3-L4).. it comes up, circles the esophagus and comes back down. (creating the esophageal hiatus) (happens in 70% of people)

Left crus = L2-L3 (shorter)

Question 12

What are the 3 apertures of the diaphragm? where are each located? What goes through each?

Answer 12

Caval opening –> located at T8.. this is where the IVC and Rt phrenic n. goes through (left phrenic pierces the diaphragm)

Esophageal Hiatus: Located at T10, esophagus, ant/post vagal trunks… also the esophageal arteries pass through this (from left gastric)

aortic hiatus: located at T12, aorta, thoracic duct, and sometimes the azygos and hemiazygos

Question 13

Adrenal glands are found where?

what are they covered in?

Right suprarenal gland relationships?

what is the left suprarenal gland relationships?

Answer 13

between the diaphragm and the kidneys.

they’re covered in renal fascia and this is attaching them to the right crus or the left crus (right adrenal gland = attached to right crus)

Inferior = kidney
superior and posterior = diaphragm
posterior = right crus
lateral to = IVC
Anterior/medial = Liver

inferior = kidney
superior and posterior = diaphragm
anterior = spleen, stomach, pancreas
posterior = left crus

Question 14

Blood supply for the adrenal glands? where do they come off from?

arteries and veins

Answer 14

superior suprarenal arteries ==> coming off of the inferior phrenic A.

middle suprarenal arteries ==> come from the aorta directly

inferior suprarenal arteries ==> coming from the renal arteries.

Veins ==> hormones need to get into the blood stream.

Right suprarenal right suprarenal vein –> goes into the IVC

left suprarenal vein –> drains into the left renal v.

Question 15

Innervation of the adrenal glands?

Answer 15

preganglionic sympathetics from T6-L2 that supply the adrenal gland.

Question 16

where is the postganglionic sympathetics located?

Answer 16

in the renal gland, NOT the suprarenal gland.

Question 17

What kidney sits higher? where do they sit?

Answer 17

left side (T12 - L3)

right side is lower because of the liver (1/2 inch) below that.

Question 18

posterior to the right and left kidneys?

what nerves would the kidneys also have posterior?

Answer 18

muscular floor –> including:

Psoas major muscle
quadratus lumborum, transversus abdominus

also the diaphragm

branches of L1 ilioinguinal and hypogastric and the subcostal nerve.

Question 19

anterior to the right kidney?

Answer 19

liver, duodenum, ascending colon

Question 20

anterior to the left kidney?

Answer 20

stomach, spleen, pancreas, jejunum, descending colon

Question 21

What covers the kidney?

what muscles are medial or lateral to the kidney?

Answer 21

perinephric fat (directly)
then fascia, then paranephric fat, then the muscles..

medial to the kidney = psoas major, lateral = anterior abdominal muscles
posterior = quadratus lumborum

Question 22

what do we do for a kidney transplant.. do we do anterior or posterior?

Answer 22

posterior wall

Question 23

Hilum of the kidney is located where?

what’s the most anterior structure of the hilum?

posterior to that?

posterior to that?

Answer 23

transpyloric plane (L1)

renal vein

renal artery

renal pelvis

Question 24

What are the posterior relationships to the ureter?

why is this clinically relevant?

Answer 24

posterior to the ductus (vas) deferens for the male

also posterior to the uterine artery (female)

if you do a hysterectomy and you think you ligated the uterine a artery but ligate the ureter you have caused a kidney problem.

Question 25

What are the 3 constriction points of the ureter (for a kidney stone)

Answer 25

ureteropelvic junction (renal pelvis to ureter)

crossing external iliac artery and/or pelvic brim

ureter enters the bladder wall.

Question 26

If you have an organ from the foregut, they’re going to drain via the what?

midgut?

hindgut structures?

after starting at these, where do they go?

Answer 26

celiac.

Superior mesenteric lymph nodes

inferior mesenteric lymph nodes

go to the lumbar –> cisterna chyli –> thoracic duct

Question 27

all lymphatic stuff from the abdomen and lower limbs goes where?

where is the cisterna chyli located?

Answer 27

eventually to the cisterna chyli (dilated structure at the very end of the thoracic duct) –> thoracic duct

L1ish level

Question 28

What covers a lot of the lumbar plexus?

Answer 28

psoas major m.

Question 29

what nerves are lateral to psoas major?

Answer 29

T12 = subcostal n (inferior to the 12th rib)

L1 splits into 2 = iliohypogastric is the more superior, ilioinguinal is inferior.

these 2 will pierce transverses abdomens around the ASIS to go between TA and IO… that’s where we lose contact with them.

the next is lateral cutaneous nerve of the. thigh –> this one dives deep to the inguinal ligament just medial to the ASIS

Femoral Nerve (HUGE) –> slightly under and lateral to psoas major.

Question 30

Nerve running anterior to psoas major?

Answer 30

running anterior to psoas major is genitofemoral N.

Question 31

Nerves running medial to psoas major?

Answer 31

Obturator N.

Lumbosacral trunks (lying on the ala.. this is the deepest nerves to see.

Question 32

function of iliohypogastric

Answer 32

sensation and innervating internal oblique and transverses abdominus..

posterolateral gluteal skin and pubic region sensation

Question 33

Obturator?

Answer 33

medial thigh sensory

motor = adductors (obturator externes, pectiques, muscles in medial thigh)

Question 34

Femoral N innervation?

Answer 34

Anterior thigh and medial leg. (sensory)

innervating the hip flexors (anterior medial thigh) and quads

Question 35

lumbosacral trunk gives rise to what?

Answer 35

sciatic.

Question 36

How can lower abdominal pain be worsened to see if you have a psoas abscess?

Answer 36

Psoas sign – muscle contraction (extending) and irritating that sign.

you extend the affected side, it puts pressure on that area. so the pt will want to put it in flexion to relax it.

Question 37

from the renal pelvis, what does it branch into and what are the structures?

Answer 37

renal pelvis –> major calyx –> minor calyx –> renal papilla –> goes into renal pyramids surrounded by renal cortex for the walls and renal columns separating the pyramids from one another

Question 38

Ilioinguinal motor and sensory function?

Answer 38

motor = internal oblique and TA

sensory = skin of upper medial thigh, over anterior scrotum or labium majora

Question 39

genitofemoral motor and sensory

Answer 39

motor = genital branch = male cremasteric muscle

sensory = genital branch = skin of anterior scrotum or labium majora = femoral branch = skin of upper anterior thigh

Question 40

lateral cutaneous nerve sensory?

Answer 40

skin on anterior and lateral thigh to the knee