This Ear Looks Different

Discussion The tympanic membrane has two parts, the pars flaccida and the pars tensa. Each has 3 major layers: an external keratinizing squamous epithelial layer, a central connective tissue layer, and an internal epithelial layer. The pars flaccida connective tissue layer is less well-organized than the pars tensa. Learning Point Normally, there is a centripetal migration of the keratinocytes from the central part of the tympanic membrane (along the malleus) outward to the periphery. An india ink stain of this process can be seen here. The cell migration outward is slow to begin with (i.e. new cells stay near the central area for several weeks) then as they move toward the periphery the migration speed increases. This can easily be seen in keratin patch formation. Keratin layers split during the migration forming patches similar to ice flows or the well-demarcated spots on a giraffe. An image can be seen here. Tympanic membrane perforations also appear to heal in a similar way, by the movement of keratinocytes from the malleus area to the periphery as one of the initial activities. Repair of the other layers seems to follow for the tympanic membrane. Most acute perforations heal spontaneously, but others may not causing chronic perforations which are associated with ear discharge, recurrent infections, conductive hearing loss, speech and language delays and cholesteatomas. Chronic supprative otitis media is also increased with chronic perforations and is associated with oth...
Source: PediatricEducation.org - Category: Pediatrics Authors: Tags: Uncategorized Source Type: news