Abdominal wall - ANATOMY

Question 1

How is the abdominal wall separated?

Answer 1

Into 9 regions, divided by the mid-clavicular, subcostal and intertubular planes

Question 2

Name the 9 regions of the abdomen

Answer 2

Epigastric
Left hypochondriac
Right hypochondriac

Umbilical
Left and right lumbar

Suprapubic
Left and right iliac

Question 3

How else can the abdomen be separated?

Answer 3

Into 4 quadrants

Question 4

What are the 4 quadrants of the abdomen?

Answer 4

Left and right upper and lower quadrants

Question 5

What separates these quadrants?

Answer 5

Line down the centre and one horizontal at the belly button

Question 6

On the antero-lateral abdominal wall, what are some surface landmarks?

Answer 6

Linea alba - midline

Umbilicus - belly button

Costal margin - ribcage as it slopes

Xiphoid process

Iliac crest - lateral protrusion of hip bone

ASIS - Anterior protusion of hip bone

Pubic symphysis - pubic bone middle

Pubic tubercle - on both sides of the pubic symphysis

Question 7

How many layers of muscle are there on the lateral abdominal wall?

Answer 7

Three
Oblique
- external
- internal
- transversus abdominal

Question 8

What are the muscles on the anterior wall?

Answer 8

Paired vertical rectus abdominis - abs

Question 9

What are the muscles on the posterior wall?

Answer 9

Post-vertebral
- erector spinae

Psoas
Quadratus lumborum
Iliacus

Question 10

Where and what are the flank sheet muscles?

Answer 10

Muscles covering the lateral abdominal wall - which are?

Question 11

What is the function of the flank sheet muscles?

Answer 11

Compress the abdomen and increase intra-abdominal pressure -

Supports viscera - guard intestines

Flexes and rotates trunk

Question 12

What is the external oblique muscle attached to?

Answer 12

External surface of lower 8 ribs
- ORIGIN

HAS A FREE POSTERIOR BORDER

Attaches to - INSERTION

• xiphoid process
• linea alba
• pubic crest + tubercle
• anterior half of iliac crest

Muscle fibres are directed down and forward

Question 13

What is aponeurosis?

Answer 13

A sheet of white fibrous tissue that take the place of tendon in flat muscle, with a wide point of attachment.

The aponeuroses form the rectus sheath

Question 14

What is the internal oblique attached to?

Answer 14

Lateral
Thoracolumbar fascia
Iliac crest
Inguinal ligament

Medial
Lower 3 ribs
Xiphoid process
Rectus sheath

Fibres are downward and backward

Question 15

What is the transversus abdominis attached to?

Answer 15

Lateral

• Lower 6 costal cartilages
• Thoracolumbar fascia
• Iliac crest - anterior 3rd
• Inguinal ligament - lateral 3rd

Medial

• Xiphoid process
• Linea alba
• Symphysis pubis
• Conjoint tendon

Fibres are horizontal

Question 16

What is the rectus abdominis attached to?

Answer 16

Superior

• 5-7 costal cartilages
• Xiphoid process

Inferior

• Symphysis pubis
• Pubic crest

Fibres run longitudinally

Question 17

What forms the rectus sheath? What does it do?

Answer 17

Aponeurosis of 3 muscles. Covers rectus abdominis

Question 18

How is the rectus sheath divided?

Answer 18

Above umbilicus

• Internal oblique aponeuorsis ENCLOSES rectus abdominis
• External oblique is anterior to abdominis
• Internal is POSTERIOR

Below umbilicus
- All three aponeurotic layers sit anterior to the rectus muscle

Posterior rectus sheath ends at ARCUATE Line before umbilicus, after this it joins the transversalis fascia, anterior to the rectus abdominis

Question 19

What are the posterior abdominal wall muscles?

Answer 19

Psoas major

• hip and trunk flexor
• joins to the 5 lumbar vertebra

Quadratus lumborum
- stabilises 12th rib and lateral trunk flexor

Iliacus muscle
- hip joint flexor

Question 20

Nerve supply of the posterior abdominal wall

Answer 20

Subcostal

Iliohypogastric

Ilio-linguinal

Question 21

What is the nerve supply of the abdominal wall?

Answer 21

Segmental
 - External oblique
    - T7-11
 - Internal oblique and 
   transverse
    - T7-12 and L1
 - Rectus
    - T7-12 

Dermatomes at

• T7 - epigastrium
• T10 - umbilicus
• L1 - inguinal ligament

Question 22

What is the inguinal region?

