Flashcards in Rectum/Anal Canal Deck (60)
The rectum is technically a part of what gastrointestinal structure?
Large intestine (between the sigmoid colon and the anal canal)
What is the rectosigmoid junction of the rectum and where is it located?
Upper limit of the rectum located at the middle of the sacrum
What is the anorectal junction and where is it located?
The lower limit of the rectum located at the upper border of the pelvic diaphragm
What muscles forms a sling around the rectum at the anorectal junction?
What is the rectal ampulla and where is it located?
Dilated terminal portion of the rectum located immediately above the pelvic diaphragm
How many transverse rectal folds are there?
Does the rectum have mesentery, omental appendices, or haustra?
Does the rectum have taeniae coli?
Yes, but it's spread out as a complete layer unlike the intestines
Peritoneum covers what parts of the upper third of the rectum?
Front and sides
Peritoneum covers what parts of the middle third of the rectum?
Peritoneum covers what parts of the lower third of the rectum?
There is no peritoneal covering here
The anal canal is between what two structures?
Pelvic diaphragm and anus
About how many anal columns lie in the anal canal?
What vascular structures do each anal column contain?
Small branch of the superior rectal artery and a small tributary of the superior rectal vein
What are the longitudinal folds of mucosa which lie in the upper half of the anal canal?
What are the crescent-shaped folds which connect the lower ends of the anal columns?
What are the recesses located between the anal valves and the wall of the anal canal?
What marks the lower limit of the anal valves around the circumference of the anal canal?
What is the bluish white zone located inferior to the pectinate line?
What is the distal termination of the anal canal where it meets the skin?
Which anal sphincter is under involuntary control?
Internal anal sphincter
Which anal sphincter is a continuation of the smooth muscle layer of the rectum below the pelvic diaphragm?
Internal anal sphincter
What are the three parts of the external anal sphincter?
Subcutaneous, superficial, and deep parts
What is the nerve supply of the external anal sphincter?
Nerve to external anal sphincter (S4)
What is the function of the external anal sphincter?
Closes anal orifice
Which anal sphincter is under voluntary control?
External anal sphincter
From where does the superior rectal artery arise?
Inferior mesenteric artery
From where does the middle rectal artery arise?
Internal iliac artery
From where does the inferior rectal artery arise?
Internal pudendal artery