THE EAR 199 



portion into line with the lateral part of the osseous portion, 

 and this can be effected by dragging the auricle upwards and 

 forwards. 



In the young child the osseous portion of the meatus is 

 very short and the downward direction of the lateral surface 

 of the membrane is more marked than it is in the adult. 



The narrowest part of the meatus is placed at about one- 

 third of an inch from the membrane, and foreign bodies which 

 succeed in passing beyond this point may only be removed 

 with difficulty. The whole of the meatus is covered by a 

 cuticular lining, which is firmly adherent both to the cartil- 

 aginous and to the osseous walls, and, on this account, 

 furuncles in the meatus are a source of very acute pain. 



The cerumen, or ear-wax, is secreted by the modified sweat 

 glands of the cuticular lining and it is normally worked to 

 the exterior by the movements of the mandibular condyle, 

 which lies below and in front of the cartilaginous meatus. 

 If the finger is placed in the external acoustic meatus and 

 the mouth is alternately opened and closed, the effect of the 

 movements of the condyle on the lumen of the meatus can 

 be readily demonstrated. 



The cuticular lining of the meatus, which also covers the 

 lateral aspect of the tympanic membrane, is supplied, almost 

 entirely, by branches from the auricula-temporal nerve. The 

 postero-inferior part of the membrane and the adjoining parts 

 of the meatus, however, receive additional supply from the 

 auricular branch of the vagus (p. 96). Referred pain in the 

 external acoustic meatus may be due to irritation of any of 

 the terminal branches of the trigeminal nerve, but it is most 

 commonly associated with inflammatory conditions of the 

 teeth of the mandible and consequent stimulation of the 

 inferior alveolar (dental) nerve (p. 75). Similar pain may 

 occur as the result of stimulation of terminal branches of 

 the vagus, but this condition is by no means common. 

 Further, not only may the meatus be the site of referred pain, 

 but pathological conditions in the meatus may give rise to 



