. Elementary physiology . Fig. 116.—View of the left membrana tympani and auditory ossicles from the inner side, and somewhat from above (E. A. S ). f 7n, malleus ; i, incus ; st, stapes ; ^y, pyramid from which the tendon of the stapedius muscle is seen emerging ; 11, tendon of the tensor tympani cut short near its insertion ; , anterior ligament of the malleus: the processus gracilis is concealed by the lower fibres of this ligament; , superior ligament of the malleus ; /. i, liga- ment of the incus ; ch, chorda tympani nerve passing across the outer wall of the tympanum. fenestra oval
. Elementary physiology . Fig. 116.—View of the left membrana tympani and auditory ossicles from the inner side, and somewhat from above (E. A. S ). f 7n, malleus ; i, incus ; st, stapes ; ^y, pyramid from which the tendon of the stapedius muscle is seen emerging ; 11, tendon of the tensor tympani cut short near its insertion ; , anterior ligament of the malleus: the processus gracilis is concealed by the lower fibres of this ligament; , superior ligament of the malleus ; /. i, liga- ment of the incus ; ch, chorda tympani nerve passing across the outer wall of the tympanum. fenestra ovalis. The fenestra ovalis, as well as another opening on the internal wall of the tympanum, also covered by membrane and called the fenestra rotundis, communicates with the internal ear. The purpose of these two communications will be pointed out later. The cavity of the middle ear is filled with air, and is in communication with the atmospheric air by means of a passage or tube called the Eustachian tube, which opens into the pharynx (see 4, Fig. 115). The purpose of the Eustachian tube is to keep the air at equal pressure on both sides of the tympanic membrane, so that this may be free to vibrate, and not be forced in or out by difference in air-pressure on its two surfaces. The tube S
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Keywords: ., bookcentury1800, bookdecade1890, bookpubli, booksubjectphysiology
