Posterior Abdominal Wall

Question 1

boundaries
Superiorly-——-
Inferiorly- ——-
(a) bodies of — to —
(b) intervertecral disc between —-and —
(c) ——— ligament, anterior to and attached to the borders of the vertebrae
(d) ———
Rt crus- L— to L— vertebral bodies
Lt crus- L— to -L— vertebral bodies
Right and left crus are joined by the —— ligament

Answer 1

boundaries
Superiorly-12th rib articulating with T12 Inferiorly- Iliac crest of hip bone
(a) bodies of T12-L5
(b) intervertecral disc between T12and L5
(c) anterior longitudinal ligament, anterior to and attached to the borders of the vertebrae
(d) crura of the diaphragm
Rt crus- L1-L3 vertebral bodies Lt crus- L1-L2 vertebral bodies
Right and left crus are joined by the median arcuate ligament

Question 2

muscles
• 3 paired muscles each enclosed in fascia • which are:

Answer 2

muscles
• 3 paired muscles each enclosed in fascia • Psoas major
• Iliacus } often referred to as
iliopsoas
• Quadratus lumborum

Question 3

Origin of Psoas major

Answer 3

Psoas major
• Long, thick and fusiform in shape
• Origin
• Anterior surface and lower borders of the transverse processes of L1-L4 vertebrae
• 5 slips, each one arising from the bodies of adjacent vertebrae and intervertebral disc from T12- L5 vertebrae
• Tendinous arches which join the above

Question 4

psoas
• From origin it descends downwards and laterally along the brim of the pelvis, joined by —— to pass behind the inguinal ligament into the front of the thigh
• Insertion- ——-
• Nerve supply: direct branches of

Answer 4

psoas
• From origin it descends downwards and laterally along the brim of the pelvis, joined by Iliacus to pass behind the inguinal ligament into the front of the thigh
• Insertion- tip and medial part of the lesser trochanter of femur
• Nerve supply: direct branches L2,3,4

Question 5

Psoas minor
• Present in only —-%
• Lies on the —— surface of the Psoas major
• Attached to part of the fascia covering the——, ——- to the ——— and —-

Answer 5

Psoas minor
• Present in only 60%
• Lies on the anterior surface of the Psoas major
• Attached to part of the fascia covering the Psoas major, Iliacus to the pecten pubis and iliopubic eminence

Question 6

iliacus
• Origin?

Answer 6

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

Question 7

fascias
• Below continues over the psoas & Iliacus • (b) ——- fascia

Answer 7

fascias
• Below continues over the psoas & Iliacus • (b) Iliacus fascia (Fascia Iliaca)

Question 8

Applied Anatomy
• Psoas muscle is enclosed in the psoas sheath which is a compartment of the —- fascia-pus from a tuberculous infection of the lumbar vertebrae pass into the psoas sheath – Psoas abscess which may track down to the —-

Answer 8

Applied Anatomy
• The femoral artery lies on the Psoas tendon in the groin and the artery can be compressed against it
• Psoas muscle is enclosed in the psoas sheath which is a compartment of the lumbar fascia-pus from a tuberculous infection of the lumbar vertebrae pass into the psoas sheath – Psoas abscess which may track down to the femoral triangle

Question 9

The lumbar plexus is from — to —-

Answer 9

T12 to L4

Question 10

• The lumbar plexus is formed in the substance of the —— muscle.
• Its largest and most important branches are the ——— and ——— nerves, both of which spring from the segments L—,— and —

Answer 10

• The plexus is formed in the substance of the psoas muscle.
• Its largest and most important branches are the femoral and obturator nerves, both of which spring from the segments L.2,3 and 4

Question 11

Obturator nerve
• Runs to the upper part of the ——
• Appears from the —— side of the
psoas.
• Pierces —— fascia
• Crosses the—— joint
• Passes lateral to the ——— vessels and ureter and enters pelvis cavity.

Answer 11

Obturator nerve
• Runs to the upper part of the obturator
foramen.
• 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 12

Femoral nerve
• Lies —— to the femoral sheath
• Enters thigh behind ———
• Appears at the —— border of the psoas
• Runs down between psoas and iliacus
• Supplies iliacus within the false pelvis
Does the femoral nerve enter femoral sheath?

