Abdomen I: Abdominal wall and Cavity

Question 1

What are the boundaries of the abdomen

Answer 1

superior: diaphragm (5th intercostal space)
posterior: lumbar vertebrae and quadratus lumborum muscle
anterolateral: abdominal muscles
inferior: pelvic brim

Question 2

What are the functions of the abdomen?

Answer 2

1. to protect the abdominal viscera: digestive organs, kidneys, spleen

Question 3

What are the functions of the abdominal muscles?

Answer 3

1. protection of abdominal contents
2. movement of the trunk
3. compression of the abdominal visceral
4. expansion of abdominal cavity
5. expelling abdominal contents (mictruition, defacation, parturition, vomiting) - increase intra-abdominal pressure

Question 4

What separates the four abdominal quadrants?

Answer 4

1. the transumbilical plane (horizontal at the umbilicus)
2. the median plane (vertical from the pubic symphysis)

RUQ, LUQ, RLQ, LLQ

Question 5

how many abdominal quadrants are there? How many abdominal regions are there?

Answer 5

quadrants: 4
regions: 9

Question 6

What lines separate the abdominal regions?

Answer 6

Vertically: midclavicular plane that runs through the midinguinal point

Horizontally:

a) subcostal plane (under 10th costal cartilage)
b) transtubercular plane at the anterior superior ishial spine

Question 7

List the layers of the anterolateral abdominal wall from superficial to deep.

Answer 7

skin –> superficial fascia –> deep fascia –> muscle –> transversalis fascia –> extra peritoneal fat/fascia –> peritoneum

Question 8

List the muscles of the anterolateral abdominal wall

Answer 8

1. rectus abdominus
2. external oblique
3. internal oblique
4. transversus abdominus

Question 9

what are the muscles of the posterior abdominal wall?

Answer 9

1. quadratus lumborum

2. iliopsoas - psoas major + iliacus

Question 10

what is the innervation of the anterolateral abdominal wall?

Answer 10

Anterior rami of spinal nerves T7 to L1.

1. Intercostal nerves T7-T11; 2. subcostal nerve T12 and 3. iliohypogastric & ilioinguinal nerve (L1)

Question 11

What arteries supply the anterolateral abdominal wall?

Answer 11

from internal thoracic vessels:

1. superior epigastric artery
2. branches of musculophrenic vessels

from external iliac

3. inferior epigastric artery
4. deep circumflex iliac artery

Question 12

What important structure develops in the abdominal cavity and descends down into the scrotum through the inguinal canal?

Answer 12

testis

Question 13

is the inguinal canal found in males or females?

Answer 13

both

Question 14

What is the inguinal canal

Answer 14

• It is a 4cm long tube-like space within the lower part of the anterior abdominal wall
• it beings at the deep inguinal ring and ends at the superficial inguinal ring

Question 15

describe the boundaries of the inguinal canal

Answer 15

floor: inguinal ligament
anterior wall: external oblique aponeurosis
roof: arched fibres of internal oblique and transverses abdominis muscles
posterior wall: transversalis fascia (laterally) and conjoint tendon (medially)

Question 16

what is inside the inguinal canal in males?

Answer 16

1. the spermatic cord and its coverings + the ilioinguinal nerve

in the spermatic cord:

a) vas deferens
b) testicular artery and vein
c) genital branch of genitofemoral nerve
d) lymphatic vessels

Question 17

what is found in the inguinal canal in females?

Answer 17

1. round ligament of the uterus

2. the ilioinguinal nerve

Question 18

What does the parietal peritoneum cover?

Answer 18

lines the abdominal wall

Question 19

what does the visceral peritoneum cover?

Answer 19

covers the viscera

Question 20

What are the 2 main divisions of the peritoneal cavity?

Answer 20

1. greater sac: largest part of the cavity

2. lesser sac: smaller part, situated posterior to the stomach and liver

Question 21

Where does the greater omentum attach?

Answer 21

stomach and transverse colon

Question 22

What is the purpose of the greater omentum?

Answer 22

to prevent organs from sticking to the anterior abdominal wall

Question 23

What are the different parts of the greater omentum?

Answer 23

1. gastrophrenic ligament
2. gastrosplenic ligament
3. gastrocolic ligament

Question 24

what are the different parts of the lesser omentum?

Answer 24

1. hepatogastric ligament

2. hepatoduodenal ligament

Question 25

what is another name for the lesser sac?

Answer 25

omental bursa

Question 26

where is the lesser sac found?

Answer 26

It is a pounch dorsal to the stomach

Question 27

What is the epiploic foramen?

Answer 27

it is an opening from the greater sac to the lesser sac beside the hepatoduodenal ligament

Question 28

What is important about the hepatoduodenal ligament?

Answer 28

it contains important blood and bold vessels going to and from the liver

Question 29

what ligament attaches the liver to the anterior abdominal wall?

Answer 29

the falciform ligament

Question 30

What is the mesentery?

Answer 30

• It is a double layer of peritoneum that attaches organs to the posterior abdominal wall (mainly small intestine) that contains blood/lymph, vessels, fat, nerves
• makes the organs mobile

Question 31

what does retroperitoneal mean in terms of retroperitoneal organs?

Answer 31

retroperitoneal organs lie between the parietal peritoneum and the posterior abdominal wall

Question 32

what does intraperitoneal mean?

Answer 32

intraperitoneal organs are covered by visceral peritoneum

Question 33

What are the retroperitoneal organs?

• stomach
• spleen
• liver & gallbladder
• small intestine (jejunum, ileum, and small part of duodenum
• large intestine (transverse colon, sigmoid colon)

Answer 33

• Kindeys & suprarenal glands
• pancreas
• most of the duodenum
• large intestine (ascending and descending colon)