rectum Flashcards
(13 cards)
1
Q
Location of the rectum
A
- Begins at S3 (continues from sigmoid colon) - Ends at anal canal (at pelvic diaphragm).
2
Q
Direction of the rectum
A
- Descends along sacral curvature - Turns posteriorly at rectosigmoid junction - Turns anteriorly at anorectal junction.
3
Q
Anteroposterior curvatures
A
- Sacral flexure (follows sacrum) - Perineal flexure (anterior turn at anorectal junction).
4
Q
Lateral curvatures
A
- Upper: Convex right - Middle: Convex left - Lower: Convex right.
5
Q
Arterial supply
A
- Superior rectal (from IMA) - Middle rectal (from internal iliac) - Inferior rectal (from internal pudendal).
6
Q
Venous drainage
A
- Superior rectal → IMV → portal system - Middle/inferior rectal → internal iliac → caval system (portocaval anastomosis).
7
Q
Valves of the rectum
A
- Houston’s valves (3 transverse folds): - Upper: Near rectosigmoid junction - Middle: Largest (at rectal ampulla) - Lower: Near anorectal junction.
8
Q
Clinical significance of valves
A
- Prevent fecal incontinence - Middle valve marks peritoneal reflection (anteriorly).
9
Q
Supports of the rectum
A
- Pelvic floor muscles (levator ani) - Ligaments: Lateral (rectal stalks), posterior (rectosacral fascia).
10
Q
Peritoneal relations
A
- Upper 1/3: Covered anteriorly/laterally - Middle 1/3: Covered only anteriorly - Lower 1/3: Extraperitoneal.
11
Q
Posterior relations
A
- Sacrum & coccyx - Piriformis muscle - Sacral plexus - Middle sacral vessels.
12
Q
Anterior relations (Male)
A
- Bladder - Seminal vesicles - Prostate - Ductus deferens.
13
Q
Anterior relations (Female)
A
- Uterus - Vagina - Rectouterine pouch (of Douglas).
