Posterior Abdominal Wall

Question 1

The left gonadal vein is a tributary to which other vein?

Answer 1

Left gonadal is a tributary to the left renal vein

Note, the right gonadal connects directly to the IVC.

Question 2

What venous structures connect the common iliac vein and lumbar veins to the azygos (right side) and hemiazygos (left side) veins of the thorax?

Answer 2

ascending lumbar veins

Question 3

Which kidney is lower, the left or right?

Answer 3

The right kidney is slightly lower than the left.

Question 4

Through which vertebral levels does the kidneys typically extend?

Answer 4

T11 or 12-L3; note there is variation

Question 5

Name the two layers of fat that surround the kidney. Describe their location.

Answer 5

1. perirenal: deepest layer, closest to the kidney

2. pararenal: superficial layer,

Question 6

Name the fascia that surrounds the two fat layers of the kidney.

Answer 6

Renal fascia

Note, be careful not to confuse this fascia with the renal capsule.

Question 7

Which is more anterior, the renal artery or the renal vein?

Answer 7

The renal vein is anterior to the artery.

Question 8

Over-under-over, how does this mneumonic relate to the relationship between the ureter, psoas muscle, gonadal vessels and common iliac artery?

Answer 8

The ureter is anterior or over the psoas muscle, posterior to the gonadal arteries and then courses anterior to the common iliacs

Question 9

Over-under-over-under, how does this mneumonic relate to the relationship between the ureter, psoas muscle, gonadal vessels, common iliac artery and uterine artery in women?

Answer 9

The ureter is anterior or over the psoas muscle, posterior to the gonadal arteries and then courses anterior to the common iliacs. As the ureter descends to join the postero-lateralaspect of the urinary bladder, it courses under or posterior to the uterine artery.
This relationship only exists in women.

Question 10

List the layers/tissues you’d find going from the kidney organ towards the periphery. (i.e. what layer connective tissue would you reach, then what layer or fat, etc.)

Answer 10

1. kidney organ
2. renal capsule
3. perirenal fat
4. pararenal fat
5. renal fascia

Question 11

From where do the sympathetic ganglion fibers that innervate the kidney arise?

Answer 11

1. Greater, lesser & least thoracic splanchnic nerves

2. celiac plexus

Question 12

List the three arteries that supply the suprarenal glands and their origin.

Answer 12

1. superior suprarenal: branch from the inferior phrenic
2. middle suprarenal: branch of the aorta
3. inferior suprarenal: branch of the renal artery

Question 13

Do the thoracic splanchnic nerves that are destined to the suprarenal glands synapse in any ganglion?

Answer 13

No, there go straight to the medulla of the gland.

Question 14

If the sympathetic preganglionic nerve fibers from the thoracic splanchnic nerves synapse directly on cells in the medulla of the suprarenal gland (which act as post ganglionic cells), where do the post-ganglionic axons project?

Answer 14

The post-ganglionic sympathetic axons innervate the blood vessels in the cortex of the gland.

Question 15

The suprarenal glands are innervated by sympathetic fibers. When these fibers arrive to the glands, are they preganglionic or postganglionic?

Answer 15

The suprarenal glands are only under sympathetic modulation. When sympathetic fibers arrive, they are sympathetic pre-ganglionic fibers.

The cells in the medulla itself act as post-ganglionic sympathetic neurons.

Question 16

What nerves in general carry sympathetic preganglionic fibers to the suprarenal glands?

Answer 16

throracic splanchnic nerves

Question 17

Where are the cell bodies of the sympathetic postganglionic neurons?

Answer 17

The sympathetic post-ganglionic neurons, for the suprarenal glands, are in the medulla of the gland itself.

Question 18

What four muscles comprise the muscular framework of the posterior wall?

Answer 18

1. Quadratus lumborum
2. psoas major
3. iliacus
4. psoas minor

Question 19

Which two posterior abdominal wall muscles function together and are known as the iliopsoas?

Answer 19

The iliacus and psoas major

Question 20

Are the four muscles of the posterior wall innervated by visceral or somatic nerves?

Answer 20

These muscles (quadratus lumborum, psoas major, iliacus and psoas minor) are all skeletal muscles and thus innervated by somatic nerves.

Question 21

What is the function of the quadratus lumborum?

Answer 21

It depresses and stabilizes rib 12; it is also responsible for limited lateral bending of trunk

Question 22

From where does the quadratus lumborum receive its innervation?

Answer 22

ventral rami spinal nerves T12-L4

Question 23

What is the function of the psoas major?

Answer 23

main flexor of hip; acts with the iliacus muscle as a single muscle referred to as the iliopsoas

Question 24

From where does the psoas major receive its innervation?

Answer 24

ventral rami spinal nerves L1-3

Question 25

What is the function of the iliacus muscle?

Answer 25

it is the main flex of the hip; acts with the psoas muscle referred to as a single muscle, he iliopsoas.

Question 26

From where does the iliacus muscle receive its innervation?

Answer 26

femoral nerve

Question 27

The nerves of the lumbar plexus are (somatic/visceral).

Answer 27

somatic

Question 28

List the 3 types of fibers found in the lumbar plexus.

Answer 28

1. somatic motor fibers
2. somatic sensory fibers
3. sympathetic postganglionic fibers

Question 29

The ventral rami of spinal nerves L1-L4 combine to form the…

Answer 29

lumbar plexus

Question 30

The nerves of the lumbar plexus provide innervation to…

Answer 30

1. lower portion of the anterior abdominal wall

2. portions of the lower limb

Question 31

List the six terminal branches of the lumbar plexus.

Answer 31

1. iliohypogastric
2. ilioinguinal
3. genitofemoral
4. lateral femoral cutaneous
5. obturator
6. femoral

Question 32

The ventral ramus of spinal nerve T12 can also be seen on the posterior abdominal wall. It is called the subcostal T12. Is it a part of the lumbar plexus?

Answer 32

No, the lumbar plexus is comprised of ventral rami from L1-L4. The ventral ramus of spinal nerve T12 is called the subcostal T12, and is NOT a part of the lumbar plexus. It can be used as a landmark.

Question 33

Imagine you are a urologist and you have to gain access to the kidney from a posterior approach. What two nerves should you be aware of in a posterior approach to the kidney?

Answer 33

iliohypogastric and ilioinguinal