Session 1 - the anterior abdominal wall and hernias

Question 1

How is the abdominal cavity bound posteriorly?

Answer 1

bounded by the lumbar vertebrae and the muscles lying lateral to them (- psoas (and iliacus) and quadratus lumborum)

Question 2

Which muscles are the most important expiratory muscles in deep, rapid or forced respiration?

Answer 2

the sheet muscles

Question 3

What are the serratus anterior and the lattisimus dorsi?

Answer 3

Other posterior muscles (although they are more important in thorax anatomy)

Serratus anterior –on the lateral wall of the thorax, with anterior origin and insertion along the medial border of the scapula; acts to pull the scapula forward and around the thorax

Lattisimus dorsi – large triangular muscle of the back, with origin in the thoracolumbar fascia, and insertion into the armpit

Question 4

What is the anterolateral abdominal wall composed of?

Answer 4

skin, fascia and four pairs of muscles; the external oblique, internal oblique, transversus abdominus and rectus abdominus

Question 5

Where is the pubic symphysis?

Answer 5

(a secondary cartilaginous joint located) between the left and right pubic bones near the midline of the body. It is located above any external genitalia and in front of the bladder

Question 6

Where is the pubic tubercle?

Answer 6

just next to the pubic symphysis

a prominent forward-projecting tubercle on the upper border of the medial portion of the superior ramus of the pubis

Question 7

What does ASIS stand for and where is it?

Answer 7

anterior superior iliac spine
found at the the anterior extremity of the iliac crest of the pelvis

NOTE: it provides attachment for the inguinal ligament, and the sartorius muscle

Question 8

What is the iliac crest?

Answer 8

the ilium is the largest bone of the pelvis

The crest of the ilium is the superior border of the wing of ilium and the superolateral margin of the greater pelvis.

Question 9

What s the iliac fossa?

Answer 9

a large, smooth, concave surface on the internal surface of the ilium

Question 10

What separates the abdominal and the pelvic cavities?

Answer 10

they are continuous, but the pelvic inlet (brim) separates the two

Question 11

What separates the thoracic and abdominal cavities?

Answer 11

the diaphragm

Question 12

What are the 4 lines that have to be drawn to split the abdomen into 9 regions?
What vertebral levels are the 2 horizontal lines/planes at?

Answer 12

• 2 mid-clavicular lines (right and left)
• subcostal plane (at L2)
• inter tubercular plane (at L5)

Question 13

What are the 9 regions of the abdomen?

from right to left

Answer 13

• right hypochondrium/hypochondriac region
• epigastric region
• left hypochondrium/hypochondriac region
• right flank/lumbar region
• umbilical region
• left flank/lumbar region
• right groin/iliac region
• hypogastric/supra pubic region
• left groin/iliac region

Question 14

What 2 lines are drawn to split the abdomen into 4 quadrants?

Answer 14

saggital plane

trans-umbilical plane

Question 15

What are the muscles of the anterior abdominal wall?

Answer 15

paired vertical rectus abdominis muscles with rectus sheath

Question 16

What are the muscles of the lateral abdominal wall?

Answer 16

3 flat sheet muscles:

• external oblique
• internal oblique
• transversus abdominis

Question 17

What are the muscles of the posterior abdominal wall?

Answer 17

• post vertebral muscles - erector spine group
• psoas (attached to the lower limb)
• quadratus lumborum
• iliacus muscles

Question 18

How do the 3 flank sheet muscles join at the front anteriorly?

Answer 18

NOTE: they are separate in the flanks

they continue anteriorly as aponeurotic sheaths and contribute to the rectus sheath

Question 19

What is the function of the 3 flank sheet muscles?

Answer 19

• compress the abdomen and increase intra-abdominal pressure to aid expiration, and evacuation of urine, faeces, parturition (childbirth), heavy lifting
• supports viscera - guards the intestines
• flex and rotate the trunk

Question 20

What is the external oblique attached to?

Answer 20

• external surface of lower 8th ribs
• it has a free posterior border
• it fans out to attach to xiphoid process, linea alba, pubic crest and the anterior half of the iliac crest

Question 21

What is the direction of the muscle fibres of the external oblique muscles?