Answer 12

Femoral nerve
• Lies lateral to the femoral sheath
• 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
• DOES NOT ENTER THE FEMORAL SHEATH

Question 13

In addition to the femoral nerve, 4 other nerves appear at the lateral border of the psoas.

Answer 13

In addition to the femoral nerve, 4 other nerves appear at the lateral border of the psoas.
. The lateral femoral cutaneous nerve
. Ilioinguinal nerve
. Iliohypogastric nerve
. Subcostal nerve

Question 14

The lateral femoral cutaneous nerve
• comes from
•Enters the thigh behind the inguinal ligament lateral to the —- nerve.

Answer 14

The lateral feomal cutaneous nerve
• L.2,3
•Enters the thigh behind the inguinal ligament lateral to the femoral nerve.

Question 15

Ilioinguinal and iliohypogastric nerves
• Both from L.—
• Enter the abdomen behind the —— ligament and cross in front of the —— and pierce the —-,—-and——- aponeurosis before supplying the skin of suprapubic and inguinal regions.

Answer 15

Ilioinguinal and iliohypogastric nerves
• Both from L.1
• Enter the abdomen behind the medial arcuate ligament and cross in front of the quadratus and pierce the transversus,internal oblique and ext.ablique aponeurosis before supplying the skin of suprapubic and inguinal regions.

Question 16

The subcostal nerve
• Ventral ramus of T—
• Enters abd. Behind the —— ligament
• Pierces the transversus aponeurosis and then runs to enter the ——-.

Answer 16

The subcostal nerve
• Ventral ramus of T.12
• Not part of the lumbar plexus
• Enters abd. Behind the lateral arcuate ligament
• Pierces the transversus aponeurosis and then runs to enter the rectus sheath.

Question 17

The genitofemoral nerve
• comes from—-
• Pierces —— muscle and fascia
• Divides into 2 branches: —— and —— which descends in front of the —— muscle.

Answer 17

The genitofemoral nerve
• L.1 and 2
• Comes to lie within the extraperitoneal fatty tissue
• Pierces psoas muscle and fascia
• Divides into 2 branches: femoral and genital which descends in front of the psoas muscle.

Question 18

Femoral branch of genitofemoral nerve
•Supplies the skin of the ——-and pierces the ——-

Answer 18

Femoral branch of genitofemoral nerve
•Supplies the skin of the femoral triangle and pierces the fascia lata

Question 19

Genital branch of genitofemoral nerve
•Supplies the —— muscle and passes through the inguinal canal to supply the skin of the ——. In its course,it pierces the coverings of the spermatic cord.

Answer 19

Genital branch of genitofemoral nerve
•Supplies the cremaster muscle and passes through the inguinal canal to supply the skin of the scrotum. In its course,it pierces the coverings of the spermatic cord.

Question 20

Posterior abdominal wall comprises of 8 things:

Answer 20

• Lumbarvertebraeanddiscs.
• Muscles
oPsoas, quadratus lumborum, iliacus, transverse, abdominal wall oblique muscles.
• Nerves: Lumbar plexus
oVentral rami of lumbar spinal nerves.
• Fascia
• Diaphragm
oContributing to the superior part of the posterior wall
• Vessels : IVC, aorta and their branches
• lymph nodes
• Fat

Question 21

Posterior Abdominal Wall
Fascia
Between the parietal peritoneum and the muscles, list the fascia we can find

Answer 21

Posterior Abdominal Wall
Fascia
Between the parietal peritoneum and the muscles
• The psoas fascia or psoas sheath: Covers the psoas muscle
• The quadratus lumborum fascia: Covers the quadratus lumborum muscle
• The thoracolumbar fascia.

Question 22

Thoracolumbar fascia In the lumbar region, it consists of three layers:.

Answer 22

Posterior layer
Middle layer
Anteriorlayer

Question 23

Thoracolumbar fascia In the lumbar region, it consists of three layers:
Posterior layer is thick and is attached to the —— processes of the lumbar and —— vertebrae, and the —— ligament. From these attachments, it extends laterally to cover the ——— muscle
Middle layer is attached medially to the tips of the ——— processes of the lumbar vertebrae and —— ligaments; inferiorly, it is attached to the —— and, superiorly, to the——- Anteriorlayercoverstheanteriorsurfaceofthe ——— muscle and is attached medially to the ——- processes of the lumbar vertebrae, inferiorly; it is attached to the —— and, superiorly; it forms the ——- ligament for the attachment of the diaphragm.

