Week 6- Posterior abdominal wall

Question 1

What is contained within the femoral sheath?

Answer 1

Vessels (artery, vein) inside, nerve is outside.

Question 2

Where does the quadratus lumborum attach?

Answer 2

The iliac crest- 12th rib- transverse processes of L1-L4.

Question 3

What occurs if both quadratus lumborum muscles contract? How does this differ if one contracts?

Answer 3

If both contract- pressure for forced expiration and supports the 12th rib.
If one contracts- flexes the trunk to one side.

Question 4

Where does the lateral arcuate ligament run?

Answer 4

Over the top of quadratus lumborum.

Question 5

Where does the iliacus attach? What does it join to form a bigger muscle?

Answer 5

Attaches from the iliac fossa (the curved part of the ilium) and joins the psoas to attach to the lesser trochanter of the femur
Joins psoas to from iliopsoas muscle.

Question 6

What is the function of the iliacus muscle?

Answer 6

It flexes the hip.

Question 7

What nerve supplies the iliacus muscle?

Answer 7

Femoral nerve.

Question 8

Where does the psoas muscle attach?

Answer 8

T12-L4 vertebral bodies and intervertebral discs superficially and L1-L5 deep to join the psoas muscle to attach to the lesser trochanter of the femur.

Question 9

What is the role of the psoas muscle?

Answer 9

Hip flexion.
Bends trunk laterally if only one contracts.
Raises trunk from supine position if both contract.

Question 10

Which nerve sits directly on the anterior surface of the psoas muscle?

Answer 10

Genitofemoral nerve.

Question 11

Which nerves supply the psoas muscle?

Answer 11

Lumbar plexus direct branches L2-4.

Question 12

At what level does the abdominal aorta enter the abdomen?

Which foramen does it go through?

Answer 12

At T12.

Goes through the aortic hiatus.

Question 13

At what level does the abdominal aorta bifurcate to form the common iliac arteries?

Answer 13

Bifurcates at L4.

Question 14

What does the IVC drain?

Answer 14

Blood from the body wall via the lumbar and sacral veins.
Blood from the diaphragm via the phrenic veins.
Blood from the kidneys and suprarenal glands.
Blood from hepatic veins.

Question 15

At what vertebral level is the IVC formed? What forms it?

Answer 15

The two common iliac veins join to form the IVC at L5.

Question 16

What do the lumbar veins drain. And where do they drain too?

Answer 16

Lumbar veins drain the posterior abdominal wall. There are 5.
1 and 2 drain to the ascending lumbar vein.
3 and 4 drain to the IVC
5 drains to the iliolumbar vein (into the common iliac).

Question 17

What do the ascending lumbar veins connect?

Answer 17

They connect the external iliac and lumbar veins to the azygous and hemiazygous systems.

Question 18

Where are the gonadal arteries coming from? What are their names in women and men?

Answer 18

Directly off the abdominal aorta at L2.
Women- ovarian artery
Men- testicular artery.

Question 19

Where do the ovarian and testicular veins drain to?

Answer 19

On the right side- directly into the IVC.

On the left side- into the renal vein

Question 20

What modality do the greater, lesser and least splanchnic nerves contain?

Answer 20

Hold sympathetic fibres.

Question 21

What modality do the pelvic splanchnic nerves contain?

Answer 21

Hold the parasympathetic fibres.

Question 22

What is the name of the plexus found around the bifurcation of the abdominal aorta?
What modalities does this plexus contain?

Answer 22

Superior hypogastric plexus

Contains both parasympathetic and sympathetic fibres.

Question 23

What is the name of the area where the intestinal lymph vessels come together?
What is it the start of?

Answer 23

Cisterna Chyli.

Its the start of the thoracic duct.

Question 24

Which nerve roots form the lumbar plexus?

Answer 24

Anterior rami of L1-L4.

Question 25

What is the most superior nerve from the lumbar plexus?
What are its nerve roots?
What does it supply?

Answer 25

The iliohypogastric nerve.
L1.
Sensory supply to lateral gluteal and pubic skin. Motor supply to internal oblique and transversus abdominus.

Question 26

What is the second most superior nerve from the lumbar plexus?
What are its nerve roots?
What does it supply?

Answer 26

Ilioinguinal nerve
L1.
Supplies sensory to the skin on the medial thigh and root of penis/scrotum or mons pubis/labia majora. Motor to internal oblique and transversus abdominus.

Question 27

Which nerve from the lumbar plexus is formed from anterior rami of L1 and L2?
Which muscle does it run anterior to?
What does it supply?

Answer 27

Genitofemoral nerve.

Runs anterior to the psoas muscle.
It supplies the sensory to scrotum or mons pubis and skin of the upper anterior thigh.
It supplies motor to cremasteric muscle.

Question 28

What are the nerve roots for the lateral cutaneous nerve of the thigh?
What does it supply?

Answer 28

Anterior rami of L2 and L3.

Sensory supply to skin on anterior and lateral thigh (above the knee).

Question 29

What are the nerve roots of the femoral nerve?

What does the femoral nerve supply?

Answer 29

L2,3 and 4.

Motor to the anterior compartment of the thigh, pectineous and iliacus.

Question 30

What are the nerve roots of the femoral nerve?

What does the femoral nerve supply?

Answer 30

L2,3 and 4.
Motor to the anterior compartment of the thigh, pectineous and iliacus.
Sensory to skin on anterior thigh and medial leg.

Question 31

What are the nerve roots of the obturator nerve?

Answer 31

L2, 3 and 4.
Supplies sensory to the skin on the medial thigh.
Supplies motor to the medial compartment of the thigh and obturator externus.