ioo The Ear 



The lining membrane of the tube contains mucous glands an 

 covered by columnar ciliated epithelium, except at the pharyngeal 

 opening, where it is squamous. The osseous part of the tube receives 

 its arterial supply from the vessels of the tympanum, and the carti- 

 laginous part from those of the pharynx. The lymphatics end in 

 glands about the angle of the jaw. 



In the case of inflammation of the pharynx, the tube and the tym- 

 panum may be secondarily implicated, and when an acute inflammation 

 has travelled back, abscess may be set up in the middle ear. Thus 

 may be explained the destruction of the membrana tympani and the 

 permanent deafness which sometimes follow scarlet fever, or which, in 

 an unhealthy child, may result from acute tonsillitis. 



On account of the tonsil being below the soft palate (p. in), and 

 the soft palate close below the opening of the tube, enlargement of the 

 tonsil may, indirectly, cause obstruction of the tube and deafness, but 

 more often the blockage is due to hypertrophy of the neighbouring 

 adenoid tissue, which is affected at the same time as the tonsil. 



Obstruction oftbe Eustachian tube is usually caused by inflam- 

 mation. Air being then unable to enter the tympanum, the pressure 

 on the exterior of the membrane is in excess of that within. The result 

 is that the membrane and the malleus are thrust inwards, and, the incus 

 being forced against the stapes, there is a constant pressure against 

 the fluid of the vestibule ; this causes irritation of the terminal filaments 

 of the auditory nerve, which is recognised as a meaningless but annoy- 

 ing buzz or singing. , 



If the blocking of the tube be but slight, the singing may cease 

 after the act of swallowing, as these movements pull down the lower 

 end of the expanded opening of the Eustachian tube (p. 108) and allow 

 air to pass along. If this fail, success may follow on the person holding 

 the nose and blowing it hard, which effort may force the compressed air 

 beyond the obstruction, thrusting out the membrana tympani, and 

 drawing upon the plate of the stapes at the oval foramen. If this also 

 fail, the surgeon may pump air up the nostrils by Politzer's apparatus 

 at the instant that the patient swallows a mouthful of water, so that the 

 compressed air may be locked above and behind the soft palate and the 

 palato-pharyngei, and, instead of being dissipated down the oesophagus, 

 may find its way into the middle ear. 



As a last resource the Eustachian catheter must be used. This 

 instrument, which is like a short and small silver catheter, is passed 

 lightly along the floor of the nose, with the point downwards, until it 

 touches the back of the pharynx. (It must not be allowed to enter the 

 middle meatus.) It is then withdrawn a little, the point being turned 

 outwards, and it should be felt to hitch against, and jump over, the 

 posterior edge of the cartilaginous expansion of the tube ; it is then 

 gently pushed upwards and outwards into the tube, after which it should 

 be felt to be in the firm fcrasp of the tabe, otherwise tho beak has not 





