Auditory epithelial migration on the human tympanic membrane: II. The existence of two discrete migratory pathways and their embryologic correlates

Abstract

The pathways of movement of dye-markings on the tympanic membranes of 30 ears of 15 volunteers were investigated by photography with a Hopkin's rod. Two discrete pathways were identified. Movement on the pars tensa was centrifugal in all directions from the edge of the handle of malleus surface. This supported our previous suggestion that pars tensa epithelial migration is based on growth of the meatal plate. Movement on the more central part of the handle surface itself, however, was always upwards to the pars flaccida epithelium and then, with all dye on the latter, in a posterosuperior direction only. The covering epithelium of the pars flaccida/handle of malleus arises from the fundus of the early embryonic external canal. To explore the possibility that its migration may also commence early, the fundus was examined histologically in 12 embryo ears. It was shaped like an inverted pear to conform to the primordial head of the malleus above and its handle below. There was distinct flattening of the whole fundal epithelium in contrast to the side wall of the external canal, lending support to the concept of a primordial flux of epithelium in the main fundus and its inferior extension. The meatal plate grew from the rim of the fundus producing the pars tensa and deep external canal epithelia. This process, however, was not associated with significant cytologic alterations or increased expression of the human proliferation antigen, Ki-67, at that rim. This suggests that the pars tensa epithelium grows and moves without the active involvement of the epithelium of the pars flaccida/handle of malleus.

Auditory Epithelial Migration III: An Immunohistologic Study Using Anti-Brdu Antibody on Tympanic Membrane in Mouse

“…[4][5][6][7] We have therefore reported on patterns of the auditory epithelial migration (AEM) in the rat visualized by means of a dye marking technique. 8 This species shows almost the same pathway patterns as found in the human.…”

“…8 This species shows almost the same pathway patterns as found in the human. [4][5][6][7] Due to this fact, we consider the rat one of the most useful experimental animals for studies of the human type of AEM.…”

Auditory epithelial migration. III. development of the stratified squamous epithelium of the tympanic membrane and external canal in the mouse

“…Zone 1 was found to move as a separate pathway in our human dye-marking study (Michaels and Soucek, 1990). We suggested there that migration in this zone may arise early in development, C .…”

“…1, fundus of primary external canal; 2, epithelium on medial surface of meatal plate; 3, epithelium on lateral surface of meatal plate; 4, epithelium of side walls of primary external canal. Reprinted from Michaels and Soucek (1990). handle of the malleus (HM), and its lateral aspect the adjacent deep canal. The epithelium of the side walls of the primary external canal developed into that of the cartilaginous canal, referred to as zone 4 in the human.…”

Pathologie de l’oreille

“…Cette armature fibreuse est tapissée à sa face latérale (vers le CAE) par un revêtement malpighien sans annexes dont les cellules migrent de façon centrifuge et ne desquament qu'arrivées en périphérie du tympan [2]. Sa face interne est recouverte d'une muqueuse très fine, à épithélium cubique qui se continue avec celui de l'oreille moyenne.…”