Anal Canal: Supply And Clinical

Question 1

Arterial supply

Answer 1

1. Upper cloacal part:
   Superior rectal artery
   (inferior mesenteric artery continuation)
2. Lower proctodeal part:
   Inferior rectal artery (branch from internal pudendal artery)

Question 2

Venous drainage

Answer 2

1. Superior rectal vein:
   Ends in inferior mesenteric vein (portal)
   Drains cloacal part
2. Inferior rectal vein:
   Ends in internal pudendal vein
   (systemic)
   Drains anal canal proctodeal part
   N.B.: Both veins communicate together (portosystemic anastomosis)

Question 3

Lymph drainage

Answer 3

1. Upper 1/2: internal iliac nodes
2. Lower 1/2: superficial inguinal nodes

Question 4

Piles (haemorrhoids)

Answer 4

2 types:
1. External
2. Internal

Question 5

External piles

Answer 5

Varocities (dilatation) of inferior rectal vein tributaries as they run lateral from anal margin being covered by skin

Question 6

Internal piles

Answer 6

1. Varicosities of superior rectal vein tributaries (internal rectal venous plexus)
2. Covered by mucous membrane
3. Occurs mainly in the 3 anal columns veins situated at 3, 7, 11 o’clock positions

Question 7

Anal valves

Answer 7

May be torn by hard feces producing anal fissure which is very painful because it involves lower sensitive dermal part of anal canal

Question 8

Anal glands

Answer 8

May be infected producing abscess

Question 9

Perianal abscesses

Answer 9

May be:
1. Submucosal
2. Subcuateneous
or
3. Ischiorectal abscesses

Question 10

PR examination

Answer 10

Finger introduced through anal orifice to palpate different
structures related to rectum and anal canal:
1. Anterior:
In male: Prostate and seminal vesicle
In female: vagina, posterior fornix, uterus cervix, perineal body and ovaries
2. Posterior: Anorectal body and coccyx (in both sexes)
3. On either side: Ischiorectal fossa and ischial spines (in both sexes)