Sigmoid colon :-
Length:-25-38 cm .Location :- infront of pelvic brim.as a continuation of descendingcolon ..below is continuous with rectum infront of 3rd sacral vertebrae.
Note :- it is a mobile structure.
**What is the direction of curve of sigmoid colon ?Is usually to the right of midline.
Note :- sigmoid colon is retroper???itoneal organ.
Attached tom post .abdominal wall by sigmoid mesocolon.Relations:-
1)ant:-a)in male :-urinary bladder
b)in female :-the post.surface of uterus & upper part of vagina.
2)post:-rectum & sacrum.lower coils of ileum.
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Rectum :-
Length:-13cm
Location :-it follows the curve of sacrum & coccyxbegins infront of 3rd sacral vertebrae.
Note :- rectum doesnt contain appendicies epiploica.
Dont have taienia colli.
Rectum is devoid of mesentery.
Not sacculated .
Extension :- begins as continuation of sigmoid colon ..passes downward to be continuous with anal canal.
Note :- at junction of rectum with anal canal ,there will be anorectal angle
**define ampulla ?Is the dilated part of rectum .it is the lower end of rectum.
**describe mucous membrane of rectum?
It forms semicircular folds that are permenant three to four in number called transverse rectal folds.in the left 2..in right 1.Note :- the rectum is having the curvature to delay stool expelling.
Relations :-ant :- in male =the coils of ileum & sigmoid colon occupy the rectovesical pouch ..also is related to prostate ,vas deferens....in female :- the post surface of vagina.& coils of ileum ,sigmoid colon within Douglas pouch.
Post :-the sacrum & coccyx.
Muscles :- piriformis ,coccygyeus,levator ani muscles,sacral lexus & sympathetic trunk .((((((((((((((((((((((
Blood supply :-
1)sup.rectal artery :- branch from inf.mesenteric artery.2)middle rectal artery :- branch from int.iliac artery.
3)inf.rectal artery:- branch from int.pudendal artery.
Veins :- corresponds to the arteries ...union between them is called (portal rectal anastmosis).
Lymph nodes:- pararectal lymph nodes.
Nerve supply :- from inf.hypogastric plexus.,,,it is only sensitive to stretch.Sympa & parasympa