0:00

So let's look at some examples

0:02

of normal infant spine ultrasounds.

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Let's look at what normal anatomy looks like.

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So the corns meis, so the tip

0:09

of the spinal cord is the blue arrow structure there.

0:13

It should be triangular in shape.

0:15

It should never be blunted,

0:16

and it really shouldn't be elongated either.

0:19

The orange arrow is pointing to the nerve rootlets

0:22

of the kata equina.

0:23

The CSF is indicated by the green arrows.

0:26

And then you can see your vertebral bodies at the

0:28

anterior aspect of the image.

0:29

Again, we image from posterior to anterior

0:33

a magnified view looking at the, um, conus, meis itself

0:37

and the inferior cord.

0:40

So the asterisk is showing you the hypoechoic spinal cord.

0:44

The purple arrow is showing you a normal

0:47

central append canal,

0:49

and that's allowed to be up to two millimeters in thickness.

0:52

Um, it is normal to see some transient dilation of

0:54

that central penal canal.

0:56

The conus mellis itself is that again, triangular shapes tip

1:00

of the spinal cord.

1:02

The orange arrow is again pointing

1:04

to the nerve rootlets of the kata equina.

1:06

The dorsal surface of the cord is indicated

1:10

by the yellow arrow here.

1:11

If that was at the anter aspect,

1:12

it would be the ventral surface of the cord.

1:15

And then the green is showing you the subarachnoid space

1:17

of CSF fluid surrounding the conus and nerve rootlets.

1:22

So let's focus on the conus mellis itself.

1:25

So again, the conus should be nice and triangular shaped.

1:28

It shouldn't be blunted or rounded in appearance

1:30

and it shouldn't be elongated in appearance.

1:33

The, uh, normal termination point of the conus mellis is,

1:38

uh, above the L three vertebral body level.

1:42

So it's allowed to touch the L three vertebral body level,

1:44

but it can't extend beyond the, the upper one third

1:48

of the L three vertebrae in a preterm infant.

1:51

We know that the, the cord in development extends inferiorly

1:55

and as the baby progresses throughout development,

1:57

throughout embryologic uh, development,

1:59

the cord a sends normally over time.

2:02

And so if you have a premature infant that you have imaged

2:05

very premature, you might consider just documenting that

2:09

that normal ascension has occurred over time

2:13

to make sure you don't have a low lying conus mellis.

2:16

But how do you tell what level you're at?

2:18

So how do you know you're at that?

2:20

The conus is at the L three vertebral body.

2:22

So there are several ways to tell what level

2:25

of vertebral body, uh, the conus mellis is at

2:28

the most consistent.

2:30

And probably the best way to tell is

2:32

by looking at the lumbosacral junction.

2:35

So you take in your mind's eye

2:37

or on your pacs, you take a line that is parallel

2:39

to the lumbar spine vertebral bodies,

2:42

and then you take a line that is, uh, parallel

2:44

to the sacral vertebral bodies.

2:46

And where they intersect is the lumbosacral junction.

2:49

And this is where it might be helpful again

2:51

to place a towel, a rolled towel underneath the pelvis

2:54

to kind of accentuate that lumbosacral junction to be able

2:57

to tell where is

2:58

The L five vertebral body

3:00

and then you count up from there.

3:01

So in this patient, the lumbosacral uh, junction is here.

3:05

So this is 5 4 3 2.

3:06

So this conus mellis ends at about L one slash L two.

3:11

We do have a little bit of obscuration from the spinous

3:13

process obscuration here.

3:15

Another way to confirm, uh, vertebral body level is

3:19

to count from the inferior most rib.

3:22

Now you can imagine that this is not gonna be consistently

3:25

accurate because you can have variable ossification

3:28

or presence of the 12th rib, but if you can see a 12th rib

3:31

and then count five uh, vertebral body levels below that,

3:35

you follow that rib in the sagittal plane from

3:38

lateral to medial.

3:39

Um, until you can see this is the T 12 vertebral body.

3:43

So this would be L one, this would be L two.

3:45

This conus mellis ends at the superior aspect

3:48

of the L two vertebral body.

3:50

Again, there's variable ossification

3:52

of the inferior most rib.

3:53

And so this is a little bit less accurate.

3:57

Don't forget that if you are looking from sagittal

4:00

to medial, you might encounter some unexpected

4:03

abnormalities, the most common

4:04

of which is gonna be hydronephrosis.

4:06

We have a whole section on genital urinary imaging

4:09

where we'll talk about how to grade this and what to do

4:11

after you've found neonatal hydro necrosis.

4:14

But don't forget to look at the paraspinal soft tissues

4:17

as you are imaging the spine because you can see them.

4:21

Okay, another way to tell

4:23

what vertebral body level you are out to be able

4:25

to count levels or appropriately labeled the lumbar

4:29

and sacral vertebral bodies is the shape

4:32

of the sacral vertebral body compared

4:34

to the cox vertebral bodies,

4:36

the sacral vertebral bodies will have a square

4:39

or rectangular shape.

4:40

So this uh, pink arrow is pointing to a square shaped

4:45

sacral vertebral body.

4:46

The cox is going

4:47

to be variably ossified depending on the gestational age

4:51

of the infant and the development of of the infant.

4:54

But the coxal vertebral bodies

4:56

as they ossify are not gonna be square or rectangle,

4:59

but they're gonna be round or triangular

5:01

or sort of irregularly shaped.

5:03

So, um, you can sort of tell the inferior,

5:06

most sacral vertebral body is S five is going

5:09

to be square in shape.

