GI 4 - Abdominal Wall + Hernias Flashcards
Name the 5 muscles which form the anterolateral abdominal wall:
1) External obliques
2) Internal obliques
3) Transverse abdominis
4) Rectus abdominis
5) Pyramidalis
What is the function of the anterolateral abdominal wall?
- Forms firm flexible wall
- Protects abdominal viscera
- Assists forced expiration
- Allows increased abdominal pressure for coughing/vomiting etc
Name the straight line down the middle of the rectus abdominis:
Linea alba
Where is the arcuate line? What is its significance?
1/3rd between the umbilicus and pubic symphysis
- Above this line = anterior and posterior shealth surrounding rectus abdominis
- Below this line = only anterior sheath
Why are most abdominal incisions performed through tendond/aponeurosis, not muscle?
- Tendons can be stitched back together to provide strength
- Muscles cannot be stitched - they shred
Where is the incision for an appendicetomy performed? What type of incision is it?
- McBurney’s point = 2/3rds from umbilicus to ASIS
- Grid-iron incision
Why is a C- section performed below the arcuate line?
No posterior sheath behind the rectus abdominus
= Better recovery
What is Ectopia cordis?
- Congenital
- Heart either partially or completely outside thorax
What is the presentation of a patent urachus?
Urine from umbilicus
What is the presentation of a patent vitelline duct?
Faeces from the umbilicus
What is exomphalos?
- Congenital
- Failure of abdominal contents to move into abdomen after development
- Viscera covered by peritoneum
What is gastroschisis?
Abdominal content’s do not move into abdomen after development
- Viscera not covered by peritoneum
What is the difference between exomphalos and gastroschisis?
Exomphalos - abdominal contents covered by peritoneum
Gastroschisis - abdominal contents not covered by peritoneum
What can cause visceral pain?
- Inflammation
- Ischaemia
- Stretch
Explain somatic referred pain:
Pain caused to proximal part of somatic nerve may be percieved in the distal dermatome of the nerve
What structures divide the peritoneal cavity into the greater and lesser sacs?
Greater omentum
Lesser omentum
What structure divides the greater omentum into the supra- and infra-colic compartments?
Transverse mesocolon
What GI structures are present in the supracolic compartment?
- Abdominal oesophagus
- Stomach
- Liver
- Spleen
- Upper part of duodenum
What GI structures are present in the infracolic compartments?
- Small intestine
- Ascending colon
- Descending colon
Name the structures which connect the supra- and infracolic compartments:
Left and right paracolic gutter’s
Name the structures in the free edge of the lesser omentum:
- Hepatic artery
- Hepatic portal vein
- Common bile duct
Name the extensions of the peritoneal membrane, in which fluid can collect:
- Rectouterine pouch (women)
- Vesicouterine pouch (women)
- Rectovesicle pouch (men)
- Paracolic gutters
- Hepatorenal pouch
Where are the main sites of potential weakness in the abdominal wall?
- Umbilical area
- Femoral cana
- Inguinal canal
- Site of previous abdominal surgery
What are the anterior and posterior walls of the inguinal canal?
Anterior = External obliques Posterior = Transversalis fascia + Conjoint tendon (medially)
What structures form the roof and floor of the inguinal canal?
Roof = Muscular arches + aponeuroses of internal oblique + transverse abdominus Floor = Inguinal ligament + lacunar ligament (medially)
Which structure lies at the midpoint of the inguinal ligament?
Deep inguinal ring
What structure lies at the mid-inguinal point?
Femoral artery
What is the length of the inguinal canal?
~ 4 cm
Define hernia:
Protrusion of organ through a cavity wall of which it is normally contained
What is the difference between direct and indirect hernias, in regards to their origin?
Direct = originate medial to inferior epigastric vessels Indirect = originate lateral to inferior epigastric vessels
