hello anatomy colleagues this is dr alsup and we have finally made it to the muscles of the lower
limb and we're going to start with the gluteal region muscles which are um kind of covering two
bases but they are going to affect the hip joint so talking about them with the lower limb makes
the most sense so we'll talk about the three main muscles in this region and we'll talk a little bit
about a specific clinical correlation at the end so starting with the big one the gluteus maximus
this is our most superficial gluteal muscle i'm outlining it right now it is also our largest
it's our most coarsely fibered it's the heaviest muscle of the body so this
muscle is no joke it is going to be very obvious in terms of its superficial position
as well as just the general size of this muscle and it will actually cover all the other gluteal
muscles so you won't be able to see the medius or minimus at all except you do see a little bit
of the gluteus medius extending superiorly just above the gluteus maximus but it's very covered
with what's referred to as gluteal fascia but you can see a little peek of the gluteus
medius and you can't see any gluteus minimus unless the gluteus maximus has been reflected
the majority of the fibers of the gluteus maximus will insert or have its distal attachment
on the iliotibial band which will be located on the lateral portion of the lower limb and we'll
talk a bit more about the iliotibial band when we get into some muscles of the thigh region
this is going to play a big role here and since it's inserting here it'll play a role in terms
of extension of the hip which we'll get to in a bit more detail in a moment now some of the other
muscle fibers will have a more inferior attachment at the gluteal tuberosity of the femur
but since the majority is going to have an insertion here that's what i want you to focus
on and you can see this particular image says iliotibial band you'll also see a iliotibial tract
okay this muscle has its own innervation so it has a separate innervation from the gluteus medius and
minimus so it will be the inferior gluteal nerve and it will also be supplied by the inferior
gluteal artery as well as the superior gluteal artery and that kind of neurovascular supply
will enter into the deep portion of the muscle at about the mid portion of the muscle the gluteus
maximus will be the main extensor of the hip joint or the most powerful or strongest extensor
of the hip joint but it really only is going to be active in cases where you need more forceful
extension so think right when you're rising from a standing position or from if you're jumping in
that way it's not really going to be playing as much of a role when you're just kind of standing
and while your hip is extended it's not the gluteus maximus that's playing the bigger
role in terms of that movement or that stance so it's really for more of that forceful extension
of the hip joint we'll also play an important role in terms of lateral rotation of the hip
the gluteus medius and minimus as i mentioned will be deep to the gluteus maximus except for this
kind of top portion of the gluteus medius and these muscles are as their names would suggest
indicative of their size so the medius will be kind of intermediate in size in comparison to
the gluteus maximus and minimus and the minimus will be the smallest one
but they are both going to have kind of a similar shape even though the minimus won't extend as
superiorly and they both will be inserting or having their distal attachment on the greater
trochanter of the femur and that's one of the major reasons why the greater trochanter is so
large in comparison to say the lesser trochanter or any other tubercles because these are also
very powerful forceful muscles and they play a very important role in terms of stabilizing the
hip and it does so through abduction and medial rotation of the hip but it's really this abduction
that allows for the gluteus medius and minimus when they can when they contract to allow for the
hip to not dip to one side so it's really playing a role in terms of stabilization
and where the gluteus maximus is going to be innervated by the inferior gluteal
the minimus and medius will be innervated by the superior gluteal nerve so if you have
injury to that superior gluteal nerve you can have what is a presentation of that could be
what's referred to as the gluteal gait or gluteus medius limp and this is what happens to kind of
compensate for weakened abduction so say you have some type of damage to the superior gluteal
nerve on this right side this would not allow for this right gluteus medius and minimus to contract
to allow for this stabilization that typically happens when you lift your foot off the ground so
in this particular case in the typical case the superior gluteal nerve is not injured
it allows for the right medius and minimus to contract when you lift up your left foot
and that when it contracts it will abduct and allow for stabilization of the hip
whereas if you do not have that contraction occurring with these muscles it would allow
for the hip to dip on the uninjured side because this side is not stabilizing
so oftentimes this is um this sign of this dip would be referred to as a positive trend
dillingberg sign or test and it causes that lower limb to almost appear too long it has a hard time
kind of clearing the ground because the the pelvis has dipped to that one side because you
don't have the compensation of the medius and minimus on the other side contracting
okay excellent so innervation seemed key here and we spent a lot of time on superior gluteal nerve
but what is that inferior gluteal nerve innervate which muscle here is it the maximus
medius or minimus and i'm just going to give you a second because hopefully this is a nice quick
uh recall but recall the medius and minimus are going to be superior gluteal nerve so that was
where that trendelenburg sign and gluteal gait if you have injury to the superior gluteal nerve the
gluteus maximus has its own innervation which is the inferior gluteal nerve and so that makes this
the correct option okay excellent thank you so much for your time and attention here we
will now move on to the muscles of the thigh region and there's quite a few compartments
there that we have to work through have a fun time reviewing this material please
reach out if you have any specific questions and i hope you have a great rest of your day