Abdo Anatomy- Intro

Question 1

Where does the abdominal cavity extend from?

Answer 1

Diaphragm to the pelvic girdle.

Question 2

Horizontal planes:

Vertebral levels

Answer 2

Transpyloric plane: Through pylorus L1
Subcostal plane: below ribs, L3
Supracristal: L4, highest point of pelvis
Transtubercular: L5

Question 3

Which planes divide the abdomen into 9 regions?

Answer 3

Mid-clavicular
Subcostal (L3)
Transtubercular (L5)

Question 4

What are the attachments and function of the rectus abdominis?

Answer 4

Flexes the vertebral column
Stabilises pelvis during walking
Separates down linea alba during pregnancy
Compresses abdominal contents

Crest of pubis to xiphoid process and costal cartilage 5-7

Question 5

What does the lower portion of the external oblique attach to? What does this form?

Answer 5

ASIS to pubic tubercle

Inguinal ligament

Question 6

Rectus Abdominis:
Location
Innervation
Functions

Answer 6

Crest of pubis-> xiphoid process and CC of ribs 5-7
T7-T11 thoracoabdominal nerves
Compresses abdominal viscera, stabilises pelvis during walking

Question 7

External oblique:
Location
Innervation
Functions

Answer 7

Ribs -> iliac crest, pubic tubercle & linea alba
T7-T11 thoracoabdominal and subcostal T12 nerves
Contralateral rotation of the torso

Question 8

Internal oblique:
Location
Innervation
Functions

Answer 8

Inguinal ligament, iliac crest and lumbodorsal fascia -> ribs
T7-T11 thoracoabdominal and subcostal T12 nerves
Unilateral contraction = ipsilateral rotation of torso
Bilateral contraction = compression of abdomen

Question 9

Transversus abdominis:
Location
Function
Innervation

Answer 9

Inguinal ligament, CC, iliac crest & thoracolumbar fascia -> conjoint tendon, linea alba, xiphoid process and pubic crest
Compression of abdo
T7-11 thoracoabdominal , subcostal T12

Question 10

What is the rectus sheath? Where is it?

Answer 10

Formed by the aponeuroses of the flat abdominal wall muscles and the transversalis fascia.
Above the arcuate line surrounds the rectus abdominis
Below the arcuate line sits anterior to the rectus abdominis.

Question 11

What does the rectus sheath contain?

Answer 11

Inferior epigastric artery and vein

Question 12

What is the blood supply to the abdominal wall?

Answer 12

Superior and inferior epigastric arteries: meet in the rectus sheath, unite the subclavian and external iliac arteries which forms a shunt route if aorta is narrowed.

Question 13

What is the lymphatic drainage of the abdominal wall?

Answer 13

Follows quadrants
Upper quadrants: Axillary ipsilateral side
Lower quadrants: inguinal lymph nodes ipsilateral and contralateral sides

Question 14

Where is the gut tube located?

Answer 14

Peritoneal cavity, wrapped in peritoneum

Question 15

What structures are intraperitoneal?

Answer 15

Spleen
Liver
Stomach

Question 16

What structures are retroperitoneal?

Answer 16

S- Suprarenal (adrenal) glands
A- Aorta
D- Duodenum
P- Pancreas (head and body)
U- Ureters
C- Colon (ascending and descending)
K- Kidneys
E- oEsopagus
R- Rectum

Question 17

What suspends the gut tube from the posterior abdominal wall?

Answer 17

Mesentery

Question 18

What is a secondary retroperitoneal structure?

Answer 18

Intraperitoneal structure that later becomes retroperitoneal

Question 19

What are the visceral and parietal peritoneum? What are they sensitive to?

Answer 19

Visceral peritoneum: covers organ: insensitive to burning/cutting. Sensitive to stretch, inflammation, chemical change, hypoxia.

Parietal peritoneum: Covers inside of body wall, somatic innervation: highly sensitive to many stimuli.

Question 20

What is the mesentery?

Answer 20

Double layered fold of peritoneum

Question 21

What is the blood supply to the gut tube? What are the vertebral levels?

Answer 21

Foregut: Coeliac Trunk, T12

Midgut: Superior mesenteric artery, L1

Hindgut: Inferior mesenteric artery, L3

Question 22

What are the boundaries of the foregut, midgut and hindgut?

Answer 22

Foregut: Lower oesophagus to major duodenal papilla (between sections 2 and 3 of duodenum)

Midgut: Major duodenal papilla to 2/3 along transverse colon

Hindgut: 23 along transverse colon to upper anal canal

Question 23

Where does the foregut refer pain to?

Answer 23

Epigastric region (T5-T9 spinal nerves)

Question 24

Where does the midgut refer pain to?

Answer 24

Umbilical region (T10-T11 spinal nerves)

Question 25

Where does the hindgut refer pain to?

Answer 25

Pubic region (T12-L1 spinal nerves)

Question 26

Explain the mechanism of visceral pain referral

Answer 26

Visceral and somatic sensory nerves enter the spinal cord together and travel in the same spinal tracts.
The brain confuses location of origin, assumes pain is from dermatomal area.