the anal triangle

Question 1

what divides the UG and anal triangle?

Answer 1

imaginary line between ischial tuberosities

Question 2

which triangle is found anteriorly?

Answer 2

UG triangle

Question 3

which triangle is found posteriorly?

Answer 3

anal triangle

Question 4

what does the anorectal junction denot?

Answer 4

separation between the rectum and the canal

Question 5

what do the rectal folds lead to?

Answer 5

rectal ampulla

Question 6

what does the bottom portion of the anus transition into?

Answer 6

transitions from being a mucosal membrane to a region where there is perianal skin

Question 7

what is the function of the perianal skin?

Answer 7

Protective mechanism for the anal surface

Question 8

what nerve innervated levator ani muscle?

Answer 8

pudendal N

Question 9

what controls the internal anal sphincter?

Answer 9

automatically controlled by splanchnic nerves

Question 10

what type of control is exerted on external anal sphincter?

Answer 10

somatic

Question 11

what does the perineal body lead to?

Answer 11

leads posterior to anal body

Question 12

what is created by the perineal membrane

Answer 12

deep and superficial perineal pouches

Question 13

what is the ischiorectal fossa?

Answer 13

Pyramidal space located in the anal triangle

Question 14

what is contained within the ischiorectal fossa?

Answer 14

2 large fat pads
Pudendal N
Internal pudendal A & V

Question 15

what borders the ischiorectal fossa?

Answer 15

medial: levator ani
lateral: obturator internus
anterior: recess of ischiorectal fossa
base: skin and fascia

Question 16

are the ischiorectal fossa and deep perineal pouch distinct?

Answer 16

no, they are continuous anteriorly

Question 17

where does the superior rectal A come from

Answer 17

comes from ima

Question 18

where does middle rectal A come from

Answer 18

internal iliac anterior division

Question 19

how does the middle rectal A travel

Answer 19

Enters through the true pelvis and stays deep to levator ani muscle

Question 20

where does the inferior rectal A come from

Answer 20

from internal pudendal A

Question 21

where does the internal pudendal A come from

Answer 21

internal iliac A (anterior)

Question 22

how does the internal pudendal A travel?

Answer 22

Travels by exiting the greater sciatic foramen and travels posterior to the ischial spine to come back through the lesser sciatic foramen and superficial/external to levator ani muscle

Question 23

where can the inferior rectal A be found

Answer 23

Found within the perineum anal triangle

Question 24

where does the superior rectal V drain into? what system?

Answer 24

drains into the inferior mesenteric V

Connects with portal venous system

Question 25

where does the middle rectal V drain into? what system?

Answer 25

Drains into internal iliac V | Connect with systemic/Caval venous system

Question 26

where does the inferior rectal V drain into? what system?

Answer 26

Drains into the internal pudendal V | Connect with systemic/Caval venous system

Question 27

what is a hemorrhoid?

Answer 27

swelling of the internal/external anus where veins tend to stretch causing for improper blood flow and accumulation of blood in stretched veins

Question 28

how is the superior portion of the pectinate line innervated?

Answer 28

autonomic innervation

Question 29

what provides sympathetic innervation to the superior portion of pectinate line?

Answer 29

pelvic and sacrosplanchinic N

Question 30

what types of haemorrhoids are found above the pectinate line?

Answer 30

internal | not painfull due to associated with autonomic NS

Question 31

how is the inferior portion of the pectinate line innervated?

Answer 31

somatic innervation

Question 32

what provides somatic innervation to the superior portion of pectinate line?

Answer 32

Pudendal N (S2-S4) to external anal sphincter and puborectalis

Question 33

what types of haemorrhoids are found above the pectinate line?

Answer 33

external/perianal skin | more painful and visible

Question 34

what is the importance of the pectinate line?

Answer 34

• Divides regions of the rectum and anus supplied by somatic or autonomic innervation, portal or caval drainage, arterial supply from IMA or internal iliac branches and differences between lymphatic drainage

Question 35

what does the SHP split into?

Answer 35

hypogastric N on either side and merges in the inferior hypogastric plexus

Question 36

what provides parasympathetic innervation to rectum and anal canal?

Answer 36

Pelvic splanchnic N via inferior hypogastric plexus

Question 37

what provides sympathetic innervation to rectum and anal canal?

Answer 37

lumbar and sacral splanchnic N

Question 38

what type of innervation Stimulates contraction of the rectum/anus and relaxes the internal anal sphincter

Answer 38

parasympathetic innervation

Question 39

where does sympathetic innervation come from?

Answer 39

IHP

Question 40

what type of innervation Inhibits contraction of the rectum and anus and contracts the internal anal sphincter to prevent defecation (tonic contraction of the sphincter to prevent anal leakage (incontinence)

Answer 40

Sympathetic

Question 41

what is controlled by somatic innervation

Answer 41

Allows control of the urge to defecate and need to release these muscles to allow time to relax for defectation to occur

Question 42

what nerve provides somatic innervation?

Answer 42

Pudendal N to external anal sphincter and puborectalis

Question 43

how does defecation occur

Answer 43

1. Mass movement in the large intestine triggers defecation reflex which stimulates distension in the rectum 2. Contraction of sigmoid colon and rectum 3. Defecation: relaxation of puborectalis and external anal sphincter

Question 44

where does the lumbar splanchic N begin and where does it travel to?

Answer 44

N begin in the SHP & make their way down into IHP

Question 45

where does the sacral splanchic N begin and where does it travel to?

Answer 45

makes their way down directly to the IHP

Question 46

what happens during contraction of the sigmoid colon and rectum

Answer 46

Relaxation of internal anal sphincter (autonomic) | Contraction of external anal sphincter and pelvic floor (puborectalis)

Question 47

what controls the urge to defecate?

Answer 47

pudendal N

Question 48

is reverse peristalsis of fecal matter possible?

Answer 48

yes