Answer 22

Junction between abdominal wall and thigh

Question 23

Lymphatic drainage of the abdominal wall

Answer 23

None on the abdominal wall

Superficial
- go to the axiliiary lymph node

Deep
- mediastinal and external

Question 24

WHy is this area weak?

Answer 24

Muscles not directly attached to any structure

Question 25

What are the landmarks of inguinal region?

Answer 25

ASIS (anterior superior iliac spine) and pubic tubercle

Question 26

Why is this area weak?

Answer 26

Muscles not directly attached to any structure - ligament fills - thus weak

Question 27

What is the clinical and anatomical importance of this region?

Answer 27

C: Site of potential herniation - femoral or inguinal A: Site of structure entry and exit

Question 28

What is the inguinal canal used for?

Answer 28

The inguinal canal has an inherent weakness, allowing hernia formation M - testis and spermatic cord descend from abdomen into the scrotum via the canal - ilioingual nerve - genito-femoral nerve F - uterine ligament descends - ilion ingual nerve - genito-femoral nerve

Question 29

What is a hernia?

Answer 29

Where part of, or a whole organ/ tissue abnormally protudes through the wall of the structure containing the organ. Occurs if the deep inguinal ring is large enough for part of organ to 'pop' through

Question 30

Describe a hernia

Answer 30

Protrusion of peritoneum through defective abdominal wall, forming hernial sac Some organ is contained in the peritoneum Covered by skin - lump-like Requires - wall weaknesss - hernial sac - contents

Question 31

What is the structure of the inguinal canal?

Answer 31

Oblique passageway in the lwoer anterior abdominal wall 4cm long

Question 32

What are some facts about herniae in the groin

Answer 32

Inguinal > femoral In femoral, female > male - larger pelvis and hence space for herniation Most inguinal herniae are congenital

Question 33

What is the structure of the inguinal canal?

Answer 33

Oblique passageway in the lower anterior abdominal wall 4cm long, above medial half of inguinal ligament Deep ring 1.5cm above midpoint Superficial ring right above and medial to tubercle

Question 34

How many walls are there of the inguinal canal and what are they made of?

Answer 34

Anterior - external oblique aponeurosis - internal oblique for reinforcement - lateral 3rd Floor - rolled inferior edge of ext oblique - inguinal ligament Roof - arching fibres of both internal and external oblique muscles Posterior - transversalis fascia - medially conjoint tendon Made from the various muscles and ligament

Question 35

What is an inguinal hernia? | Compare the types

Answer 35

Direct - ACQUIRED - goes through Hesselbach's triangle - inguinal - posterior to superficial ring - always medial to inferior epigastric vessels - just goes through superficial ring - associated with chronic straining - doesn't go into scrotum Indirect - CONGENITAL - internal ring is LATERAL to inferior epigastric vessels - goes through deep ring THEN superficial - through to scrotum as it takes path that testes would - defective DEEP ring - dilation

Question 36

What are the layers of fat along the abdominal wall, superficial to deep?

Answer 36

Camper's fascia Scarpa's fascia Preparietal fat

Question 37

What happens if the abdominal aorta is blocked?

Answer 37

The superior and inferior epigastric arteries can anastomose, forming a bypass.

Question 38

How are the parietal and visceral peritoneum innervated?

Answer 38

Parietal - same as anterior abdominal wall Visceral - no innervation

Question 39

What is the femoral canal?

Answer 39

Canal beneath inguinal ligament containing lymph vessel, the femoral vein and artery pass lateral to it Vessels + canal = femoral sheath

Question 40

What is a conjoint tendon?

Answer 40

Lowest fibres of the internal oblique aponeurosis and transversus abdominis aponeurosis join, forming this tendon. Attaches medially to linea alba

Question 41

What is a femoral hernia?

Answer 41

Hernia via femoral canal Not as common as inguinal More common in women and elderly High incidence of obstruction and strangulation

Question 42

Where is the femoral canal located?

Answer 42

In relation to it: Superior - inguinal ligament Inferior - pectineus fascia Medial - lacunar (Gimbernat) ligament Lateral - femoral vein

Question 43

How are femoral herniae characterised?

Answer 43

Irreducible Hot and painful if strangulated *Distinguishable from inguinal as below and lateral to pubic tubercle*

Question 44

Where are inguinal hernias positioned?

Answer 44

Above and medial to pubic tubercle