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Let's look at this patient's CT scan presented

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with congenital sensory neurohearing loss.

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Our approach is always going to be to start

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from the outside, working inward.

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So we're going to look at the external auditory

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canal, and in this example, we have a nice

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cartilaginous external auditory canal.

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We have a nice bony external auditory canal

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so we can clear the external ear.

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Even the helix looks pretty good.

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And then we come to the middle ear ossicles, and we

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have our ice cream and ice cream cone, and we have

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the parallel lines of the neck of the malleus

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and the long process of the incus.

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And we come down to the oval window.

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Well, at the oval window, we have sort of a bony atresia of

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the oval window, and we see this unusual appearance

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to the vestibule. As we look at the vestibule,

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we also look at the cochlea next to it, and

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we see this bulbous appearing cochlea.

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There really is no meiosis to this cochlea.

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And as opposed to some of the cases where

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we could clearly identify a basal turn,

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in this case, there really hasn't been any

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development of any of the turns, and this eventually

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communicates with the dilated vestibule here.

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So we have an example of both cochlear and

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vestibular abnormality that are cystic and enlarged.

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So our cystic cochlear vestibular structure,

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in this case, we have some separation between

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the cochlea and the vestibule.

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But as we look at this very enlarged vestibule,

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we also notice that there's pretty poor development

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of the lateral semicircular canal.

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It's not making that good turn, and it's

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coming to a big dilated portion here.

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And as we go even further superiorly,

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we notice that there's a dilated anterior limb of

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the superior semicircular canal and really poor

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development of the posterior semicircular canal.

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In this example,

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we would be concerned about the communication here

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between a poorly developed cochlea and vestibule

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as an incomplete partition type.

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One example we note that the internal auditory canal

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is normal, and we will then proceed to the MRI scan

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to make sure that the patient has a normal cochlear

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nerve before suggesting any intervention.

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This is the contralateral side, and once again,

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we have poor development of a cochlea.

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We have the vestibule, but

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it's dilated and has poor development of the

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semicircular canals in this example as well.