5:11

The coil segments will be either un ossified

5:13

or have a weird little round

5:15

or triangular ossification center.

5:17

Um, in them. This is a just a, a second example

5:21

where we have a square shaped inferior S five

5:24

or the fifth sacral segment that is ossified.

5:27

And then we have this tiny little dot

5:29

of irregularly shaped coil ossification.

5:32

So that's our anatomy on the sagittal plane.

5:34

Let's go to our, uh, transverse plane

5:36

where normal anatomy looks very similar

5:39

just in the transverse plane.

5:41

So our yellow arrows are pointing to the, um, lamina

5:44

of the posterior arch of the vertebral body.

5:47

You can see paraspinal structures.

5:49

So the blue arrows are pointing to normal neonatal lung.

5:53

The vertebral body itself is indicated

5:55

by this purple arrow. And so the

5:56

Cord is going to be this orange structure

5:59

with nerve rootlets, um, alongside of it.

6:01

And that's gonna be surrounded by a normal an coic CSF.

6:04

So this is the thoracic spine level

6:07

and the transverse plane.

6:08

And as you go inferior,

6:09

of course the paraspinal soft tissues are going

6:11

to change the nerve.

6:13

Rootlets should be dependent, they should fall with gravity.

6:16

So if you have an infant who is in the prone position,

6:18

they should be located anteriorly.

6:21

You can see your central spinal lap, penal canal,

6:23

and then the cord itself is um, indicated

6:26

by the orange arrow.

6:27

The paraspinal musculature in this,

6:29

in this image is indicated by the yellow arrows.

6:33

Again, your cord should fall dependently.

6:36

So if you have an infant who is in the prone position,

6:38

the cord and nerve rootlets should fall

6:40

with gravity anteriorly.

6:42

If you're imaging a patient who is in the decubitus position

6:45

or is being held upright by their caregiver, um, the cord

6:49

and nerve rootlets should go appropriately

6:51

with gravity depending on patient positioning.

6:53

Normal, if you have a prone infant, the cord

6:56

and nerve rootlet should be located in the anterior aspect

6:59

of that spinal uh, canal.

7:02

Um, even more inferiorly.

7:04

Now we are below the level of the conus mellis.

7:07

We're at the level of the phylum terminality.

7:09

So we're at the inferior lumbar spine level.

7:11

In the transverse plane.

7:13

Again, we have the lamina, the um, bony genic,

7:16

lateral posterior elements.

7:18

We have our normal, um, nerve rootlets of the coquina.

7:22

And then we have nice normal, uh,

7:24

anti coex ESF in the subarachnoid space.

7:26

And you can sort of see a little bit

7:28

of vertebral body anteriorly.

7:30

Mostly we get shadowing related to the bony cortex of

7:33

that lumbar spine vertebral body.

7:36

And at the level of the sacrum, all

7:38

of the nerve rootlets should be clumped anteriorly

7:40

or fall with gravity.

7:42

They should move with motion.

7:43

And then we should have koic CSF, just

7:46

because most of you are probably more familiar with MRI.

7:50

Here's an MRI comparison of

7:51

what the ultrasound looks like in the panoramic view here on

7:54

the left compared to a T one weighted MRI compared

7:58

to a T two weighted MRI.

7:59

So it looks basically the same

8:01

as just different shades of gray.

8:03

Again, I tell my residents,

8:04

pretend you're looking at an MRI,

8:06

but you get to see motion even better.

8:08

Um, and you can image for as long as you want without having

8:11

to worry about, um, concerns with sars.

8:13

So your specific absorption rate with MRI or heating

8:16

or the patient waking up and moving,

8:18

because with ultrasound you can chase them

8:19

around as long as you want.

8:21

Again, just to compare our conus, meis is that blue arrow

8:24

where you can see best on the T two weighted, um,

8:27

or ultrasound.

8:28

The nerve rootlets of the ca aquinas should not be clumped.

8:31

They should move like seaweed flowing in the breeze

8:34

on our cinematic images.

8:35

And then we should have koic, uh,

8:38

CSF in the subarachnoid spaces.

8:39

So just a comparison with MRI,

8:41

which you might be more familiar with in the sagittal plane.

8:44

And here we are in the transverse plane.

8:46

So in the axial image

8:47

or transverse plane at ultrasound, again comparing to MRI,

8:50

which maybe you will be more familiar with, I have

8:53

to tell you the axials are flipped.

8:54

And so in this patient, this patient was imaged supine

8:58

and that's why everything looks like it's in the dorsal

9:00

aspect of the cord because that's how it falls with gravity.

9:03

At MRI when you're imaging them supine at ultrasound,

9:06

the vast majority of the time we're gonna image them prone.

9:09

So the uh, cord coquina, uh,

9:12

nerve rootlets should fall anteriorly with gravity.

9:16

The money sometimes is gonna be your cinematic images.

9:19

So, um, when you have a movie

9:20

and you're able to see not only uh, movements

9:24

of the cord, uh, conus meis

9:27

and nerve rootlets of the coquina,

9:29

they should move like seaweed flown in the breeze

9:33

or, uh, you know, the, the sea, the sea currents.

9:36

Um, and that's because they're not tethered.

9:38

They're freely moving not only with respiration

9:40

but with cardiac pulsation.

9:41

So this is a nice normal conus mellis nerve rootlets.

9:45

And then this is our phylum terminality that, um,

9:47

is not thickened.

9:49

It's smaller than two millimeters,

9:50

and it also moves with breathing cardiac pulsations

9:54

and any little patient movements.