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Flashcards in Rectum Deck (25):
1

How long is the rectum

15cm

2

What vertebral level does the rectosigmoid junction occur at

S3

3

Describe peritoneal covering of the rectum

First third - peritoneum over anterior and lateral surfaces
Middle third - peritoneum over anterior surface
Last third - subperitoneal

4

What happens to smooth muscle at the rectosigmoid junction

Teniae coli of the sigmoid colon spread to form a continuous outer longitudinal layer of smooth muscle

5

What are the major flexures of the rectum

Sacral
Anorectal

6

What is the sacral flexure

Anteroposterior curve following the curve of the sacrum and coccyx, therefore it is concave anteriorly

7

What is the anorectal flexure

Anteroposterior curve that is concave posteriorly

8

What forms the anorectal flexure

Tone of the puborectalis muscle

9

Function of the anorectal flexure

Contributes significantly to faecal continence (ability to control bowel movements)

10

What are the lateral flexures of the rectum

Superior
Intermediate
Inferior

11

What forms the lateral flexures

Transverse folds of the internal rectal wall

12

What is the distal segment of the rectum

Ampulla

13

Function of the ampulla of the rectum

It relaxes to accumulate and temporarily store faeces until defecation occurs

14

What's directly anterior to the rectum in males and females

Males - rectovesical pouch
Females - rectouterine pouch

15

Link embryological origins to the blood supply of the rectum

The proximal rectum is derived from the hindgut and so its blood supply is via the inferior mesenteric artery
The distal rectum receives its blood supply from branches off the internal iliac arteries

16

Arterial supply of the proximal rectum

Aorta -> IMA -> right and left superior rectal arteries

17

Arterial supply of the distal rectum

Aorta -> common iliac -> right and left internal iliac -> right and left middle rectal arteries
Aorta -> common iliac -> right and left internal iliac -> inferior pudendal -> right and left inferior rectal arteries

18

Venous drainage of the rectum

Superior, middle and inferior rectal veins

19

What does the superior rectal vein drain into

IMV, splenic vein then the hepatic portal vein

20

What do the middle and inferior rectal veins drain into

Systemic venous system

21

Site of the portocaval anastomosis (where do the portal and systemic venous systems anastomose)
What is the significance of this

Wall of the anal canal
Clinically important in varices (portal hypertension)

22

Innervation of the rectum

Sympathetic - lumbar splanchnic nerves and the superior and inferior hypogastric plexuses
Parasympathetic (S2-4) - pelvic splanchnic nerves and inferior hypogastric plexus

23

What does lymph from the rectum drain into

Pararectal lymph nodes
Additionally, lymph from the distal rectum drains directly into the internal iliac lymph nodes

24

What do pararectal lymph nodes empty into

Inferior mesenteric nodes

25

What can be palpated digitally via the rectum

Prostate
Seminal vesicles
Cervix
Sacrum
Coccyx