Nerves & Vessels of the Abdomen

Question 1

The abdominal aorta divides into iliac arteries at

Answer 1

L4

Question 2

Anterior branches of the abdominal aorta supply

Answer 2

GIT & derivatives

Question 3

Lateral branches of the abdominal aorta supply

Answer 3

paired viscera (kidneys, adrenals, gonads)

Question 4

Posterior branches of the abdominal aorta supply

Answer 4

paired posterior structures, diaphragm, and posterior abdominal wall

Question 5

What are the 3 anterior (unpaired) branches of the AA?

Answer 5

celiac trunk (T12, upper border of pancreas)

superior mesenteric artery (L1, 1cm below celiac trunk)

inferior mesenteric artery (L3, inferior border of 3rd/hz part of duodenum)

Question 6

The coeliac trunk supplies

Answer 6

foregut derivatives:

abdominal oesophagus, stomach, liver, gallbladder, pancreas, spleen, duodenum up to major duodenal papilla

Question 7

What does the SMA supply?

Answer 7

midgut derivatives:

duodenum from major duodenal papilla, jejunum, ileum, appendix, caecum, ascending colon, most of the transverse colon up to near the splenic flexure

Question 8

What does the IMA supply?

Answer 8

hindgut derivatives:

transverse colon just proximal to splenic flexure, descending colon, sigmoid colon, rectum, and top of the anal canal

Question 9

What are the 3 branches of the celiac trunk?

Answer 9

splenic artery (L)

left gastric artery (L, superior and smaller than splenic)

common hepatic (R)

Question 10

What does the splenic artery supply?

Answer 10

main:

• spleen
• pancreas

gastric:

• short gastric arteries (L fundus & greater curvature)
• L gastroepiploic (greater curvature)

Question 11

What does the L gastric artery supply?

Answer 11

• oesophageal branches to cardio-oesophageal junction (abdominal oesophagus)
• lesser curvature of stomach

Question 12

What does the common hepatic artery supply?

Answer 12

• divides into proper hepatic artery (liver via portal triad)
  
  • divides into R & L hepatic arteries to the respective functional halves of the liver
  • RHA (normally, or PHA) gives off cystic artery to the gallbladder
  • gives off right gastric artery to lesser curvature of stomach
• and gastroduodenal artery
  
  • first part of duodenum (bleeds in peptic ulceration)
  • superior pancreaticoduodenal artery to head of pancreas
  • right gastroepiploic artery to greater curvature of stomach

Question 13

The SMA supplies

Answer 13

• inferior pancreaticoduodenal artery to distal duodenum

follows route of the mesentery (DJ flexure to ileocecal valve, across 3rd part of duodenum, aorta, IVC, lumbar VC, R psoas w/R ureter):

• L branches to jejunum and ileum
  
  • create vascular arcades and vasa recta
  • jejunum - few arcades, long vasa recta
  • ileum - multiple arcades, short vasa recta
• R branches to colon (colic arteries), contribute to marginal artery
  
  • iliocolic to beginning of colon
  • right colic to ascending colon
  • middle colic to transverse colon (up to where IMA takes over, just before splenic flexure)

Question 14

What does the IMA supply?

Answer 14

• heads down and L to L iliac fossa (LLQ)
• gives off colic branches:
  
  • left colic to rest of transverse colon & descending colon
  • sigmoid artery to the sigmoid colon
• then becomes superior rectal artery before passing into the pelvis

Question 15

The portal venous system drains

Answer 15

GIT (pancreas, gallbladder, spleen)

SMV + splenic vein (w/ IMV)

everything supplied by the coeliac trunk, SMA, and IMA except the liver

Question 16

What comprises the (hepatic) portal vein?

Answer 16

IMV drains into splenic vein

splenic vein joins SMV @ L2

forms portal vein behind neck of pancreas

Question 17

Structures supplied by lateral branches of the AA drain into

Answer 17

(adrenals, kidneys, gonads)

IVC (caval system)

Question 18

Structures supplied by the posterior branches of the AA drain into

Answer 18

(abdominal walls and diaphragm)

IVC/caval

Question 19

What causes portal hypertension?

