lecture 9 - Lower GIT

Question 1

Lower GIT

Answer 1

1. Caecum & appendix
2. Colon
3. Rectum
4. Anal canal

Question 2

Caecum:

Answer 2

• Most proximal part of the large intestine
• Found Right Iliac fossa or right lower quadrant
• Found inf to ileocecal junction

Question 3

Appendix:

Answer 3

– Found in Right Iliac fossa or right lower quadrant – McBurney’s point
– attached to Posteromedial aspect of caecum
– Inferior to ileocaecal junction
– Retrocaecal BUT position is variable

Question 4

Appendix might be found at McBurney’s point (on R side)
McBurney’s point:

Answer 4

• Line from the anterior superior iliac spine to the umbilicus
• 1/3rd from lateral
• Base of appendix attached ceacum
• Surgical access

Question 5

Appendix location is highly variable, depends on the relationship with the ileum, cecum or pelvis

Answer 5

• Most common location is retrocecal (43.5%)
• 24.4% cases it is subcecal
  Rule: follow tenia coli
• Pre- and post ileal
• Sub-, retro- or paracecal
• Sub hepatic
• Retro colic
• Pelvic

Question 6

caecum features

Answer 6

– NO mesentery = intraperitoneal
- Sup continuous with the ascending colon
- Between cecum and ileum = ileocaecal valve
> this prevents reflux of the contents back into the ileum during peristalsis
– Ileocaecal lips (frenula) surround ileal orifice
– Ileal papilla
– Bound to lateral abdominal wall by caecal folds
– Enveloped by peritoneum

Question 7

Appendix features

Answer 7

• – Blind intestinal diverticulum
• Originates in posterior medial aspect of the cecum
• – supported by Short triangular mesentery (mesoappendix)
• Contains large amount of lymphoid tissue – not thought to have any vital functions though

Question 8

blood supply of caecum

Answer 8

Arterial supply:
derived from the embryological midgut, thus vascular supply is via the branches of the sup mesenteric vessels –> Ileocolic artery (branch of SMA)

venous supply:
Ileocolic vein (to SMV)

Question 9

blood supply of appendix

Answer 9

Arterial supply:
Appendicular artery (from ileocolic artery)

venous:
Appendix 1st drains into appendicular vein  ileocolic vein  Sup mesenteric vein

Question 10

Caecum & appendix: Lymphatics

Answer 10

• Lymph nodes of mesoappendix
• Ileocolic nodes
• Efferent lymphatic vessels then pass to the Superior mesenteric nodes

Question 11

Caecum & appendix: innervation

Answer 11

• Sympathetic: Sup mesenteric plexus
• Parasympathetic: Vagus ne

Question 12