Anatomy- Faecal Continence

Question 1

what is the role of the rectum

Answer 1

a holding area to store faeces until appropriate to defecate

Question 2

what senses the fullness (stretching) of the rectum

Answer 2

normal visceral afferent nerve fibres

Question 3

what can affect faecal continence

Answer 3

neurological pathology, medications, old age degeneration of nerve innervation of muscle, consistency of stool

Question 4

what does the pelvic cavity lie within

Answer 4

the bony pelvis- between the pelvic inlet and pelvic floor

Question 5

what is the pelvic cavity continuous with

Answer 5

abdominal cavity

Question 6

what separates the abdominal cavity and the pelvic cavity

Answer 6

peritonium

Question 7

what does the pelvic cavity contain

Answer 7

pelvic organs and supporting tissues- inc rectum

Question 8

what muscle is known as the pelvic floor

Answer 8

levator ani

Question 9

what do openings in the levator ani allow

Answer 9

distal parts of the alimentary, renal and reproductive tracts to pass from the pelvic cavity to the perineum

Question 10

at what vertebrae does the sigmoid colon become the rectum

Answer 10

anterior to S3 (recto-sigmoid junction)

Question 11

where does the rectum become the anal canal

Answer 11

anterior to the coccyx just prior to passing through the levator ani muscle

Question 12

are the rectim, anal canal and anus in the pelvis or perineum

Answer 12

rectum in pelvis

anal canal and anus in the perineum

Question 13

what is the difference between sigmoid and rectum

Answer 13

looses tinae coli and has longitundinal muscle fibres

Question 14

where is the rectal ampulla

Answer 14

lies immediately superior to the levator ani muscle

Question 15

why does the rectum have three folds

Answer 15

create staggering effect, allow for expansion

Question 16

what part of rectum in under conscious control

Answer 16

the sphincters

Question 17

what covers the superior rectum

Answer 17

peritoneum

Question 18

what lies anterior to the superior rectum

Answer 18

rectouterine (pouch of douglas) /retrovesical pouch

Question 19

what lies anterior to the inferior rectum in males

Answer 19

prostate

Question 20

what lies anterior to the middle/inferior rectum in females

Answer 20

the vagina

Question 21

what type of muscles make up the levator ani

Answer 21

skeletal- controlled consciously

Question 22

where does the puborectalis go between

Answer 22

both pubic bones- most medial

Question 23

where does the pubococcygeus go between

Answer 23

from pubic bone to coccyx

Question 24

where does the illiococcygeus go between

Answer 24

inner side of ischium to coccyx

Question 25

what muscles makes up the levator ani

Answer 25

puborectalis illiococcygeus pubococcygeus

Question 26

when does the levator ani reflexively contract

Answer 26

during increased intra-abdominal pressure (coughing sneezing)

Question 27

what innervates the levator ani

Answer 27

'nerve to levator ani' (branch of sacral plexus) and pudenal (main nerve of perineum) S2,3,4 (keeps the poo off the floor)

Question 28

what does the pubrorectalis do to maintain faecal continence

Answer 28

acts like a sphincter by contracting and decreasing the anorectal angle (skeletal so under voluntary control)

Question 29

what are the two anal sphincters

Answer 29

interal (smooth muscle) and external (skeletal)

Question 30

what stimulates the internal anal sphincter to contract

Answer 30

sympathetic stimulation

Question 31

where is the internal anal sphincter

Answer 31

superior two thrids

Question 32

contraction of the internal anal is inhibited by what

Answer 32

parasympathetic nerves

Question 33

when is the internal anal sphincter normally contracted and relaxed

Answer 33

contracted all the time- relaxes reflexively in response to distension (filling) of the rectal ampulla

Question 34

where is the external anal sphincter

Answer 34

inferior two thirds of the anal canal (superior part continuous with the puborectalis muscle)

Question 35

what stomulates the external anal sphincter to contract

Answer 35

pudendal nerve

Question 36

when does the external anal sphincter voluntarily contract

Answer 36

in response to rectal ampulla distention and internal sphincter relaxation

Question 37

what separates the pelvis from the perineum

Answer 37

the levator ani- above pelvis, below perineum

Question 38

what type of nerves supply structures in the pelvis

Answer 38

body cavity- sympathetic, parasympathetic, visceral afferent

Question 39

what type of nerves supply structures in the perineum

Answer 39

body wall- somatic motor and sensory

Question 40

what are the important spinal chord levels for nerve supply to the rectum/ anal canal

