Large bowel (341-352)

Question 1

How would you distinguish the small bowel from the caecum?;

Answer 1

1. Ileo-caecal junction.
2. Small bowel 3cm diameter, Caecum 6cm diameter.
3. Small bowel fully mobile whereas Caecum is more fixed.

Question 2

How would you distinguish the caecum from the ascending colon?;

Answer 2

Caecum has no omental appendage whereas ascending colon does.

Question 3

How would you distinguish the sigmoid colon from the rectum?;

Answer 3

Sigmoid colon is mobile unlike rectum which is fixed. Sigmoid colon will have omental (epiploic) appendage. Upper rectum intraperitonieal & lower rectum extraperitoneal. Sigmoid intraperitonieal.

Question 4

What are characteristic features of the large bowel?;

Answer 4

Taenae coli. Haustrum of colon. Omental appendage.

Question 5

Describe the blood supply to the rectum?;

Answer 5

Superior rectal artery (branch of IMA). Middle rectal artery (branch of internal iliac artery). Inferior rectal artery (branch of pudendal artery).

Question 6

Describe the lymphatic drainage of the rectum;

Answer 6

Follow blood vessels. Superior one - IMA nodes. Middle zone - internal iliac artery. Lower zone - superficial inguinal / internal iliac nodes.

Question 7

What is the epithelium of the anal canal?;

Answer 7

Above denate line- simple columnar epithelium. Below denate line- stratified squamous epithelium.

Question 8

What is the lymphatic drainage of the anal canal?;

Answer 8

Above dentate line- internal iliac lymph nodes. Below dentate line- superficial inguinal nodes.

Question 9

Describe the sphincter mechansism of the anal canal?;

Answer 9

Internal sphincter- autonomic nerves. External sphincter- pudenal nerves.

Question 10

How would you classify haemorrhoids?;

Answer 10

Grade 1- remain in rectum (protudes but does not prolapse). Grade 2- prolapses through anus on defecation but spontaneously reduce. Grade 3- prolaps through anus on defecation but require digital reduction. Grade 4- remain persistently prolapsed (irreducible). Grades 1 & 2 internal. Grades 3 & 4 external. (Three vascular cushions in anus positioned at the 3, 7 and 11 o’clock postitions)

Question 11

What are the treatment options for haemorrhoids?;

Answer 11

Ix- proctosocpy +/- flexi sig or colonscopy and FBC + clotting to ix PR bleeding and confirm diagnosis. Mx for asymptomatic Grade 1 & 2- usually conservative mx- lifestyle, diet (fibre), laxative, topical analgesia. Mx for symptomatic Grade 1 & 2- rubber band ligation, sclerotherapy. Mx symtomatic Grade 3 & 4- haemorrhoidal artery ligation (haemorrhoid infarcts and falls off), Haemorrhoidectomy (open or closed), rectopexy.

Question 12

What are the treatment options for anal fissures?;

Answer 12

Medical mx- analgesia, diet (fibre), laxatives (stool softners such as movicol), topical anaesthetic such as lidocaine, GTN or diltiazem cream. Surgical mx (chronic fissue >6/52)- botox injection (into internal anal sphincter), lateral sphincterotomy (last resort due to high risk incontinence)