0:00

The sagittal projection of the

0:01

hip, often ignored and overlooked.

0:05

In the sagittal projection, especially

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with very thin-section 3D imaging,

0:10

one or two millimeter cuts, we get our

0:13

best view of the hyaline cartilage.

0:15

And while the femur thickness and the acetabular

0:18

thickness vary from front to back, one thicker

0:22

than the other in the front, the other thicker

0:24

than its neighbor in the back, they should

0:27

add up to approximately 3 millimeters and

0:30

should be uniform as in this young patient.

0:34

As we move forward, the overall

0:38

milieu or proteoglycan content of the

0:41

cartilage changes and it gets darker

0:44

as it transitions into the poinsettia.

0:47

Thorn-like labrum, which should not have, in

0:50

young, healthy individuals, any longitudinal

0:53

signal in it, and should not have any horizontal

0:57

signal going more than 25 percent of the

1:00

depth, and certainly not going through it.

1:04

The posterior portion of the acetabular labral

1:07

cup is deeper, craniad to caudad, or superior

1:12

to inferior, than its counterpart in the front.

1:16

There is a ligament in the front, the

1:19

iliofemoral ligament, and there is a

1:21

capsular ligament in the back, mostly

1:23

composed of the ischiofemoral ligament.

1:27

Now let's do a little scrolling.

1:30

We have a T1-weighted and a heavily water-

1:33

weighted fat-suppressed image, both of which

1:36

have a nice complement of fluid within.

1:40

Let's scroll, shall we?

1:43

And as we scroll, we see the anterior

1:46

capsule, and it has innumerable components.

1:49

It has a component that

1:50

is more medial, not this.

1:52

That is the origin of the rectus femoris

1:55

from the anterior inferior iliac spine.

1:58

It will also have a small origin

2:00

from the anterior acetabular roof,

2:02

which we don't see here as yet.

2:05

But there are the medial and lateral portions of

2:09

the anterior capsule which form the letter Y.

2:13

Here's one limb of the Y,

2:15

here's the other limb of the Y.

2:16

They come down and merge as the

2:18

powerful iliofemoral ligament.

2:20

That little tiny gray slit is the pre-

2:24

labral recess, which may fill with fluid.

2:27

Sometimes this ligament is referred

2:28

to as the ligament of Bigelow.

2:31

The sagittal projection invaluable on its

2:34

own in 20 percent of all labral tears.

2:39

Let's go to our water-weighted fat-

2:41

suppressed image where we see the inferior

2:44

capsule forming the inferior boundary of

2:47

the intra-articular portion of the femur.

2:50

This is important because fractures above

2:52

this level may lead to necrosis, and fractures

2:55

below this level have a better prognosis.

2:58

So you should get in the habit of being

3:01

able to identify where the capsule is.

3:04

This inferior transverse structure,

3:07

not coincidentally, is known

3:08

as the transverse ligament.

3:10

It is said to produce the appearance

3:13

of a Saint Andrew's cross.

3:15

I don't see it.

3:16

There is another thin structure right here,

3:21

which can be confused with a piece of capsular

3:24

anatomy. But it is a pectinosynovial fold.

3:28

It is a variation, a type of synechiae

3:32

or plica, analogous to the one I showed

3:34

you earlier in the paralabral region.

3:38

So in the sagittal projection, we don't

3:41

want to see any signal going longitudinally

3:44

in our labrum or through our labrum.

3:45

And unfortunately, in this case, we do in one

3:49

small locus, right there, a young individual

3:52

with signal going through the labrum,

3:55

although ill-defined—an abnormality, a

3:58

labral tear in a high-performance athlete.

4:01

We want to see a firm, complete black

4:04

triangle, like we see on the far right,

4:07

with no defects from back to front,

4:09

and no defects running longitudinally.

4:14

Let's move on now to the

4:16

beloved coronal projection.