Answer 40

T12-L2 and S2-4

Question 41

what is the path and role of the sympathetic fibres from T12- L2

Answer 41

travel to inferior mesenteric ganaglia- synapse- then travel via parietal plexus around branches of the IMA - contraction of internal anal sphincters - inhibit peristalsis

Question 42

what is the path and role of the visceral afferent coming back to S2-4

Answer 42

run with the parasympathetics | -sense stretch, ischaemia etc

Question 43

what is the path and role of the parasympathetic fibres from S2-4

Answer 43

via pelvic splanchnic nerves, synapse in walls of rectum - inhibit internal anal sphincter - stimulate peristalsis

Question 44

what is the role of the somatic motor from pudendal nerve S2-4 and nerve to levator ani

Answer 44

contraction of external anal sphincter and puborectalis

Question 45

what is the pudendal nerve a branch of

Answer 45

the sacral plexus

Question 46

what anterior ramis makes up the pudendal nerve

Answer 46

S2,3,4

Question 47

via what does the pudendal nerve exit the pelvis

Answer 47

greater sciatic foramen

Question 48

how does the pudendal nerve enter the perineum

Answer 48

via lesser sciatic foramen

Question 49

what damage could result to loss of pelvic control during labour

Answer 49

tear of perineum, stretch of pudendal nerve, tear of puborectalis or external anal sphincter muscle fibres

Question 50

what is the pectinate line

Answer 50

marks the junction between the part of the embryo that formed the GI tract (endoderm) and the part that formed the skin (ectoderm)

Question 51

what changes when you cross the pectinate line

Answer 51

arterial supply, venous drainage, nerve supply, lymphatic drainage (superior= visceral inferior = parietal)

Question 52

describe the nerve supply above and below the pectinate line

Answer 52

above- autonomic | below- somatic and pudendal

Question 53

describe the arterial supply above and below the pectinate line

Answer 53

above- from IMA | below- from internal iliac artery

Question 54

describe the venous drainage above and below the pectinate line

Answer 54

above- to hepatic portal sysetm (via IMV) | below- to systemic venous system (internal iliac)

Question 55

describe the lymphatic drainage above and below the pectinate line

Answer 55

above- inferior mesenteric nodes (internal iliac nodes) | below- superficial inguinal nodes

Question 56

why may cancer above the pectinate line not be felt

Answer 56

as visceral sensory only

Question 57

where do lymph vessels tend to lie

Answer 57

alongside the arteries

Question 58

what are the main groups of lymph nodes draining the pelvic organs and what does each drain

Answer 58

internal iliacs- inferior pelvic structures external iliacs- lower limb, more superior pelvic structures common iliac- drains external and interbal iliac nodes lumbar nodes- lymph from common iliac nodes then goes to here

Question 59

what artery supply with hindgut organs

Answer 59

IMA

Question 60

what is the hindgut

Answer 60

distal 1/3rd of the transverse colon to proximal ½ of the anal canal (the ½ superior to the pectinate line)

Question 61

what supplies the GI past the pectinate line (past the hindgut)

Answer 61

internal iliac artery (branches into middle and inferior rectal artery)

Question 62

what vein drains the hindgut organs

Answer 62

superior rectal vein- | IMV- portal venous system

Question 63

what vein drains below the pectinate line

Answer 63

middle and inferior rectal vein- internal iliac vein- | systemic venous system

Question 64

when do rectal varices from

Answer 64

when there is portal hypertension- dilatation of collateral veins between portal and systemic systems

Question 65

what are haemorrhoids and what causes them

Answer 65

prolapses of the rectal venous plexuses- NOT RELATED TO PORTAL HYPERTENSION- but caused by raised pressure (chronic hypertension, straining, pregnancy)

Question 66

where are the ischioanal fossae

Answer 66

lie on either side of the anal canal

Question 67

what are the ischioanal fossae filled with

Answer 67

fat and loose connective tissue

Question 68

where do the ischioanal foscae communicate

Answer 68

posteriorly

Question 69

what in an ischioanal abscess

Answer 69

an infection within the ischioanal fossa

Question 70

what do you assess in an digital rectal exam

Answer 70

anal tone- strength/ effectiveness of the anal sphincter palpate the prostate/ cervix

Question 71

what is a proctoscopy

Answer 71

viewing the interior of the rectum

Question 72

what is a sigmoidoscopy

Answer 72

viewing the interior of the sigmoid colon

Question 73

what is a colonoscopy

Answer 73

viewing the interior of the colon