Lecture 21 - perineum: anal triangle Flashcards
(36 cards)
What ia the perineum/
region below the pelvic floor - between the thighs
it has the same diamond shaped boundaries as the …
pelvic outlet:
differently organised
horizontal between the ishail tuberosities -
what are the two triangles created?
urogenital and anal
what are the boundaries of the perineum?
symphysis pubic on top
ishail tuberosities on each side
coccyx at the bottom
The urogenital triangle is further subdivided into a..
What divides them?
superificial and deep (close to pelvic floor)
divided by the peroneal membrane
peroneal membrane has a free _____ edge
posterior
the superifical part of the peroneal membrane is the anchor point for…
the external genitalia
the deep surface of the peroneal membrane is a muscular diaphragm made up of the ______
sphincters of the tubular structures
The free posterior edge of the peroneal membrane is reinforced by muscles called
superifical transverse perineal msucle
deep transverse erineal muscles
(mirrored)
What is the name of the fat filled space between the ishium and anal canal?
ishiorectal fossa
The side wall of the perineum is the inferior half of …
obturator internus (below the linear attachment of levator ani)
Where does the NV bundle of the perineum run?
the pudendal canal - in the fascia overlying obturator internus
There is angulation of rectum/anal canal is….
hat maintains it?
downwards and backwards
created by puborectalis
The upper 2/3 of the anal canal is lined by ..
and supplied by…
mucosa -
Sup. rectal artery
veins draining to the portal system
The upper 2/3 of the anal canal is innervated by -
autonomic nerves
what delineates the upper 2/3 from lower part of anal canal
pectinate line -
the lower 1/3 of the anal canal is arterial supplied by
inferior rectal artery - branch of iliac system
drains to systemic veins
true or false
there is a porto-systemic anastomosis at the anal canal
true
the venous plexus can become engorged
the lower 1/3 of the anal canal is innervated by
somatic nerves
inf. rectal branch of pudendal nerve
describe the internal anal sphinter
thickening in smooth muscle wall - autonomic control
describe the external anal sphinter
3 components
deep
superficial
subcutaneous
The deep component of the external anal sphincter fuses with..
puborectalis - at the ano-rectal junction
The superficial component of the external anal sphincter is fixed anteriorly and psoteriorly to what?
posteriorly: tip of the coccyx
anteriorly: a fibrous thickening of the free posterior border of the perineal membrane called the perineal body - also called a central tendon
what mscles are connected to the central tendon or perineal body?
sup and deep transverse perineal muscle
superfiical component of the ext. anal sphincter
levator ani
all of the perineal sphincter assoc. with the vagina