Answer 21

infero-medially

anterior and inferior (downwards and forwards)

Question 22

What is the inguinal ligament?

Answer 22

a band running from the pubic tubercle to the anterior superior iliac spine

Question 23

What happens to the external oblique muscles towards the midline?

Answer 23

• the aponeurosis fuses medially with the the rectus sheath

- the lower aponeurotic edge is rolled inwards and forms the inguinal ligament (ASIS to pubic tubercle)

Question 24

Laterally, what does the internal oblique attach to?

Answer 24

• thoracolumbar fascia
• iliac crest
• inguinal ligament (lateral half)

Question 25

Medially, what does the internal oblique attach to?

Answer 25

- lower 3 ribs and costal cartilages - xiphoid process - rectus sheath - conjoint tendon

Question 26

What is the direction of the muscle fibres of the internal oblique muscles?

Answer 26

supero-medially | posterior and inferior (downwards and backwards)

Question 27

Laterally, what does the tranversus abdominis attach to?

Answer 27

- lower 6 costal cartilages - thoracolumbar fascia - iliac crest - inguinal ligament

Question 28

Medially, what does the tranversus abdominis attach to?

Answer 28

- xiphoid process - linea alba (rectus sheath) - symphysis pubis - conjoint tendon

Question 29

What is the direction of the muscle fibres of the tranversus abdominis?

Answer 29

horizontal (like a belt)

Question 30

Where does the neurovascular plane lie?

Answer 30

between the internal oblique and transversus abdominis muscle layers

Question 31

What is the rectus abdominis?

Answer 31

long strap of muscle of the anterior abdominal wall, enclosed in rectus sheath 2 heads NOTE: the muscle is divided into segments by tendinous intersections (3 on each side) which are attached to the anterior wall of the rectus sheath

Question 32

Where does the rectus abdominis attach superiorly?

Answer 32

- 5-7 costal cartilages | - xiphoid process

Question 33

Where does the rectus abdominis attach inferiorly?

Answer 33

- symphis pubis | - pubic crest

Question 34

What forms the rectus sheath?

Answer 34

the aponeuroses of the 3 flank muscles

Question 35

What is the structure of the rectus sheet around the rectus abdominis above the umbilicus?

Answer 35

- the internal oblique aponeurosis is split and encloses the rectus abdominis (the aponeurosis of the external oblique is in front and that of the transversus is behind the rectus muscle)

Question 36

What is the structure of the rectus sheet around the rectus abdominis below the umbilicus?

Answer 36

all 3 aponeurotic layers are anterior to the rectus muscle

Question 37

What is the linea alba?

Answer 37

where the rectus sheath meets at the midline

Question 38

The anterior wall of the sheath is complete from the _____ to the _____

Answer 38

from the xiphoid process and costal cartilages to the pubic symphysis and crest

Question 39

The posterior wall of the sheath is incomplete. Where does it stop?

Answer 39

at the arcuate line (just below the umbilicus)

Question 40

What is below the arcuate line?

Answer 40

the rectus abdominis muscle it is in contact with the transversalis fascia

Question 41

Which muscle is the most powerful floor of the spine?

Answer 41

rectus abdominis (external and internal oblique play an important role in this action)

Question 42

What are the posterior abdominal wall muscles?

Answer 42

- psoas major - a flexor of the hip and trunk | - quadratus lumborum - stabilises the 12th rib and a lateral flexor of the trunk

Question 43

What are the attachments of the psoas major?

Answer 43

bodies and discs of all 5 lumbar vertebrae and lesser trochanter of femur)

Question 44

What are the attachments of the quadratus lumborum?

Answer 44

lower border of the 12th rib and transverse process of the 5th lumbar vertebra and adjacent iliac crest

Question 45

What is the blood supply of the rectus muscle?

Answer 45

1- superior epigastric artery | 2- inferior epigastric artery

Question 46

How is blood supplied to the flank muscles?

