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External auditary canal atresia
In external ear atresia the external auditory canal is not developed and sound cannot reach the tympanic membrane. A conductive hearing loss is the result.It is important to note whether the atretic plate is composed of soft tissue or bone. The extent of ossicular chain malformation can vary from a fusion of the mallear head and incudal body to a small clump of malformed ossicles, which is often fused to the wall of the tympanic cavity. The mastoid portion of the facial nerve canal can be located more anteriorly than normal and this is important to report to the ENT surgeon in order to avoid iatrogenic injury to the nerve during surgery.
On the right a 2-year old boy with left bony external auditory canal atresia. The malleus and incus is fused . The cochlea is normal.
In external ear atresia the external auditory canal is not developed and sound cannot reach the tympanic membrane. A conductive hearing loss is the result.It is important to note whether the atretic plate is composed of soft tissue or bone. The extent of ossicular chain malformation can vary from a fusion of the mallear head and incudal body to a small clump of malformed ossicles, which is often fused to the wall of the tympanic cavity. The mastoid portion of the facial nerve canal can be located more anteriorly than normal and this is important to report to the ENT surgeon in order to avoid iatrogenic injury to the nerve during surgery.
On the right a 2-year old boy with left bony external auditory canal atresia. The malleus and incus is fused . The cochlea is normal.
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