A manual of diseases of the ear / by George P. Field.

  • Field, George P (George Purdey)
Date:
1893
Catalogue details

Licence: Public Domain Mark

Credit: A manual of diseases of the ear / by George P. Field. Source: Wellcome Collection.

Provider: This material has been provided by The University of Leeds Library. The original may be consulted at The University of Leeds Library.

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    There is one row of hair-cells on the inner side of the rods of Corti, and three or four on the outer side. Possibly the feet of the cells are prolonged deeply until they come in contact with the ending of a filament of the auditory nerve, in the same way that the olfactorial cells, described by Schultze, dipping down into the Schneiderian membrane, are supposed to join with the filaments of the olfactory nerve. The vestibular scala is subdivided by the membrane of Eeissner, which stretches from the upper layer of the lamina spiralis to the outer wall of the cochlea. This small additional gallery thus lies between the membranes of Corti and Eeissner; it is called the canal of the cochlea. Ellis describes it as closed above near the tip of the cochlea, and as communicating below by a very small tube with the cavity of the saccule, a small, bladder-like body, Avhich is lodged in the fovea hemispherica of the vestibule. The vestibule is lined throughout by a delicate fibrous tissue, which is by one surface in firm connection with the bony wall, whilst on the other it is covered with a layer of cells of squamous epithelium. It is this membrane which closes in, with the help of the base of the stapes, the foramen ovale. From the vestibule the lining is continued throughout the semi- circular canals, whilst it enters the uppermost gallery of the cochlea (scala vestibuli) through the apertura scalte. This gallery it lines throughout, up to the very top, and thence it passes through the gap left by the ending of the lamina spiralis (heliocotrema) into the lower gallery, the scala tynipani. At the bottom of this scala it ends, blocking up the fenestra rotunda. So the osseous labyrinth is lined throughout with a libro-serous membrane. The office of the membrane is to secrete a watery fluid, the perilymph. The perilymph of the vestibule has floating in it a bladder which is several sizes smaller than the bony chamber itself, and tubular ]jrolongations run backwards from this through the horse-shoe canals. The prolongations swell out in the ampulke. From their being so like the osseous labyrinth in shape, the bladder and its semicircular processes are called the membranous labyrinth. This is covered on its inner side throughout by a