Let's move on and deep to this
muscle, deep to external oblique,
we find internal oblique.
So here on the diagram,
we can see external oblique here
has been cut away, and we're left with
this muscle that's radiating underneath.
So here we have some details.
You can notice that the
fibers of internal oblique
run in the opposite direction
to that of external oblique,
and this is really important.
So external oblique is running
down in this direction,
like you're putting your hands in
your pockets, external oblique.
We've got some details of its
origin and its insertion here.
It originates from the iliac
crest from the pelvic bone
and also an important piece of fascia most
posteriorly called thoracolumbar fascia.
It also attaches to
the inguinal ligament,
and we'll see that in more detail
when we look at the inguinal canal.
As it's running up
in this direction,
we can see an insert
into ribs 10 and 12.
And also lies some aponeurosis,
which we'll talk about
the internal oblique muscles
attached to the linea alba.
Nerve supply again is similar to
external oblique and rectus abdominis.
And it's the
coming from the spinal
cord T6 through to T12.
Internal oblique does the same
function as external oblique,
it helps to flex and rotate
the trunk enabling us to move
and importantly like I mentioned
before, it helps to compress
the internal viscera, increase the
pressure and support the abdominal cavity.
So we've got internal oblique that
lies deep to external oblique.