So, inguinal hernias, we have got on our abdomen
a series of slits of openings that allow the
testes... that allowed the testes to migrate
from the posterior abdominal wall through
into the scrotum. So, these are potential
sites of weakness. On the screen at the moment,
we can see a gentleman who has a right inguinal
hernia. This is going to be the protrusion.
A hernia is a protrusion of a structure through
the wall that surrounds it, okay?
So, the protrusion of a structure, in this case a
piece of intestines, through the wall that
surrounds it. In this case, intestines passing
through the anterior abdominal wall.
They don’t puncture the skin, obviously, but
they are penetrating those muscular membranous
layers and we can see this inguinal hernia
here, we can see this bulge, it’s present
on the right hand side, it’s not present
on the gentleman’s left hand side.
So, he has a right inguinal hernia. What’s happened
here? How does it occur? Well, as I said,
and we can see here in some details, it’s
the protrusion of an organ through the wall
of the compartment that contains it. So, if
we think about how this could occur, changes
in intra abdominal pressure. I mentioned that’s
an important function of the muscles of the
anterior abdominal wall. So, as chronic coughing
or sneezing where you are contracting those muscles,
changes in intra abdominal pressure,
lifting, if you are bending over then that’s
going to be putting pressure on the abdominal
wall muscles. The content of the abdomen,
the intestines, as we will see later on the
abdomen is full of the intestines.
So, these intestines can be forced out through a weakness.
Potential sites of weakness?
The inguinal rings that form the inguinal canals. We have
two, if you remember, inguinal rings. We have
two, therefore, sites of weakness, a superficial
and a deep and depending on the degree of
increases of intra abdominal pressure or depending
on the degree of closure of the deep inguinal
ring as the testes pass through during development
can lead to one of these inguinal hernias.
We again have two different types depending
on the intestine passing through even the
superficial, which we’d call it direct,
or passing through the deep, which we’d
call an indirect inguinal hernia.
So, let’s have a look at the mechanism of
how this could occur. So again, we are going
back to the previous diagram. Here, we have
got our inferior epigastric artery and we
are going medial this time to our inferior
epigastric artery. On this side, we have got
our inferior epigastric artery and we are
going lateral. This is the midline, so, we
are going lateral to it. What do we find lateral
to the inferior epigastric artery?
We find the deep inguinal ring. So, here we have the
deep inguinal ring. Medial to inferior epigastric
artery, we find the conjoint tendon. The
conjoint tendon that was formed by internal
oblique and transversus abdominis muscle fibers
to strengthen the posterior wall of the inguinal
canal in line with the superficial inguinal
ring, but with continued increases in pressure,
this can be pushed upon and
exacerbate that weakness.
So, if we just, first of all, look at the
direct inguinal hernia, the direct inguinal
hernia which is associated with the superficial
inguinal ring. The protrusion occurs at the
level of the superficial inguinal ring where
the testes are pushing against the conjoint
tendon. It occurs medial, this is the midline
remember, it occurs medially to those inferior
epigastric arteries. But importantly, it
passes through the superficial inguinal ring,
but it takes with it, a hernial sac. That means
it’s very much like pushing your finger
through a balloon and as your finger goes
through that balloon, it still takes a covering
of the balloon with it. So, here we can see
the peritoneum and we can see the transversalis
fascia and here, we can see that we have created
this hernial sac and this hernial sac can
actually be popped back in. So, if you cough,
a piece of intestine can go through and then
if you just palpate your groin, your inguinal
region then you can push this hernial sac
back in and you can do this routinely until
you can go and seek some medical assistance.
So, here we have a direct inguinal hernia,
this doesn’t really enter the scrotum.
This is in contrast to an indirect inguinal hernia,
so it is called a congenital one because it’s
to do with a patent processus vaginalis. So,
what’s that? That is a failure of the deep
inguinal ring to sufficiently close once the
testes has migrated through. So, here we can
see the vas deference would be passing through
the deep inguinal ring. If the deep inguinal
ring doesn’t close up, you have got this
opening and this allows a piece of intestine
to pass through this deep opening, but now,
it’s not in any way limited by hernial sac
because it’s just utilising the passageway
that is the inguinal canal, where previously
a direct one was limited by this hernial sac.
Now, this indirect one, through the deep inguinal ring,
lateral to epigastric arteries and veins
is now running within the inguinal canal itself
and therefore, this piece of intestine can
actually enter into the scrotum and you could
have a very swollen scrotum, we
have the contents, we have the intestines
being within it and this is particularly serious
because you wouldn’t want a piece of intestine
to become constricted with contractions of
those muscles and then it to become ischemic
and die off within the scrotum.
So, this needs to be dealt with very quickly.
So, we can see we have two different types
of hernia. A direct one associated with superficial
inguinal ring and an indirect one associated
with the deep inguinal ring.
And that’s it. We have looked at the inguinal
region and specifically, the inguinal canal.
We started off by looking at some important
surface landmarks, the anterior superior iliac
spine, the inguinal ligament running towards
the pubic tubercle or the pubic crest.
And then we looked at the boundaries of the inguinal
canal, the openings, the superficial, deep
inguinal rings and the contents, the spermatic
cord in the male and the round ligament of
the uterus in the female. And then to finish
up, we looked at indirect and direct hernias,
being an indirect, being a congenital and
positioned lateral to epigastric vessels entering
the scrotum and the direct which is more acquired,
happens with activities, medial to inferior
epigastric vessels and this one rarely enters