Answer 19

fibrosis of liver (alcohol) + shrinking of hepatic sinusoids

impedes portal venous drainage into liver

Question 20

What are the five sites of portosystemic anastamoses?

Answer 20

• lower/abdominal oesophagus @ cardiac orifice (can tear w/vomiting)
  
  • tributaries of L gastric vein (portal) & tributaries of azygous vein (caval/systemic)
• inferior GIT/anus (haemorrhoids)
  
  • superior rectal veins (portal) & lower and inferior rectal veins (caval/systemic)
• anterior abdominal wall (caput medusa)
  
  • cutaneous veins (cava/systemic) & tributaries of portal vein (portal)
• posterior abdominal wall
  
  • retroperitoneal viscus (portal) w/back to posterior abdoiminal wall (caval/systemic)
• bare area of liver
  
  • liver (caval) on diaphragm (portal)

Question 21

Abdominal viscera are innervated by

Answer 21

ANS

Question 22

Foregut derivatives are innervated by

Answer 22

T6-T9

Question 23

Midgut derivatives are innervated by

Answer 23

T8-T12

Question 24

Hindgut derivatives are innervated by

Answer 24

T12-L2

Question 25

Preganglionic sympathetic fibres to the abdominal viscera are derived from

Answer 25

T6-L2

Question 26

Sympathetic ganglion to the abdomen cluster around

Answer 26

unpaired branches of AA and renal arteries

Question 27

Parasympathetic innervtation to the abdomen comes from

Answer 27

vagus (foregut and midgut), pelvic splanchnics (hindgut)

Question 28

Parasympathetic innervation to the foregut and midgut is by

Answer 28

vagus

Question 29

Parasympathetic innervation to the hindgut comes from

Answer 29

pelvic splanchnics (S2-4)

Question 30

Post-ganglionic sympathetic fibres travel to abdominal viscera via

Answer 30

arterial branches

Question 31

Visceral afferents of the abdomen run

Answer 31

* same spinal cord segment as sympathetic innervation **up to mid sigmoid colon** * same spinal cord segment as parasympathetic innervation **beyond the sigmoid colon**

Question 32

What structures refer pain to the midline of the anterior abdominal wall (dermatomes T6-L2)?

Answer 32

afferent fibres from unpaired abdominal viscera **proximal to the mid-sigmoid colon**

Question 33

What structures refer pain to the perineal region (dermatomes S2-4)?

Answer 33

afferetn fibres from **mid-sigmoid colon downward**

Question 34

Lymphatics of deep structures below the diaphragm drain into

Answer 34

pre-aortic and para-aortic lymph nodes

Question 35

Pre-aortic lymph nodes drain

Answer 35

anterior to the AA around the unpaired branches (celiac, SMA, IMA) and receive drainage from the structures they supply

Question 36

Para-aortic lymph nodes drain

Answer 36

R & L aorta, drain structures supplied by the sides and back of AA (posterior abdominal walls, kidneys, adrenals, gonads) + pelvis and lower limb

Question 37

What three lymphatics drain into the cisterna chyli?

Answer 37

intestinal lymph trunk from pre-aortic LNs R & L lumbar lymphatic trunks

Question 38

Where is the cisterna chyli?

Answer 38

adjacent to the aortic hiatus @ T12

Question 39

What is the course of the thoracic duct?

Answer 39

* cisterna chyli * traverse diaphragm w/AA thru crura @ T12 * posterior to oesophagus * crosses L at T4-T5 * empties at junction of left IJV and left subclavian vein

Question 40

The SMV drains

Answer 40

most of the gut from the 3rd part of the duodenum down to ~splenic flexure

Question 41

The IMV comes off the

Answer 41

splenic vein