. Nursing in diseases of the eye, ear, nose, and throat . nd then downwardin the posterior wall runs the facial nerve, lying in itsbony canal the aquaeductus Fallopii. The anterior wall has in it near the bottom an open-ing for the Eustachian tube, which runs from the middleear to the throat. Its trumpet-shaped opening into thethroat dilates during the act of swallowing and admitsair to the middle ear, thus keeping the pressure equalon both sides of the drum membrane. Into the mouthof this tube the catheter is placed when direct inflationof the middle ear is practised. The posterior wall of th
. Nursing in diseases of the eye, ear, nose, and throat . nd then downwardin the posterior wall runs the facial nerve, lying in itsbony canal the aquaeductus Fallopii. The anterior wall has in it near the bottom an open-ing for the Eustachian tube, which runs from the middleear to the throat. Its trumpet-shaped opening into thethroat dilates during the act of swallowing and admitsair to the middle ear, thus keeping the pressure equalon both sides of the drum membrane. Into the mouthof this tube the catheter is placed when direct inflationof the middle ear is practised. The posterior wall of the tympanum has near its topan opening into the mastoid antrum called the aditus. 180 EYE, EAR, NOSE, AND THROAT NURSING Through this opening inflammation may extend fromthe middle ear to the mastoid cells, causing mastoiditis. The superior wall is a thin plate of bone separatingthe middle ear from the brain. The inferior wall iscalled the floor. The tympanum is lined with mucousmembrane, which is continuous with that lining theaditus and mastoid Fig. 37. —The drum-membrane and ossicles from within, showing at-tachment of malleus handle to drum-head (Pyles Personal Hygiene). The upper part of the tympanum behind ShrapneWsmembrane, level with the aditus, is called the attic. Thisregion contains the bones of the middle ear (Fig. 37). The ossicles, or bones of the middle ear, are three innumber and are called respectively the malleus, incus,and stapes or hammer, anvil, and stirrup. The malleus,the most external bone, has its handle woven into themiddle of the tympanic membrane. When sound- OUTLINE OF ANATOMY AND PHYSIOLOGY OF EAR 181 waves strike the ear drum the motion is imparted tothe malleus, and by an interlocking- union is transmittedto the incus, thence to the stapes, and by its foot-plate,which is woven into the membrane closing the ovalwindow, to the fluid of the internal ear. The musclesof the ossicles are two—the tensor tympani and the Body of incusHandle of
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Keywords: ., bookcentury1900, bookdecade1920, booksubjectotorhin, bookyear1922
