hello anatomy friends this is dr alsup and in this video we will be discussing the anatomical
considerations regarding inguinal hernias with our major goal of being able to anatomically
differentiate between an indirect and a direct hernia so the two major types of inguinal hernias
so what even is an inguinal hernia so inguinal hernias are protrusions or herniations
of both parietal peritoneum and often viscera such as portions of the small intestine through
a normal or an abnormal opening in the inguinal region an inguinal hernia is the most common
type of hernia in the abdominal region so other types of abdominal hernias include
umbilical hernias which as the name would suggest involve the umbilical region
you can also have incisional hernias so a hernia caused by a surgical incision
and even femoral hernias are often considered in the abdominal region as they are near but
certainly inferior to the inguinal region so these are often lumped or considered as
portions or types of abdominal hernias but inguinal hernias are going to be the most common
there are two types of inguinal hernias there are indirect
and direct and these are often difficult to differentiate
in terms of a clinical exam both types of inguinal hernias can happen to any individual
but are more common in individuals with spermatic cords and testes due to the relatively larger size
of the the inguinal canals with the descent of the testes into the scrotum so ovaries do not
traverse the inguinal canal whereas the testes do so there's a relatively larger size there
okay so let's talk about the differences between these types of inguinal hernias
first we will start with just overall frequency and indirect hernias are more
common about two-thirds of inguinal hernias are indirect inguinal hernias so easy enough
we got that one down all right now we get into some of the fun stuff
both indirect and direct hernias will protrude and sometimes travel through the inguinal canal all
right so both are going to have some role in terms of that inguinal canal that we've talked about
now how they get there differs remember this friend the lateral umbilical fold that we've
talked about in other videos it's that fold that's formed by peritoneum covering the inferior
epigastric vessels while a direct inguinal hernia will enter the canal medial
to the inferior epigastric vessels so a direct would be medial whereas an indirect will enter
lateral to both both the inferior epigastric vessels and of course the lateral umbilical fold
is created by peritoneum lying over those structures so direct will always be medial
and indirect will always be lateral so to be more specific recall that the deep inguinal ring
or that entryway to the inguinal canal is just lateral to the inferior epigastric vasculature
so an indirect inguinal herniation will enter the inguinal canal through the deep inguinal ring
okay that is an important difference here so it will often it will go through that deep inguinal
ring and often will traverse the entire inguinal canal and sometimes beyond the inguinal canal
a direct inguinal herniation i always think of as not having time to go through an already
existing entryway it is more direct it just kind of pushes its way through into the inguinal canal
through an area of weak fascia in the inguinal triangle
all right so over here lateral we'll have that indirect the direct is going kind of straight
through some of that weak fascia in the inguinal triangle recall that that inguinal triangle
is bounded by the inferior epigastric vasculature superior laterally the inguinal ligament down here
inferiorly and the rectus abdominis muscle more medially so that is that inguinal triangle
sometimes you hear it referred to as the triangle of Hesselbach
now as mentioned inguinal hernias can happen in any individual but are more common in individuals
with spermatic cords and testes due to that relatively larger size based on the descent
of the testes to the scrotum and with this there is the possibility that the herniation can extend
past the inguinal canal all the way to the scrotum this is pretty rare in terms of direct
inguinal hernias but are possible with indirect inguinal hernias particularly in
individuals with what is referred to as a patent processus vaginalis so this processus vaginalis
is a naturally occurring structure in utero it's an extension of peritoneum that traverses the
inguinal canal to the scrotum during development and it will precede the descent of the testes
now what happens right around birth is that proximal portion of the processes vaginalis
will occlude or close um with a persistent portion surrounding the testes but the point is that that
pathway between the peritoneal cavity and the scrotum is closed typically those with a patent
or open or persistent processus vaginalis would allow an easier pathway for herniation contents
to descend from the peritoneal cavity as far as that tunica vaginalis of the testes in the scrotum
sometimes you hear that pathway of an indirect hernia
is comparable to the pathway followed during the descent of the testes
now sometimes you hear the indirect inguinal hernias being referred to as congenital and that
processus vaginalis or the persistent one that's what it's referring to the fact that the processus
vaginalis did not become occluded at birth um thus predisposing to that type of herniation to occur
indirect inguinal hernias can be congenital as we just mentioned but they can also be acquired
as well and caused by weakened fascia around the deep inguinal ring and examples of say like
straining with heavy and unstable lifting that can cause herniation through the deep inguinal ring
sometimes can cause the expansion or change in shape of the deep inguinal ring direct
inguinal hernias are always caused by an acquired weakness of the posterior wall of the inguinal
canal specifically that within that inguinal triangle region that we discussed previously
excellent so i have put this information in a handy dandy chart easy to read chart
that you can find here in your summary slide please review this information
and reach out to me or any of my anatomy colleagues regarding remaining questions
thank you for your time and attention and i hope you have a great rest of your day