So let's just stay with the ischioanal fossa
and look at its lateral wall for one moment.
So the ischioanal fossa and the lateral wall.
Now, what I have got here as well
is the branching of
the internal iliac artery
that we did in a previous lecture.
Because now we need to remember
the arrangement of the
internal pudendal artery.
So what we have done is... We have got a
image of a ischioanal fossa here.
We have got the levator ani
and we have got our obturator internus
membrane. Well same on this side.
And if we turn to this diagram,
we can imagine that the
pelvis has been sectioned
coronally down like this
in this direction. So if we section coronally down
and that's what we are looking at on this side.
So what have we done? Well, we have cut through
the ischium which we can see here.
We have cut through the ischium which
we can see here and we have also
cut through an important blood vessel.
We have cut through this blood vessel here.
Now if I just get rid of those previous marks
we can see that we have cut
through this blood vessel.
Now what did this blood vessel
do? It left the pelvis
via the greater sciatic
foramen inferior to piriformis.
It left via the left
greater sciatic foramen.
It then hooked around ischial spine
sacrospinous ligament. It
hooked around. And now
as it hooked around the sacrospinous ligament
remembering the coccygeus
runs on the pelvic surface
of the sacrospinous ligament.
Its now going to be running
under the pelvic floor.
So it left the pelvis, hooked around
ischial spinous, sacrospinous ligament
to now run within the perineum.
It found a way to run
underneath the pelvic floor.
Now it's running alongside
the ischiopubic ramus.
As we cut through it we can just make out
the internal pudendal artery there.
Running alongside in this direction.
Obturator internus muscle in a structure
known as the pudendal canal.
This is an important compartment
within obturator internus fascia.
And it contains the pudendal nerve which is
important in providing innervation to the perineum.
But importantly, looking at the arterial
supply from the internal iliac,
it's containing the
internal pudendal artery
and also the internal pudendal nerve.
It's running along the medial aspect
of the ischiopubic ramus, running
along the lateral wall
of the ischioanal fossa. Coming from it
are going to be the nerves
and blood vessels that supply
the inferior part of the anal canal.
Supply this region down here.
So running through the ischioanal fossa
we going to be having the inferior
rectal nerve, artery and vein
running through the ischioanal fossa to
supply the inferior anal canal.
Okay, in future slides we'll carry on looking at the
branching pattern of this internal pudendal artery.
But really that's all I want to say about the
ischioanal fossa. It's a really important space.
The fact that we have this fat
filled space lateral to the rectum
allows for the faeces to expand
into this space during defecation.