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MICROTIA AND CONGENITAL MEATAL ATRESIA

J. S. FRASER, M.B., F.R.C.S.

Arch Otolaryngol. 1931;13(1):1-27.

	Since this article does not have an abstract, we have provided the first 150 words of the full text PDF and any section headings.

Before dealing with maldevelopments of the external and middle ear, it is advisable to give a short account of the normal development of these parts. According to Young and Robinson, the visceral or pharyngeal clefts and arches are due to outward linear pouchings of the entoderm. The first cleft is the best marked. Its inner or medial part is converted into the eustachian tube and tympanum, while its outer or lateral part becomes the external auditory meatus. The membrane that lies at the bottom of the cleft consists at first merely of ectoderm and entoderm, but in a short time a thin layer of mesoderm is insinuated between the two and so the tympanic membrane is formed. The floor of the first cleft is thus transformed into the drumhead.

The margins of the visceral clefts are also thickened by the ingrowth of the mesoderm between the entodermal and ectodermal layers. . . . [Full Text PDF of this Article]

Author Affiliations
EDINBURGH, SCOTLAND

From the Laboratory of the Royal College of Physicians, Edinburgh.

Footnotes
Submitted for publication, July 15, 1930.

The Carnegie Trust of Scotland contributed toward the cost of providing illustrations for this paper.

A short preliminary account of this work was published in the Proc. Roy. Soc. Med. (Otol. Sect.) 22:85 (March) 1929.

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