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Well, this is a wonderful case of a patient who has bilateral temporal bone

0:06

fractures that we can learn a lot from.

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So as we look at the fracture on the right side,

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we see that the obliquity here is not exactly horizontal and it's not

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exactly vertical. So vertical, going like here; and horizontal, going like

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here. This is actually an oblique fracture and it's a comminuted fracture.

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The fracture crosses the mastoid portion of the

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temporal bone. It crosses into the tympanic portion of the temporal bone,

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which makes up the wall of the external auditory canal. And you can

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see, there's some obliquity here that's, kind of, pointing towards the sphenoid

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sinus. So you always wanna make sure that the sphenoid sinus is intact

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as well as the walls of the carotid artery. In this case,

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you can see that here is the plane of the fracture coming across.

0:54

And then right here, we enter the carotid canal. This is the petrous portion

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of the carotid canal, and you have a non displaced fracture.

1:04

But that does put the carotid artery at risk. Sometimes you'll see a

1:09

little bit of air that you see right here, this little black stuff,

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that's air in the petrous internal carotid artery canal, and that's secondary

1:18

to communication with the temporal bone fracture. Whenever we have a temporal

1:23

bone fracture, we're gonna be very careful and look at the middle ear

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ossicles. And as you can see here, this is the head of the

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malleus. I'm gonna try to magnify this a little bit more.

1:35

You shouldn't see a line across the head of the malleus. This is

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the malleus, this is the short process of the incus. This is a

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fracture; you can see the fracture plane going through the head of the

1:47

malleus, so ossicular fracture is present. However, as I mentioned, this

1:55

way of thinking of the fractures as horizontal, or vertical, or transverse,

2:02

or longitudinal, versus oblique, has been replaced by whether or not the

2:08

fracture goes through the inner ear structures. And as you can see in

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this patient, there is a fracture line crossing into

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the vestibule. This is the vestibule with the semicircular canals, and this

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is an otic capsule violating fracture. It goes into the vestibule,

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which is part of the otic capsule. You notice also that that part

2:40

of this fracture is actually crossing the posterior semicircular canal.

2:45

So otic capsule violating. This is useful because this patient is at risk

2:51

for developing dizziness as well as potentially a perilymphatic fistula.

2:58

Lots of things to think about. We've discussed the

3:01

orientation of the fracture. We've discussed the violation of the middle

3:05

ear ossicles. We've discussed the violation of the temporal petrous portion

3:11

of the carotid canal. We've discussed the violation of the otic capsule.

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Now let's look at the contralateral side, as if this wasn't bad enough.

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So here we are on the left side, and as you can see,

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we got a little bit of fluid down here in the mastoid air cells. Here

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we have an unusual feature. This fracture is violating

3:35

the jugular foramen. So we have a bony fracture fragment in the jugular

3:39

foramen. Here is our petrous internal carotid artery. We notice the fracture

3:45

line going into the petrous internal carotid artery, with again, the telltale,

3:50

arrow sign of newsome, a small droplet of air in the petrous internal

3:56

carotid artery, telling us that there's a fracture involving that petrous

4:00

internal carotid artery that communicates with the middle ear structures

4:04

or the other portions of the temporal bone.

4:08

Now looking at this case, what we see is

4:13

an example of widening of the space between the neck of the malleus and

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the long process of the incus. Now how do I know that this

4:27

is widened? Let me magnify this. Well, I'm looking at... We should normally

4:32

see two parallel lines representing the neck of the malleus and the long

4:37

process of the incus. Here we see the distance there, that to my

4:41

eye, is widened. How do I know that that's abnormal? Well,

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fortunately we have the contralateral side for comparison. Notice the spacing,

4:50

notice the distance between the neck of the malleus and the long process

4:57

of the incus on the right side, versus

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on the left side. So we can actually

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measure that. And on the right side, we're going to call it 0.707

5:13

centimeters. And on the left side, 0.12 centimeters. So effectively, half

5:25

a millimeter or less difference, but it's widened. And that is an indication

5:31

of disarticulation or dislocation of the malleus neck from the long process

5:41

of the incus. We would like to follow this all the way down

5:44

to the stapes, and look and make sure that there is good articulation

5:49

between the incudostapedial joint, which is seen here. The incudostapedial

5:53

joint is the joint which is most likely to have a disarticulation, but

5:59

very hard to see unless you're doing ultra thin section CT scan.

6:04

Now... Aha, what do we see here? A fracture which is going across

6:11

the cochlea. So otic capsule violating temporal bone fracture on the left

6:17

side, and it's just entering the vestibule. You notice that there is air

6:24

here in the vestibule, which shouldn't be there, this is usually fluid filled.

6:27

And we also have air in the cochlea. This is what's known as

6:32

pneumolabyrinth, which is one of the complications of an otic capsule violating

6:38

fracture. Here you can see the jugular bulb with the air in the

6:42

jugular bulb from the involvement of the jugular bulb by this fracture.

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Finally, we wanna make sure that we look carefully at the facial nerve

6:51

because this fracture is crossing to affect the facial nerve. Let's identify

6:58

the facial nerve here as the labyrinthine portion of the facial nerve,

7:03

and then this is the horizontal portion of the facial nerve.

7:07

And right here, you see that the fracture goes right into the facial

7:11

nerve canal on the left side. And we would worry about whether or

7:15

not the patient has a facial nerve palsy. Here's the descending portion

7:19

of the facial nerve, and here's where the facial nerve leaves the temporal

7:24

bone in the stylomastoid foramen. So intramastoid portion of the facial

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nerve, horizontal portion of the facial nerve, fracture plane right here

7:36

entering the facial canal in this portion of the facial nerve,

7:39

all of a sudden gets bulbous. Now compare the width here from the

7:43

width here. So I'd be concerned about the facial nerve being contused in

7:48

this location. So on the left side, otic capsule violating, also violates

7:54

the jugular bulb and violates the carotid canal. It leads to pneumolabyrinth.

7:59

We have separation and dislocation of the malleus from the incus. And we

8:05

have a contused left facial nerve tympanic segment, all associated with

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this comminuted fracture of the left temporal bone. Notice also that this

8:16

fracture enters the temporomandibular joint and that can lead to a hemarthrosis,

8:22

blood in the joint of the temporomandibular joint.

8:25

Very complex case, but you got it.