Human osteology : comprising a description of the bones ; with delineations of the attachments of the muscles, the general and microscopic structure of the bone and its development : to which is added a brief notice of the unity of type in the construction of the vertebrate skeleton / by Luther Holden.

  • Holden, Luther, 1815-1905.
Date:
1857
Catalogue details

Licence: Public Domain Mark

Credit: Human osteology : comprising a description of the bones ; with delineations of the attachments of the muscles, the general and microscopic structure of the bone and its development : to which is added a brief notice of the unity of type in the construction of the vertebrate skeleton / by Luther Holden. Source: Wellcome Collection.

Provider: This material has been provided by Royal College of Physicians, London. The original may be consulted at Royal College of Physicians, London.

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    scribes a slight curve with the concavity downwards. Besides this general ciu-ve, the cartilaginous part is slightly curved with the concavity forwards, and the osseous part with the concavity back- wards. Altogetherj the meatus has such a curious shape that it cannot be well understood without looking at a cast of it. Of many which I have before me, no two are precisely similar in shape. Every surgeon knows how difficult it is to see the whole of the membrane of the tympanum at one view: one can seldom see more than a part of it, however much the ear be dilated and pulled so as to straighten the outer curve. The narrowest part of the meatus is about the middle. Beyond this point we ought not to introduce the speculum. Insects sometimes find their way down the meatus and cause intense pain. I will adduce an instance related by Wilde*, if only to show how to dislodge them: I remember being out shooting with a friend, who, suddenly exclaiming 'Oh, an earwig!' and throwing aside his gun, fell on the groimd, making the most piteous groans, and rolling about in agony. Suspecting that some insect had got into his ear, I procured some water from a ditch, and poured it into the meatus. While watching the result, a little animal, well known among anglers as the havrthorn fly, crept out, and my friend was instantly relieved. Membrana The membrana tympani is a thin, semi-trans- TTMPANi. parent, fibrous membrane, of a greyish colour, placed very obliquely at the bottom of the meatus auditorius externus. Its direction is downwards, forwards, and inwards. The reason of this obHquity would seem to be to increase the extent of its surface; so that every wave of sound reflected down the meatus must fall upon it. Observation has shown that the perfection of the sense of hearing in mammals and birds bears a direct ratio to the obliquity and extent of this membrane. Its circumference, which is pretty nearly circular, is fixed into a groove.in the bone so fine that it might have been traced with the point of a needle (Plate XLVm. A, fig. 2). This groove, however, does not form-a complete circle : it is deficient at the upper part, where the mem- brana tympani is, more obviously than elsewhere, continuous with * Aural Surgery, p. 178.