GB 21. Rectum, Anal Canal, Ischiorectal Fossa Flashcards

1
Q

What is the blood suppy of the rectum? [main arteries]

A

[1] Superior Rectal Arteries
[2] Middle Rectal Arteries
[3] Inferior Rectal Arteries

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2
Q

Which artery (ies) supply the first half of the anal canal?

A

Superior Rectal Artery

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3
Q

Which artery (ies) supply the lower half of the anal canal?

A

Middle Rectal Artery + Inferior Rectal Artery

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4
Q

What is the venous drainage of the rectum? [main veins]

A

[1] Superior Rectal Vein
[2] Middle Rectal Vein
[3] Inferior Rectal Vein

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5
Q

Which vein(s) drains the first half of the anal canal?

A

Superior Rectal Vein

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6
Q

Which vein(s) drains the second/lower half of the anal canal?

A

Middle Rectal Vein + Inferior Rectal Vein

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7
Q

What are the 3 muscles that make up the Levator Ani muscle?

A

[1] Iliococcygeus Muscle
[2] Pubococcygeus Muscle (Puborectalis Muscle)
[3] Ischiococcygeus Muscle

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8
Q

What nerve innervates the Levator Ani muscles?

A

Pudendal Nerves

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9
Q

What is the Midline Raphe?

A

where the pubococcygeus muscles insert (into the midline)

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10
Q

What is the sensory innervation of the saddle region (what you sit on)?

A

S2, S3, S4

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11
Q

What are the nerve roots that innervate the rectum?

A

S2, S3, S4

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12
Q

What is the Superior Rectal Artery a branch of?

A

continuation of Inferior Mesenteric Artery

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13
Q

What is the Middle Rectal Artery a branch of?

A

branch of Internal Iliac Artery

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14
Q

What is the Inferior Rectal Artery a branch of?

A

branch of Internal Pudendal Artery

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15
Q

Where does the Superior Rectal Vein drain into?

A

Inferior Mesenteric Vein

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16
Q

Where do the Middle and Inferior Rectal Veins drain into?

A

directly into the inferior vena cava

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17
Q

List the POSTERIOR branches of the Internal Iliac Artery in MALES.

A

[1] Iliolumbar Artery
[2] Lateral Sacral Arteries (2)
[3] Superior Gluteal Artery

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18
Q

List the POSTERIOR branches of the Internal Iliac Artery in FEMALES.

A

[1] Iliolumbar Artery
[2] Lateral Sacral Arteries (2)
[3] Superior Gluteal Artery

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19
Q

List the ANTERIOR branches of the Internal Iliac Artery in MALES.

A
[1] Umbilical Artery 
[2] Obturator Artery
[3] Internal Pudendal Artery
- what comes off of this? 
[4] Inferior Vesical Artery*
[5] Middle Rectal Artery
[6] Inferior Gluteal Artery
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20
Q

List the ANTERIOR branches of the Internal Iliac Artery in FEMALES.

A
[1] Umbilical Artery 
[2] Obturator Artery
[3] Internal Pudendal Artery
[4] Vaginal Artery*
[5] Middle Rectal Artery
[6] Inferior Gluteal Artery 
[7] Uterine Artery
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21
Q

What is the common area where the rectum begins in both males and females?

A

3rd sacral segment

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22
Q

Where does the rectum begin and end in males?

A

Begin: 3rd Sacral Segment
End: Apex Prostate

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23
Q

Where does the rectum begin and end in females?

A

Begin: 3rd Sacral Segment
End: Lower 1/4 of Vagina

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24
Q

What are the peritoneal relations of the rectum in all 3 parts?

A

Upper 1/3: Front + Sides

Middle 1/3: Front Only

Lower 1/3: None

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25
Q

What are the rectal valves of Houston? How many rectal valves are there?

A

they are indentations of the rectum (an inward fold - mucosal folds)

Total 3:

  • 2 on the Left
  • 1 on the Right
26
Q

What are the posterior relations of the rectum in males?

A

[1] sacrum + coccyx
[2] lower sacral nerves
[3] rectal vessels + lymphatics

27
Q

What are the anterior relations of the rectum in males?

A

[1] upper 2/3s covered by peritoneum
[2] coils of small intestine
[3] Lower 1/3 (base of bladder, prostate, seminal vesicles)

28
Q

What are the lateral relations of the rectum in males?

