In this lecture we are going to look
at the perineum and external genitalia.
So we will look at the perineum
which is this shallow space
inferior or can be considered to be superficial
to the pelvis and the pelvic floor.
We are going to look at the boundaries
and the divisions of the perineum.
And specifically we will look at what's
called the ischioanal fossa.
We will look at its boundaries within
the perineum and also its contents.
And then we are going to look
at the perineal pouches
and these can be particularly complicated.
The deep and the superficial
perineal pouches. And some
sex differences we find
for the male and the female.
And then we will look at the
neurovasculture of the perineum
and return to the internal pudendal artery.
So as I have mentioned at the top, the perineum
is a shallow space which is inferior
or it can be considered
superficial to the pelvis.
It contains a number of important
structures including muscles
and erectile tissues and these
are associated with reproduction.
So, let's first of all let's just try
and orientate ourselves
as to where the perineum is located.
Now here we can see we
have hemisections through
the male and the female pelvis.
We can see we have male here
and other male here and a female.
We have three sections through the pelvis.
We have anterior here and posterior.
Again anterior posterior
anterior posterior. You should be
familiar with these images by now.
And what we can see is here the organs
haven't actually been hemisected
or the bones of the pelvis
have been hemisected.
And on this side that have been
hemisected directly down the midline.
Now what we can do is
just draw a simple line
that separates the
pelvis from the perineum.
So if we go from the pubic symphysis
all the way around up to
the caecum and the coccyx
everything above this line is the pelvis.
Everything below it is the perineum.
We can do the same on these
ones which have been hemisected
through the organs; pubic
symphysis to the coccyx.
We can see everything above it
is the pelvis. Everything below it
is in the perineum. So in the
perineum here we are including the
penis. We are including muscles
that guard the anal sphincter.
In the female we can do the same.
We can see that the urethra passes
through from the pelvis to the perineum
passing through the pelvic floor here.
We can see the same applies for the
vagina here opens up into the vestibule
and we can see the same for the retum
which is here. Here we can identify
some muscles that guard
the anal sphincter.
So this just hopefully
gives an introduction
to where we are going to
be investigating. An area
which is superficial or
inferior to the pelvic floor.
Here is just a sentence which
summarizes what we are going to do
is this investigate the shallow
space superficial/inferior to the pelvic
cavity. And it's levator ani these
muscles that we have been indicating
which we looked out
in the previous lecture
levator ani is going
to be the partition
that forms the pelvic floor
that separates the perineum
from the pelvic cavity.