Faecal continence Flashcards
where is the pelvic cavity?
lies in bony pelvis between the pelvic inlet and pelvic floor
what is contained within the pelvic cavity?
pelvi organs and supporting tissues
is the pelvic cavity continuous with the abdominal cavity?
yes
what separates the pelvic cavity and peroneum?
pelvic floor
what do the openings in the pelvic floor permit?
passing of distal parts of alimentary, renal and urinary tract to pass
through
(only 2 in male as urinary and alimentary combine)
at what vertebral level does the sigmoid colon become the rectum?
S3
“recto-sigmoid junction”
what is the rectal ampulla?
its walls relax to accommodate faecal material
lies immediately superior to the levator ani muscle
what holds faeces in the ampulla until appropriate to defecate?
functioning muscles and muscle sphincters of rectum
what creates the pouches over the pelvic organs?
covering of peritoneum
what is the levator Ani muscle?
skeletal muscle forming most of pelvic diaphragm together with fascical coverings
forms floor of pelvis and roof of perineum
what are the smaller muscles of the levator ani muscle?
iliococcygeus (most lateral)
pubococcygeus (middle)
puborectalis (most medial)
what does the levator ani muscle do?
contracts to hold pelvic organs in
prevents them from moving inferiorly when eg.coughing/sneezing (increasing intra-abdominal pressure)
what is the normal state of the levator ani muscle?
tonically contracted most of the time
what nerve supplies the levator ani muscle?
nerve to lavatory ani (branch of sacral plexus) and pudenal (S2,3,4)
S2,3,4 keeps pelvic organs off the floor
what does the puborectalis muscle do?
voluntary contraction decreases the anorectal angle, acting like a sphincter (maintains continence when rectal ampulla filled with faeces)
which is bigger anal sphincter?
external
made of skeletal muscle (voluntary)
where is the ampulla in the rectum?
widened part
what nerves stimulate contraction of internal anal sphincter?
sympathetic
contraction inhibited by parasympathetic
what part of the anal cancal is covered by the internal anal sphincter?
upper 2/3rds
is the internal sphincter contracted all the time?
yes
what part of the anal canal is covered by the external sphincter?
inferior 2/3rds
overlaps with internal
what nerve stimulates external anal sphincter contraction?
pudenal nerve
what nerves are involved in the pelvic cavity?
sympathetic, parasympathetic and visceral afferent
what nerves are involved in the perineum?
somatic motor and somatic sensory
what artery do the sympathetics “piggy back” on
inferior mesenteric
s 2,3,4 is what give what 2 sets?
somatics to levator ani and parasympthetics to hindgut
what 2 muscles aintain continence?
levator ani
external anal sphincter
what is the craniosaccral outflow?
parasypathetics
what is the pudenal nerve a branch of?
sacral plexus
what is the course of the pudenal nerve?
leaves the pelvic cavity via greater sciatic foramen, loops round a ligament and comes back in via lesser sciatic foramen to supply genitalia/external anal sphincter
what can childbirth damage?
branches of pudenal nerve
fibres in puborectalis or external anal sphincter could be torn leading to muscle weakness and faecal incontinence
what is the pectinate line?
boundary
above = derived from endoderm (inner lining of embryo)
below = derived from endoderm (inner lining of embryo)
what does the pectinate line look like?
zig zag line at anus
why might you not feel any pathology above the pectinate line?
above = visceral supply
what is the course of the lymphatic drainage?
follows arterial supply
what is the difference between rectal varices and haemorrhoids?
haemorrhoids = plexus of dilated veins prolapse down due to prolonged periods of increased pressure (chronic constipation, increased straining, pregnancy) Varices = form in relation to portal hypertension (due to liver cirrhosis etc)
where can haemorrhoids originate from?
internal and external anal sphincter venous plexuses
external hurts more
what are the pros and cons of the fat and connective tissue in the ischioanal fossa?
allows expansion etc
infection/fistula/abscess wouldn’t result in pain so can grow until it travels all the way around and reaches the body wall or forwards into the organs
what is an infection within the ischioanal fossae called?
ischioanal abscess
what are you looking for in a PR exam?
assess anal tone (strength of sphincter)
palpate prostate
palpate cervix
what is a proctoscopy?
viewing interior of the rectum
