Posterior Abdominal Wall & Lumbar Plexus

Question 1

The posterior abdominal wall is formed by…

Answer 1

…the lumbar vertebrae

• pelvic girdle
• posterior abdominal muscles and their associated fascia.

Question 2

Superior boundary of the posterior abdominal wall

Answer 2

12th rib articulating with T12

Question 3

Inferior boundary of the posterior abdominal wall

Answer 3

The Iliac crest of hip bone

Question 4

Posterior border of the PAW

Answer 4

• bodies of and intervertebral discs T12-L5
• anterior longitudinal ligament, anterior to and attached to the borders of the vertebrae
• crura of the diaphragm (right crus - L1-L3 vertebral bodies, left crus - L1-L2 vertebral bodies)

Question 5

The right and left crus of the PAW are joined by…

Answer 5

…the median arcuate ligament

Question 6

The right crus of the diaphragm is longer than the left. True or false?

Answer 6

True

Question 7

Muscles of the PAW

Answer 7

Psoas major
Psoas minor
Iliacus
Quadratus lumborum

Question 8

Shape of psoas major

Answer 8

Fusiform

Question 9

Origin of psoas major

Answer 9

Anterior surface and lower borders of the transverse processes of L1-L4 vertebrae

Question 10

How many slips make up psoas major?

Answer 10

5

Question 11

The slips of psoas major arise from

Answer 11

the bodies of adjacent vertebrae and intervertebral discs from T12- L5 vertebrae

Question 12

The slips of psoas major are joined by…

Answer 12

Tendinous arches

Question 13

Psoas major passes in front of the inguinal ligament into the front of the thigh. True or false?

Answer 13

False. It goes behind it.

Question 14

Insertion of psoas major

Answer 14

The tip and medial part of the lesser trochanter of femur

Question 15

Nerve supply of psoas major

Answer 15

Direct branches L2,3,4

Question 16

In what percentage of the population is there Psoas minor?

Answer 16

60%

Question 17

Psoas minor lies

Answer 17

On the anterior surface of the Psoas major

Question 18

Origin of psoas minor

Answer 18

The fascia covering psoas major, Iliacus.

Question 19

Psoas minor inserts into…

Answer 19

…the pectineal line and iliopubic eminence

Question 20

Origin of iliacus

Answer 20

• Upper 2/3 of Iliac fossa
• Inner lip of Iliac crest
• Upper surface of lateral part of the sacrum

Question 21

Insertion of iliacus

Answer 21

Inserts with psoas major into lesser trochanter

Question 22

Action of psoas major

Answer 22

Flexion of the thigh at the hip and lateral flexion of the vertebral column.

Question 23

Action of iliacus

Answer 23

Flexion of the thigh and lateral rotation of the hip

Question 24

Action of psoas minor

Answer 24

Flexion of the vertebral column.

Question 25

Innervation of iliacus

Answer 25

Femoral nerve L2 to L4

Question 26

The fascia of the PAW is one continuous sheet. True or false?

Answer 26

True

Question 27

The thoracolumbar fascia encloses which muscles?

Answer 27

Quadratus lumborum | Deep back muscles

Question 28

Origin of quadratus lumborum

Answer 28

It originates from the iliac crest and iliolumbar ligament.

Question 29

Insertion of quadratus lumborum

Answer 29

The transverse processes of L1 – L4 and the inferior border of the 12th rib

Question 30

Psoas muscle is enclosed in the psoas sheath. True or false?

Answer 30

True

Question 31

The lumbar plexus is formed by...

Answer 31

- the ventral rami of the 1st three lumbar nerves - part of the 4th - a twig from the subcostal nerve.

Question 32

The 1st ramus is joined by

Answer 32

a branch of the 12th thoracic nerve.

Question 33

What forms the lumbosacral trunk?

Answer 33

The lower half of the 4th ramus and the 5th ramus

Question 34

The lumbar plexus is formed where?

Answer 34

In the substance of the psoas muscle

Question 35

The largest and most important branches of the lumbar plexus are:

Answer 35

the femoral and obturator nerves

Question 36

The obturator and femoral nerves spring from what parts of the lumbar plexus?

Answer 36

The segments L 2,3 and 4

Question 37

What are the branches of the lumbar plexus?

Answer 37

``` Obturator Nerve Femoral Nerve Genitofemoral Nerve Iliohypogastric Nerve Ilioinguinal Nerve Lateral Cutaneous Nerve of Thigh ```

Question 38

Direction of the obturator nerve

Answer 38

* Appears from the medial side of the psoas. * Pierces psoas fascia * Crosses the sacro-iliac joint * Passes lateral to the int. iliac vessels and ureter and enters pelvis cavity.

Question 39

The obturator nerve runs to...

Answer 39

... the upper part of the obturator foramen.

Question 40

Direction of the femoral nerve

Answer 40

* Enters thigh behind inguinal ligament * Appears at the lateral border of the psoas * Runs down between psoas and iliacus * Supplies iliacus within the false pelvis

Question 41

The femoral nerve lies lateral to the femoral sheath and does not enter it. True or false?

Answer 41

True

Question 42

The nerves of the lumbar plexus appear...

Answer 42

at the lateral border of the psoas.

Question 43

The lateral femoral cutaneous nerve arises from...

Answer 43

L2,3

Question 44

The iliohypogastric and ilioinguinal nerves enter the abdomen in front of the medial arcuate ligament. True or false?

Answer 44

False. It’s behind it.

Question 45

The iliohypogastric and ilioinguinal nerves pierce the transversus, internal oblique and external oblique aponeurosis. True or false?

Answer 45

True

Question 46

Which nerves supply the skin of suprapubic and inguinal regions?

Answer 46

The iliohypogastric and ilioinguinal nerves

Question 47

The subcostal nerve is part of the lumbar plexus. True or false?

Answer 47

False

Question 48

The genitofemoral nerve divides into...

Answer 48

2 branches: femoral and genital which descend in front of the psoas muscle.

Question 49

The femoral branch of genitofemoral nerve supplies

Answer 49

the skin of the femoral triangle and pierces the fascia lata

Question 50

The genital branch of the genitofemoral nerve supplies...

Answer 50

...the cremaster muscle and the skin of the scrotum

Question 51

The genital branch of the genitofemoral nerve does not go through the inguinal canal but it pierces the coverings of the spermatic cord. True or false?

Answer 51

False, it does.