Week 12: Abdomen workshop

Question 1

What are the boundaries of the inguinal canal? (Floor, roof, anterior and posterior wall)

Answer 1

Floor: Inguinal ligament
Roof: Arching fibres of internal oblique and transversus abdominus
Ant wall: External oblique reinforced laterally by internal oblique
Post. wall: Fascia transversalis reinforced medially by the conjoined tendon

Question 2

What are the contents of the inguinal canal?

Answer 2

Ilioinguinal nerve

Male: Spermatic cord

Female: Round ligament

Question 3

What can predispose someone to inguinal hernias?

Answer 3

Weak musculature, straining (raised intra-abdominal pressure)

Question 4

What structures lie anterior to psoas and quadratus lumborum?

Answer 4

Psoas: genitofemoral nerve, ureters, gonadal vessels

Quad: iliohypogastric and ilioinguinal nerves, kidneys

Question 5

What is the relationship of the thoracolumbar fascia to the anterior and posterior abdominal wall muscles?

Answer 5

3 layers of tough fibrous tissue enclose 2 muscular compartments (erector spinae, quadratus lumborum). The lateral border gives origin to transversus abdominus and internal oblique

Question 6

What is a psoas abscess?

Answer 6

A tuberculous abscess in the lumbar region that tends to spread from the vertebra, into the psoas sheath and then tracks back beneath the inguinal ligament into the thigh

Question 7

Where do iliohypogastric and ilioinguinal nerves emerge from?

Answer 7

Lateral border of psoas on quadratus lumborum entering the neurovascular plane of the anterolateral abdominal wall

(L1)

Question 8

What do iliohypogastric and ilioinguinal nerves supply?

Answer 8

Skin over inguinal region, provide motor supply for internal oblique/transversus (forming the roof)

Ilioinguinal also supplies skin of scrotum/labia

Question 9

Where does the genitofermoral nerve emerge from?

Answer 9

Onto anterior psoas, genital and femoral part

Question 10

What does the genitofemoral nerve supply?

Answer 10

L1: skin over fermoral triangle
L2: spermatic cord

Question 11

What is the nerve supply for the visceral and parietal peritoneum?

Answer 11

Parietal: via body wall, somatic nerves/parietal vessles

Visceral: same as the viscera, visceral nerves and vessels

Question 12

What are the 4 major sites of portosystemic anatstamoses?

Answer 12

Lower end of oesophagus
Upper end of anal canal
Periumbilical region (caput medusae)
Bare areas of liver and secondarily retroperitoneal viscera

Question 13

Why are there alternate routes of flow available with the portal system?

Answer 13

It is valveless

Question 14

What veins does the oesophagus, anal canal and anterior wall drain via?

Answer 14

Oesophagus: left gastric vein
Anal canal: upper: superior rectal (from IMV), lower: internal iliac veins
Ant ab wall: free edge of the falciform ligament to portal vein

Question 15

Where is the transpyloric plane? What is it?

Answer 15

L1, passing through where rectus sheath meets costal margin

Question 16

What is in the transpyloric plane from R to L?

Answer 16

Gallbladder (funds)
Hilum R kidney (below)
Pylorus/duodenum
Neck of pancreas
End of deuodenum
SMA origin
Hilum L kidney (above)

Question 17

Where does the liver sit?

Answer 17

Upper: between nipples
Lower: beneath costal margin (on deep inspiration)

Question 18

What is McBurney’s point? (what is it useful for?)

Answer 18

1/3rd of way along R ASIS to umbilicus

-marks base of appendix (appendectomy incision)

Question 19

How does the contrast get into the biliary tree when doing an endoscopic retrograde cholangiopancreatogram (ERCP)?

Answer 19

Through ampulla of Vater (hepatopancreatic amupulla/duct), the accessory duct does not fill

(Vater: union of pancreatic/common bile duct)