0:00

So switching gears more towards the shoulder.

0:02

So we're a little distal to the brachial plexus.

0:04

We're gonna talk about the suprascapular nerve next.

0:07

This is one that you'll certainly see in all

0:09

of your shoulder MRIs, uh, and be looking for it.

0:11

Even if you're looking, you know, specifically

0:13

for rotator cuff tear.

0:14

The more you get familiar with these, uh,

0:16

imaging structures on other uh, you know, exams,

0:20

the easier it will be when you're asked to identify

0:22

for potential, uh, nerve entrapment case.

0:25

So our suprascapular nerve innervates predominantly the

0:28

supraspinatus and infraspinatus muscles.

0:30

And remember it has that unique course going over this notch

0:33

in the scapula right at the neck,

0:35

and then it kind of divides

0:36

and it goes a branch into the supraspinatus adjacent to

0:40

that spinal glenoid notch

0:41

and then a branch into the infraspinatus muscle.

0:46

So those are the two major sites of impingement as well,

0:49

that suprascapular notch and that spinal glenoid notch.

0:52

Now because if you have a more proximal entrapment,

0:55

you're actually gonna affect both muscles

0:57

and have this pattern of

0:59

denervation where both are involved.

1:00

If you have a more distal impingement syndrome,

1:03

you're really just gonna take out that infraspinatus branch,

1:06

so you'll have isolated infraspinatus muscle atrophy.

1:09

Uh, the most common cause,

1:10

and one that we should all be familiar

1:11

with are large paralegal cysts.

1:13

Um, you can have traumatic injury

1:15

of the nerve in this region as well

1:16

and some anatomic variation that can cause compression.

1:20

But certainly most common is that labral pathology.

1:24

So let's look at a case of

1:25

Superscapular nerve syndrome, right?

1:27

This is a 41-year-old woman

1:29

and she had had some pain in her shoulder

1:30

after weightlifting.

1:32

They did actually an EMG in this particular case,

1:34

which confirmed that she had some abnormality in those

1:37

muscles, uh, concerning for a suprascapular nerve injury.

1:41

So I have fluid sensitive sequences here in both the coronal

1:44

and the sagittal plane, as well as some selected, um, uh,

1:48

ultrasound images as well as a,

1:50

a surgical correlation picture here.

1:53

And you'll note right off the bat, starting

1:55

with those secondary imaging findings,

1:57

there's some abnormality of that infraspinatus muscle.

2:00

It's small. Look at how small it is in comparison

2:03

to arteries, minor muscle,

2:04

and it's also increased in signal.

2:06

So if I take off that color overlay, you'll note

2:08

that it has a little bit of, uh, um,

2:11

relative fluid intensity increase in signal compared

2:13

to the adjacent musculature.

2:15

So then we're gonna identify the course

2:17

of our suprascapular nerve.

2:19

We know it likes to hug this posterior aspect

2:21

of the glenoid on its way to the spine of the scapula.

2:25

And that is right where we have a paralabral cyst.

2:28

So the yellow arrow kind of denotes the course of

2:30

that suprascapular nerve.

2:31

And then we see this large cystic structure.

2:33

When we scrolled through the image, we could see that

2:35

that was associated with a labral tear.

2:37

Uh, and this was a case

2:38

of a paralabral cyst causing some entrapment of

2:41

that suprascapular nerve.

2:42

Uh, nice arthroscopic correlation, just seeing

2:45

that cystic structure in that general space, as well

2:48

as the gray scale ultrasound images.