Answer 23

Thoracolumbar fascia In the lumbar region, it consists of three layers:
i.
ii.
Posterior layer is thick and is attached to the spinous processes of the lumbar and sacral vertebrae, and the supraspinous ligament. From these attachments, it extends laterally to cover the erector spinae
Middle layer is attached medially to the tips of the transverse processes of the lumbar vertebrae and intertransverse ligaments; inferiorly, it is attached to the iliac crest and, superiorly, to the lower border of rib XII
iii. Anteriorlayercoverstheanteriorsurfaceofthe quadratus lumborum muscle and is attached medially to the transverse processes of the lumbar vertebrae, inferiorly; it is attached to the iliac crest and, superiorly; it forms the lateral arcuate ligament for the attachment of the diaphragm.

Question 24

Posterior Abdominal Wall
Muscles
Three paired muscles

Answer 24

Posterior Abdominal Wall
Muscles
Three paired muscles
• Psoas major
• Psoas minor • Iliacus
• Quadratus Lumborum

Question 25

Psoasmajor
– O:
– I:
– N:
– A:

Answer 25

Psoasmajor
– O: Lumbar transverse processes, intervertebral discs, and adjacent bodies from TXII to LV
– I: Lesser trochanter of femur via iliopsoas tendon
– N: Anterior rami of L1 to L3
– A: Thigh flexion, trunk flexion, lateral flexion

Question 26

Psoas minor
– O:
– I:
– N:
- A:
It is absent in about —% of the population

Answer 26

Psoas minor
– O: bodies and transverse processes of vertebrae Ll and L2
– I: descends on the anterior surface of the psoas major and inserts on the iliopubic eminence
– N: Anterior rami of L1 & L2 – A: Flexion of the lumbar
vertebrae
It is absent in about 40% of the population

Question 27

Quadratuslumborum
– O:
– I:
– N:
– A:

Answer 27

Quadratuslumborum
– O: iliac crest, lumbar fascia
– I:transverseprocesses of lumbar vertebrae and the 12th rib
– N: Anterior rami of T12 and L1 to L4
– A: Lateral Flexion of the vertebral column. Also an accessory muscle of respiration

Question 28

Iliacus
O:

I:
A:
N:

Answer 28

Iliacus
O: Iliac fossa
I: Lesser trochanter of femur
A: Flexes the thigh at the hip
N: Femoral Nerve

Question 29

The lumbar plexus
• Derived from the ventral rami of spinal nerves — to —-
• Formed within the substance of the ——
• Componentnervesare: –

Answer 29

The lumbar plexus
• Derived from the ventral rami of spinal nerves Ll to L5
• Formed within the substance of the psoas major
• Componentnervesare: – Ilioinguinal (L1)
– Iliohypogastric (L1)
– Genitofemoral (L1, L2)
– Lateral femoral cutaneous (L2, L3) – Femoral nerve (L2,3,4)
– Obturator nerve (L2,3,4)

Question 30

Iliohypogastric and ilioinguinal nerves (Ll)
o Both emerge from the —— border of psoas muscle, beneath the —— nerve.
o Ilioinguinal is (inferior/superior ?) to the iliohypogastric
o Both cross laterally over the—— muscle and then penetrate the —— muscle above the —— to enter the neurovascular plane

Answer 30

Iliohypogastric and ilioinguinal nerves (Ll)
o Both emerge from the lateral border of psoas muscle, beneath the subcostal nerve.
o Ilioinguinal is inferior to the iliohypogastric
o Both cross laterally over the quadratus lumborum and then penetrate the transversus abdominis above the iliac crest to enter the neurovascular plane

Question 31

Iliohypogastric and ilioinguinal nerves (Ll)
o The iliohypogastric supplies the skin of the ——— including the groin
o The ilioinguinal nerve enters the —- canal and is a component of the ——
o Emerges from the superficial inguinal ring to supply the skin of the —— and ———

