Volume 2

Manual of practical anatomy / by D.J. Cunningham.

  • Cunningham, D. J. (Daniel John), 1850-1909.
Date:
1903
Catalogue details

Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0)

Credit: Manual of practical anatomy / by D.J. Cunningham. 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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    The posterior wall of Ihe tympanum shows the iter chorda; posterius, the pyramid, and the opening into the mastoid antrum. The mastoid antrum is roofed over by a thin plate of bone termed the legmen tympani. The acute bend in the aqueduct of P^allopius, which corresponds to the geniculate ganglion of the facial nerve, has been cut across, showing the canal divided in two places. On the cut surface of the opposite part of the bone (not figured) several turns of the cochlea will be found to be cut across, and the communication of the bend of the aqueduct of Fallopius with the hiatus Fallopii will be seen. On the same piece of bone the student should also note the canal for the tensor tympani, which is situated immediately above the processus cochleariformis, and the Eustachian tube, which lies below that thin bony lamella. He should pass a pin through the Glaserian fissure, and in this way ascertain its internal opening. Immediately Opening of superior and posterior semi- T ' circular canals into vestibule ; Superior semicircular canal Fovea henii- elliptica' Aqueduct of Fallopius Cochlea- Carotid canal, External semi- circular canal Aqueductus vestibuli Posterior semi- circular canal Aqueduct of Fallopius f ovea neniispnerica B'IG. 220.—Vertical section of the Left Temporal Bone the superior border of the petrous bone, and about of an inch anterior to that border. parallel to one-ei£rhth external to that opening he will find the continuation of the ridge for the membrana tympani. ,.,.,.„. Section II.—The parts in this section are exhibited in i^ig. 219. ine superior and external semicircular canals are divided, and their ampulla; are shown. The middle portion of the aqueduct of Fallopius is laid open, and the two bends of that canal are seen. Just in front of the posterior bend is the opening of the pyramid. The pyramid is connected to the promontory by a little spicule of bone, which has been compared to a flvine buttress (Holden). The promontory forms a bold eminence on the inner wall of the tympanum. Above it, is placed the fenestra ovalis ; below and behind it, is the fenestra rotunda. The latter opening is somewhat under the shadow of the promontory. Section III.—In the section from which tig. 220 is taken, the saw has passed through the cochlea and the vestibule, the superior and external semicircular canals, and the first and third parts of the aqueduct of Fallopius The modiolus or axis of the cochlea is cut transversely near its base If llie specimen be held up to the light and examined w-ith a pocket-lens, the modiolus will be seen to be pierced by a number of fine