The anatomy and physiology of the organ of hearing; with remarks on congenital deafness, the diseases of the ear, some imperfections of the organ of speech, and the proper treatment of these several affections / By David Tod.
- Tod, David
- Date:
- 1832
Licence: Public Domain Mark
Credit: The anatomy and physiology of the organ of hearing; with remarks on congenital deafness, the diseases of the ear, some imperfections of the organ of speech, and the proper treatment of these several affections / By David Tod. Source: Wellcome Collection.
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![Each of these canals is of an oval form, and large enough to contain a piece of packthread. They each constitute upwards of three-fourths of a circle. Their conical dilata- tions are called Cavitates Elliptice. The Cochlea is situated obliquely at the anterior and internal part of the Vestibulum, in such a manner as to have its basis towards the bottom of the Foramen Audi- tivum Internum, and its apex nearly opposite to the en- trance of the Eustachian Tube into the Cavitas Tympani, but a little above it. Its figure resembles the shel] of a garden snail, is broad at its Basis and narrow at its Apex, and forms two Turns or Gyrations, and a little more than a half, round a Newel, or Central Pillar. The First Turn is next the Basis, and is about two- thirds larger and wider than the Second, which becomes suddenly smaller. The Second Turn is anterior to the First, and is about half larger and wider than the remain- ing portion, which also becomes suddenly smaller, and terminates in an apex or point called the Cupola. The First Turn is not all of one diameter, for in its course it becomes progressively smaller: the same ap- pearance is obvious in the Second, and their twistings ac- count for the sudden smallness which takes place in the Turns. The Turns are each divided by a Spiral Septum into two canals called Scale, from their supposed resemblance to a staircase. This Septum is composed partly of bone and partly of membrane. ‘The osseous portion is the smallest; it is placed next the central pillar, and called Septum Scales or Lamina Spiralis; the membranous is placed next the shell of the Cochlea, and called by Vatsatva Zona ~ Cochlee. 'This last is only seen in the recent subject, and its apparent use is to assist in preserving the sentient mo- tion of the dqua Labyrinth. The Septum Scale commences a little from the basis, and winds round the central pillar until it nearly reaches](https://iiif.wellcomecollection.org/image/b33094019_0049.jp2/full/800%2C/0/default.jpg)
