Hello anatomy colleagues this is Dr Alsup and in this learning objective video we will be
discussing the hip joint. So I'm guessing you have a pretty good idea where the hip joint is actually
located so we will spend the majority of our time discussing some of the major accessory structures
including ligaments and tendons. As always we will discuss the movements possible at the
hip joint and any other pertinent clinical information in this area.
The hip joint is the other major ball and socket joint and because of this it's one of the
most mobile joints in the body. In fact it is the second most mobile joint in the body second to the
glenohumeral or the shoulder joint. Now it is kind of the exception to the rule that mobility means
decreased stability as the hip joint is a very stable joint, which makes sense if you think
about the amount of weight that is moving through the body through the hip joint and of course what
needs to occur with locomotion. You need a lot of stability here with a fair share of mobility.
The stability is very dependent on a variety of things such as accessory structures which
we will talk about in a moment, but it also has to do with the fit of the articulating bones and
so you have this relatively deep socket which is the acetabulum of the coxal bone and that
is going to allow the fit of this large head of the femur so those are the two articulating bones.
There are so many accessory structures associated with the hip joint we could
spend half of your curriculum here but alas we cannot so I'm going to focus on
three representatives in this area that play a major role in stability and protection.
The first is the acetabular labrum and I hope you recall back in our first
discussions of synovial joints that labra are associated with ball and socket joints
and so of course we will find a fibrocartilaginous lip associated with this area, so with the
acetabulum here, so you have you can see a bit of it right here you can see a bit of it right here.
And this provides an additional component of strong fit between the acetabulum and the head
of the femur. Additionally there are numerous ligaments associated with the hip joint as you
can see in the images here but the largest and most dominant one is the iliofemoral
ligament, you can see it labeled here it's making up the bulk of this region here. This is the
largest and most dominant it is sometimes referred to as the Y ligament based on its so-called shape.
In some literature or textbooks you hear this referred to as the strongest ligament of the body.
I am not quite positive that that is true but is certainly
among the top five list and it is most certainly the most prominent ligament in this hip joint.
It is more anteriorly placed extending between the ilium, so here's the ilium, and the femur.
And even though it's more anteriorly placed even if you're looking at a posterior view
which you can see here you can see a bit of the iliofemoral ligament as well.
Other than of course providing overall stability and protection at the joint the iliofemoral
ligament also specifically prevents hyperextension so extension past where it should of the hip joint
so both during active movement as well as during standing it really serves to prevent
hyperextension, so that's important in terms of stamp space as well as in terms of locomotion.
Ligaments aren't the only protectors in this area, tendons and muscle bellies play
a huge role as well specifically the medial and lateral rotators
of the hip joint, so those are really closely associated and closely located
with the hip joint, and we will be discussing those in upcoming learning objectives.
The hip joint is capable of all actions that a ball and socket joint can do which is all
the actions really that a synovial joint can do, so you can have flexion and extension so think
flexion is moving the thigh anteriorly in the sagittal plane with extension moving it back,
abduction you're going to have moving away from the body as you can see here in that
coronal plane and adduction is moving back and you put those four movements together
and you can have circumduction of the hip joint. Recall also that ball and socket joints are also
capable of rotation with medial or internal rotation and lateral or external rotation.
Before we finish our conversation on the hip joint I do want to focus in on one clinical
consideration which are fractured hips. Fractured hips are rarely fractures to the coxal bones but
instead typically a fracture of the proximal femur and one of the most common areas for fracture
is the neck so this right here is the neck of the femur, and as you can see there are numerous
types of neck fractures that can occur, and by the way I don't want you to memorize this image
in terms of the specifics here I just kind of have it here more in terms of
telling you or showing you the types of fractures that can occur.
Femoral neck fractures are most common in older individuals particularly those that also have
osteoporosis and what's important here other than the fact that of course it's a fracture
in this region can certainly affect hip motions. It's also that these fractures
often disrupt blood supply so those small their smaller retinacular arteries from the medial
circumflex femoral artery. If these are disrupted you're left with a pretty weak blood supply,
there's a little branch traveling in this ligament right here the ligament of the head of the femur
but it's typically not sufficient or is inadequate for maintaining the femoral head
blood supply, so this area may undergo avascular necrosis without intervention.
Excellent we have reached the summary slide. Please take time to review and as always please reach out
if you have any questions. Thank you for your time and attention and have a great rest of your day