Posterior Abdominal Wall Flashcards
The left gonadal vein is a tributary to which other vein?
Left gonadal is a tributary to the left renal vein
Note, the right gonadal connects directly to the IVC.
What venous structures connect the common iliac vein and lumbar veins to the azygos (right side) and hemiazygos (left side) veins of the thorax?
ascending lumbar veins
Which kidney is lower, the left or right?
The right kidney is slightly lower than the left.
Through which vertebral levels does the kidneys typically extend?
T11 or 12-L3; note there is variation
Name the two layers of fat that surround the kidney. Describe their location.
- perirenal: deepest layer, closest to the kidney
2. pararenal: superficial layer,
Name the fascia that surrounds the two fat layers of the kidney.
Renal fascia
Note, be careful not to confuse this fascia with the renal capsule.
Which is more anterior, the renal artery or the renal vein?
The renal vein is anterior to the artery.
Over-under-over, how does this mneumonic relate to the relationship between the ureter, psoas muscle, gonadal vessels and common iliac artery?
The ureter is anterior or over the psoas muscle, posterior to the gonadal arteries and then courses anterior to the common iliacs
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?
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.
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.)
- kidney organ
- renal capsule
- perirenal fat
- pararenal fat
- renal fascia
From where do the sympathetic ganglion fibers that innervate the kidney arise?
- Greater, lesser & least thoracic splanchnic nerves
2. celiac plexus
List the three arteries that supply the suprarenal glands and their origin.
- superior suprarenal: branch from the inferior phrenic
- middle suprarenal: branch of the aorta
- inferior suprarenal: branch of the renal artery
Do the thoracic splanchnic nerves that are destined to the suprarenal glands synapse in any ganglion?
No, there go straight to the medulla of the gland.
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?
The post-ganglionic sympathetic axons innervate the blood vessels in the cortex of the gland.
The suprarenal glands are innervated by sympathetic fibers. When these fibers arrive to the glands, are they preganglionic or postganglionic?
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.
What nerves in general carry sympathetic preganglionic fibers to the suprarenal glands?
throracic splanchnic nerves
Where are the cell bodies of the sympathetic postganglionic neurons?
The sympathetic post-ganglionic neurons, for the suprarenal glands, are in the medulla of the gland itself.
What four muscles comprise the muscular framework of the posterior wall?
- Quadratus lumborum
- psoas major
- iliacus
- psoas minor
Which two posterior abdominal wall muscles function together and are known as the iliopsoas?
The iliacus and psoas major
Are the four muscles of the posterior wall innervated by visceral or somatic nerves?
These muscles (quadratus lumborum, psoas major, iliacus and psoas minor) are all skeletal muscles and thus innervated by somatic nerves.
What is the function of the quadratus lumborum?
It depresses and stabilizes rib 12; it is also responsible for limited lateral bending of trunk
From where does the quadratus lumborum receive its innervation?
ventral rami spinal nerves T12-L4
What is the function of the psoas major?
main flexor of hip; acts with the iliacus muscle as a single muscle referred to as the iliopsoas
From where does the psoas major receive its innervation?
ventral rami spinal nerves L1-3
What is the function of the iliacus muscle?
it is the main flex of the hip; acts with the psoas muscle referred to as a single muscle, he iliopsoas.
From where does the iliacus muscle receive its innervation?
femoral nerve
The nerves of the lumbar plexus are (somatic/visceral).
somatic
List the 3 types of fibers found in the lumbar plexus.
- somatic motor fibers
- somatic sensory fibers
- sympathetic postganglionic fibers
The ventral rami of spinal nerves L1-L4 combine to form the…
lumbar plexus
The nerves of the lumbar plexus provide innervation to…
- lower portion of the anterior abdominal wall
2. portions of the lower limb
List the six terminal branches of the lumbar plexus.
- iliohypogastric
- ilioinguinal
- genitofemoral
- lateral femoral cutaneous
- obturator
- femoral
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?
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.
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?
iliohypogastric and ilioinguinal
