Anal Anatomy and Cancer Flashcards
We have 2 anal sphincters. For each of the 2 sphincters state if
striated or not
Voluntary or not
Nerve supply
Internal sphincter: Non-striated, Involuntary, supplied by autonomic nerves
External Sphincter: Striated, voluntary, supplied pudendal nerve
The external sphincter is fused with another muscle which is important for maintaining the anorectal angle.
What is the muscle
What is the importance of maintaining the anorectal angle
Puborectalis Muscle
This muscle supports the anorectal angle which is necessary for continence
The anal canal is divided into the
Upper X/3
Lower X/3
What is X?
What epithelial cells are in each?
What is the arterial supply?
What is the lymphatic drainage?
Upper 2/3 columnar epithelium
Supplied by the superior rectal artery (from inf. mesenteric)
Drains to the internal iliac LN
Lower 1/3 squamous epithelium
Supplied by the Inferior rectal artery (from pudendal artery) - Just like pudendal nerve supplies the external sphincter.
Drainage to the Inguinal LN (important for SCC of anal canal)
Is anal cancer more common in men or women?
Women
What is the stereotypical patient for anal cancer?
Old female smoker with multiple sexual partners
What Virus and top 3 subtypes are the strongest RF for anal cancer
HPV 16, 18, and 1
With regards to anal cancer HPV 1 causes the formation of… (medical word)
Anorectal Condyloma
List the RF for Anal cancer
What are the 2 most common types of Anal cancer
SCC
Adenocarcinoma
There are 2 categories of anal cancer. Those that arise from the anal canal mucosa (this chapter) and those that arise at the perianal margin. What separates these?
Above and below the dentate line (2/3 above, 1/3 below)
What is Bowen’s disease?
AIN III => progression to carcinoma
(anal intraepithelial neoplasia)
Discuss the pathophysiology of Anal cancer
What is the LN drainage and hence lymphatic spread of Anal cancer?
Patients with anal cancer present with pain, altered bowel habit, rectal bleeding, tenesmus and a rectal mass on DRE. What investigations will you perform before starting treatment?
Same as rectal (in CRC) + examination under anaesthesia instead of colonoscopy
Treatment is based on stage of the disease.
T1N0:
T2,3,4 N0:
N1/M1:
go ahead
