Lecture 11 - Alimentary 3 Flashcards
Where does the rectum extend between?
S3 to pelvic diaphragm
The ampulla is the superior more narrow section, true or false?
False
How do you distinguish the rectum from the sigmoid colon? (5)
- No mesentery
- Retroperitoneal
- No sacculations
- No epiploic appendices
- No taenia
What is the special feature of the mucous in the wall of the rectum?
The submucosa contains a venous plexus linking superior and inferior rectal veins
What are the 2 planes of curvatures in the rectum?
- Anterior to posterior - follows the curve of the sacrum (sacral flexure)
- Laterall - Right to Left (largest) then Right
Where and what kind of folds are temporary in the rectum?
Longitudinal and in the ampulla
What are the features of the permanent folds in the rectum? (4)
- Variable in number
- Size and shape but commonly three
- Include mucosa, submucosa and a variable amount of external muscle
- The folds produce lateral folds?
Which permanent fold of the rectum is the largest and most constant
The middle fold
Where is the middle fold located? Where are the other folds located in relation to this?
Immediately above ampulla and roughly at the level of the rectovesicular/uterine pouch. The others are 4cm above or below
The peritoneum is loosely attached to the rectum true or false?
True
Where is the peritoneum attached on the rectum (3 points)?
Upper 1/3 - anterior and sides
Middle 1/3 - anterior only
Lower 1/3 - no periteoneum
What does the reflection of the middle 1/3 attachment of the peritoneum form?
The rectovesicular pouch
What are the posterior relations of the rectum (3)?
Sacrum, coccyx and pelvic diaphragm
What are the lateral relations of the rectum (3)?
Sigmoid colon, ileum, pelvic diaphragm
What are the anterior relations of the rectum in the male? (5)
Rectovesicular pouch, base of bladder, ductus deferens, prostate, seminal vesicle
What are the anterior relations of the rectum in females? (3)
Rectovesicular pouch (Pouch of Douglas), uterus and vagina
How does the anal canal sit/run
Using it’s legs hah
Postero-inferiorly through the pelvic diaphragm (coccygeus) to anus
What is the sling of skeletal muscle at the rectoanal junction called?
Puborectalis
How many columns are in the upper part of the rectum
6-10
How are the lower ends of the columns joined?
Transverse folds or valves
What is the space between columns called?
Sinuses
What is the line of valves in the rectum called?
Pectinate or dentate or mucocutaneous line
Where is the cloacal membrane?
At the pectinate/dentate/mucocutaneous line
What is the cloacal membrane? (2)
Junction of mucosa with skin with its own blood supply
How do the different layers of mucosa change in the rectum?
From epithelium to simple columnar than a transitional zone or non keratinised stratified squamous epithelium
There are sphincters over the entire length of the anal canal true or false?
True
Where are the internal and external sphincters?
Upper 2/3 and lower 2/3 of the anal canal
What do the internal sphincters consist of?
Thickened circular layer of external smooth muscle which stop at the junction of skin