Answer 31

Iliohypogastric and ilioinguinal nerves (Ll)
o The iliohypogastric supplies the skin of the lower abdomen including the groin
o The ilioinguinal nerve enters the inguinal canal and is a component of the spermatic cord
o Emerges from the superficial inguinal ring to supply the skin of the upper medial thigh and anterior scrotum/labium majus

Question 32

Genitofemoral nerve (Ll, 2)
o Emerges from the —— surface of the psoas major and descends on it
o Consists of a —— and a —— branch
o The genital branch enters the ——and, in the male, descends in the ———, supplying the —— muscle; distal to the superficial inguinal ring, it gives rise to cutaneous branches that supply the skin of the ——— and ———
o The femoral branch of the genitofemoral nerve accompanies the —— artery and supplies the skin of the ——

Answer 32

Genitofemoral nerve (Ll, 2)
o Emerges from the anterior surface of the psoas major and descends on it
o Consists of a genital and a femoral branch
o The genital branch enters the deep inguinal ring and, in the male, descends in the spermatic cord, supplying the cremaster muscle; distal to the superficial inguinal ring, it gives rise to cutaneous branches that supply the skin of the upper medial thigh and anterior scrotum/labium majus
o The femoral branch of the genitofemoral nerve accompanies the femoral artery and supplies the skin of the thigh

Question 33

Lateral femoral cutaneous nerve (L2, 3)
o Emerges about midway along the lateral border of the——
o Takes an oblique course across the —— muscle;
o Enters the thigh through or deep to the attachment of the —— at the anterior superior iliac spine
o supplies the skin of the ——

Answer 33

Lateral femoral cutaneous nerve (L2, 3)
o Emerges about midway along the lateral border of the psoas major
o Takes an oblique course across the iliacus muscle;
o Enters the thigh through or deep to the attachment of the inguinal ligament at the anterior superior iliac spine
o supplies the skin of the lateral thigh

Question 34

Femoral nerve (L,2, 3, 4)
o Descends in the gutter between the —— and —— muscles
o Enters the thigh deep to the ——
Supplies the —— and——- limb

Answer 34

Femoral nerve (L,2, 3, 4)
o Descends in the gutter between the psoas major and iliacus
o Enters the thigh deep to the inguinal ligament Supplies the flexor muscles and skin of the lower limb

Question 35

Obturator nerve (L2, 3, 4):
o Descends along the —— border of the psoas major
o Courses forward in the —— groove of the pelvic bone and then leaves the pelvis through the —— canal
o Supplies muscles and skin of the lower limb

Answer 35

Obturator nerve (L2, 3, 4):
o Descends along the medial border of the psoas major
o Courses forward in the obturator groove of the pelvic bone and then leaves the pelvis through the obturator canal
o Supplies muscles and skin of the lower limb

Question 36

• Lumbosacral trunk (L4, 5)
o Descends on the —— of the sacrum medial to the —— muscle
o Contributes to the —— plexus in the pelvis

Answer 36

• Lumbosacral trunk (L4, 5)
o Descends on the ala of the sacrum medial to the psoas major
o Contributes to the sacral plexus in the pelvis

Question 37

Lumbar sympathetic trunk
• Descend along the medial borders of the psoas major muscles; the left sympathetic trunk lies to the left of the —— and the right sympathetic trunk lies posterior to the ———
• The first two lumbar sympathetic ganglia are connected to their respective ventral rami by —— and —— rami communicantes
• the last three lumbar sympathetic ganglia are connected to their respective ventral rami by —- rami communicantes only
• This is because preganglionic sympathetic fibers do not exit the spinal cord below level L—
• Medial branches of the lumbar sympathetic ganglia form the——nerves

Answer 37

Lumbar sympathetic trunk
• Descend along the medial borders of the psoas major muscles; the left sympathetic trunk lies to the left of the abdominal aorta and the right sympathetic trunk lies posterior to the inferior vena cava
• The first two lumbar sympathetic ganglia are connected to their respective ventral rami by white and gray rami communicantes
• the last three lumbar sympathetic ganglia are connected to their respective ventral rami by gray rami communicantes only
• This is because preganglionic sympathetic fibers do not exit the spinal cord below level L2
• Medial branches of the lumbar sympathetic ganglia form the lumbar splanchnic nerves