Answer 46

``` (segmentally supplied) 1- intercostal arteries 7-11 2- subcostal artery 3- lumbar arteries 4- deep circumflex iliac arteries ```

Question 47

What is the venous drainage of the abdominal wall?

Answer 47

Depp veins bearing the same names (as the arteries) accompany the arteries

Question 48

What is the nerve supply of the abdominal wall?

Answer 48

motor nerves from T7-T11 and L1 | segmentally supplied

Question 49

What is the nervous supply of the external oblique muscles?

Answer 49

T7-T11

Question 50

What is the nervous supply of the internal oblique and transversus muscles?

Answer 50

T7-T12 and L1

Question 51

What is the nervous supply of the rectus?

Answer 51

T7-T12

Question 52

What are the dermatomes of the epigastrium, umbilicus and the inguinal ligament?

Answer 52

epigastrium - T7 umbilicus - T10 inguinal ligament - L1

Question 53

What is noticeable about lymph nodes and the abdominal wall?

Answer 53

there are NO lymph nodes in the abdominal wall

Question 54

Why do hernias commonly occur in the inguinal region?

Answer 54

because of the inherent weakness of the abdominal wall

Question 55

What are the 2 areas of inherent weakness in the groin?

Answer 55

1 - inguinal canal | 2 - femoral canal

Question 56

What are the common types of hernias in the inguinal region?

Answer 56

1- inguinal hernia - indirect and direct | 2 - femoral hernia

Question 57

What are the common types of hernias in the inguinal region?

Answer 57

1 - inguinal hernia - indirect and direct | 2 - femoral hernia

Question 58

Where is the acquired effect that causes a direct inguinal hernia?

Answer 58

posterior wall of the inguinal canal

Question 59

What vertebral level is the xiphoid process?

Answer 59

T10

Question 60

What is the difference between a tubercle and a symphysis?

Answer 60

Tubercle - a small rounded protrusion Symphysis - where two bones are joined The tubercle is just next to the symphysis.

Question 61

At what vertebral level is the transpyloric plane?

Answer 61

L1

Question 62

Describe the level of the subcostal plane

Answer 62

lower edge of the 10th costal cartilage | level of L3

Question 63

Describe the level of the supracristal plane

Answer 63

highest point on the iliac crest

Question 64

Describe the level of the inter-tubercular plane

Answer 64

between the tubercles of the iliac crests | level of L5

Question 65

Where is pain of the gut referred to?

Answer 65

foregut - epigastric region midgut - umbilical region handgun - pubic region

Question 66

What is meant by the foregut?

Answer 66

- Starts at the point the oesophagus pierces the diaphragm | - Ends just after the major duodenal papilla (second part of the duodenum)

Question 67

What is meant by the midgut?

Answer 67

- Begins just inferior to the major duodenal papilla | - Ends 2/3s of the way through the transverse colon

Question 68

What is meant by the hindgut?

Answer 68

- Starts 2/3s of the way through the transverse colon | - Ends mid-way through the anal canal

Question 69

What are the direct/immediate branches of the abdominal aorta that innervate the foregut, midgut and the hindgut?

Answer 69

foregut - celiac trunk midgut - superior mesenteric artery hindgut - inferior mesenteric artery

Question 70

What are the 3 parts of the abdominal wall?

Answer 70

anterior lateral posterior

Question 71

Give the layers of the anterior abdominal wall

Answer 71

- skin - superficial fascia - fatty (Camper's) and membranous (Scarpa's) - external oblique muscle - internal oblique muscle - tranversus abdominis - transversalis fascia (NOTE: well developed) - extraperitoneal fascia - parietal peritoneum

Question 72

Below the arcuate line, what is directly behind the rectus abdominis?

Answer 72

The transversalis fascia

Question 73

What is the linea semilunaris?

Answer 73

A curvilinear tendinous intersection found on either side of the rectus abdominis muscles

Question 74

What are the contents of the inguinal canal?

Answer 74

- The ilio-inguinal nerve (does not run in spermatic cord!) - Spermatic cord in men - Round ligament of the uterus in women

Question 75

What is a hernial sac made up of?

Answer 75

parietal peritoneum