A

supported by the Levator Ani

29
Q

What are the lateral relations of the rectum in females?

A

supported by the Levator Ani

30
Q

What are the posterior relations of the rectum in females?

A

[1] sacrum + coccyx
[2] lower sacral nerves
[3] rectal vessels + lymphatics

31
Q

What are the anterior relations of the rectum in females?

A

[1] upper 2/3s covered by peritoneum
[2] coils of small intestine - lying in Pouch of Douglas (rectum-bladder + rectum-uterus)
[3] Lower 1/3 (cervix uteri, vagina)

32
Q

What is the venous anastomoses in the rectum?

A

between the portal inferior mesenteric vein and the system middle rectal vein

33
Q

What angle is the anorectal junction?

A

90 degree angle

34
Q

What cell type(s) is/are a part of the upper anal canal?

A

Coloumnar Cells

35
Q

What cell type(s) is/are a part of the lower anal canal?

A

Squamous Epithelium

36
Q

What junctions in the body is where coloumnar cells turn into squamous epithelium?

A
  • Esophagus

- rectus to anal to skin

37
Q

Describe the main features of the lining of the anal canal?

A

[1] Anal Coloumns
[2] Anal Sinus
[3] Anal Valve

38
Q

What are the 2 distinctive parts of the anal canal?

A

[1] upper 1/2 lined with mucous membrane

[2] lower 1/2 lined with skin

39
Q

What separates the 2 parts of the anal canal?

A

dentate line

40
Q

What is the innervation of the upper half of the canal?

A

autonomic

41
Q

What is the innervation of the lower half of the anal canal?

A

somatic

42
Q

What is the embryological origin of the upper half of the anal canal?

A

hindgut

43
Q

What is the embryological origin of the lower half of the anal canal?

A

anal pit

44
Q

Do both the upper and lower half of the anal canal have the same embryological origin?

A

No, they do not
Upper Half of the Anal Canal - hindgut
Lower Half of the Anal Canal - anal pit

45
Q

What is the lymphatic drainage of the upper half of the anal canal?

A

Inferior Mesenteric Nodes

46
Q

What is the lymphatic drainage of the lower half of the anal canal?

A

Superficial Inguinal Nodes

47
Q

What type of muscle is the internal sphincter made up of? What is its innervation?

A
  • smooth

- autonomic

48
Q

What type of muscle is the external sphincter made up of? What is its innervation?

A
  • skeletal

- somatic (pudendal nerve S2, S3 + S4)

49
Q

What are the 3 parts that the External Sphincter is made up of?

A

[1] Deep
[2] Superficial
[3] Subcutaneous

50
Q

What are the 3 parts that the External Sphincter is made up of?

A

[1] Deep
- puborectalis

[2] Superficial
- attached to perineal body (in front) and coccyx (at back)

[3] Subcutaneous
- beneath skin

51
Q

What are fissures?

A

tears from skin of anal margin to canal

52
Q

What are haemorrhoids?

A

engorgement of venous plexus

53
Q

What is the structure that allows the rectum to have a sigmoid shape?

A

Puborectalis Muscle - that loops around the rectum

54
Q

Where is the perineal body located? Where is it located in regards to the urogenital diaphragm?

A

in the middle line of the perineum at the junction between the urogenital triangle and the anal triangle

  • located at the back of the diaphragm
55
Q

Where is the urogenital triangle?

A
  • between the 2 ischial tuberosities

- to the pubic symphysis

56
Q

Where is the anal triangle?

A
  • between the 2 ischial tuberosities

- to the coccyx

57
Q

What are the layers of the urogenital diaphragm? What is in it?

A

[1] Fascia (on top)
[2] Deep Perineal Pouch (middle)
[3] Perineum (bottom)

  • urethra + (vagina in females)
58
Q

What is the Pouch of Douglas?

A

only in FEMALES
aka rectouterine pouch
- lowest part of body where fluid may collect
- if there is pus in there, you need to take a tool up the vagina to drain it

59
Q

What are the pouches near the rectum that females have?

A

[1] Rectouterine Pouch (important! - Pouch of Douglas)

[2] Vesicouterine Pouch

60
Q

What are the pouch(es) near the rectum that men have?

A

only one!

- Rectovesical Pouch