0:00

So on your left, the sagittal water sensitive PD spur.

0:03

T1 fat-weighted anatomy image in the middle,

0:06

and the T2 spin echo on the right.

0:10

I have intentionally provided a scan with

0:13

a little bit of quadriceps inflammation,

0:16

showing exaggerated striations.

0:18

Now these exaggerated striations are related

0:22

to fluid between the interstitial fibrils or the

0:27

insertional fibrils of the subgroups

0:29

that make up the quadriceps.

0:31

So it's a multi-layered structure.

0:33

And what's it made up of?

0:35

The rectus femoris in the front,

0:38

the vastus medialis and lateralis in the mid lateral

0:43

and mid medial portions of the quad.

0:45

And then the VIO,

0:46

the vastus intermedius is the deepest layer.

0:50

So you can separate the layers,

0:52

you can perpendicularly tear a superficial

0:54

layer, like the rectus.

0:56

You can go halfway through or 3/4 full and get 2 or 3 layers,

1:00

or you could get the whole thing in which case it retracts,

1:04

you can tear it and separate it here.

1:06

You can take a piece of bone with it,

1:08

and the striated appearance is very apparent

1:10

down low as you approach the patella.

1:13

Now, the continuation of the quadriceps across the

1:17

patella is seen, perhaps better, as the union of

1:21

the pre-patellar plate and the cortex in front.

1:24

You've already learned that there are three separate bursa layers

1:28

here that can lead to fascial degloving

1:30

or Morel-Lavallée syndrome.

1:32

Patient has a small traction spur anteriorly.

1:35

Now, what is continuing over the patella ee articulated earlier

1:41

is just the rectus layer or the most superficial layer.

1:46

The deeper layers, namely the VMO, the VLO,

1:49

and the VIO drop out.

1:51

Then this continues on as the patellar tendon,

1:54

which has a slight slope from anterosuperior

1:58

to posteroinferior. Therefore, it's prone to magic angle effect

2:03

or in other words, higher signal on short TE sequences

2:07

that go away on the T2-weighted image

2:09

or if the patellar tendon is a little wavy at each site

2:12

where there's a little wave,

2:14

the tendon may appear a little bit gray.

2:16

Then it inserts on the tibial tubercle.

2:20

Above, we see the reflected fat pad,

2:24

which is a site of potential impingement.

2:26

We have an infrapatellar fat pad,

2:29

which is another site of potential impingement.

2:33

We'll teach you a little bit later on how to use the PD spur,

2:36

the T1 and the T2 to recognize

2:39

and to properly named abnormalities

2:42

of all tendons.

2:43

But especially the quadriceps tendon.

2:46

Let me turn my attention with you now to the axial projection.

2:49

I'm up above the patella, right near the insertion

2:53

and now we see vertical striations.

2:57

And this is common

2:59

and the interdigitation between the rectus femoris,

3:04

the VIO,

3:05

the VMO and the VLO, is not so apparent

3:07

as it is in the sagittal projection.

3:10

But you could tear on one side or the other side,

3:13

you could tear partial thickness,

3:15

or full thickness,

3:16

you can tear vertically and separate the tendinous

3:19

way or you could tear horizontally, a so-called

3:22

delamination tear that separates

3:25

the individual muscle bundles.

3:28

The depth of the tear is measured this way.

3:31

The length of a tear of the quadriceps is

3:34

measured this way from side to side.

3:36

So you could,

3:37

you could tear all the way through on this side,

3:40

you would have a full thickness, yet incomplete tear.

3:44

You could have a delamination tear in

3:46

the superficial layer and the mid layer or

3:49

in the deep layer running side to side.

3:51

Now, a little bit more anatomy.

3:53

On the lateral side is the vastus lateralis and the VLO tendon.

3:59

We also have the continuation of the quadriceps as the

4:03

quadriceps retinaculum, which contributes

4:06

to layer 2 of the anterior LCL.

4:11

Let's look at the coronal projection now.

4:14

We're very far anterior and we see the quadriceps

4:17

tendon layering out. In other words,

4:20

fanning out from side to side.

4:22

We see a continuation of it as the lateral quadriceps retinaculum

4:28

merging with the parapatellar retinaculum.

4:31

And although not seen in this projection,

4:33

the vastus lateralis oblique is tendon.

4:36

There you see it again on a more posterior slice.

4:39

The retinaculum and continuation of the quadriceps tendon,

4:43

forming part of the parapatellar retinaculum.

4:47

Remember that the quad contributes to layer two

4:50

of the lateral collateral ligament complex.