PRACTICAL CONSIDERATIONS: THE EXTERNAL EAR. 1491 



The skin is closely adherent to the underlying tissues, especially on the anterior 

 surface, so that the exudate is under much tension, interfering with the blood- 

 supply. The nerves are also compressed, accounting- for the great pain. 



Hcematomata of the auricle are due to effusions of blood between the cartilage 

 and its perichondrium. They occur usually on the concavity of the auricle from a 

 blow, as in boxers, or foot-ball players. They may occur rarely, without traumatism, 

 as in the insane, although some believe that injury is the exciting cause in these 

 cases ; or even, in very exceptional instances, may appear without precedent trauma 

 or mental disease. In those cases in which there iS great tension, it may be neces- 

 sary to incise and drain to prevent necrosis. 



Of the tumors, keloid, following punctures for ear-rings, is common in the 

 negro ; capillary naevi are frequent, whilst cirsoid aneurism may occur. Cysts in 

 connection with the first branchial cleft have already been mentioned. 



The External Auditory Canal. — Congenital atresia is rare and is often 

 associated with malformations of the auricle, the middle and the internal ear, so 

 that correction of the external condition will usually fail to restore the hearing. 



The length of the external meatus is about 1% inches, about ^ inch of which 

 is bony and about % inch cartilaginous. In the new-born it consists of skin and 

 cartilage only, and its lumen is very small. Owing to the obliquity of the tympanic 

 membrane, that structure, in the new-born, is in close contact with the floor of the 

 canal, so that the latter must be drawn away from the membrane to expose it. For 

 this purpose the auricle should be drawn downward and backward. The skin of 

 the cartilaginous portion is supplied with hair, sebaceous and ceruminous glands. 

 Furuncles are frequent, the infection passing along the hair-follicles to the asso- 

 ciated sebaceous glands. In some persons, one boil follows another from successive 

 glandular infection. The skin of the bony portion is thinner than that of the car- 

 tilaginous, except in the posterior part of the roof, where a thicker wedge-shaped 

 piece containing glands extends as far as the drum-head. 



Ceruminous masses often collect, and frequently contain pathogenic bacteria. 

 They may press upon the tympanic membrane, and through intralabyrinthine pres- 

 sure may produce vertigo, or may lead to vomiting or convulsions. Interference 

 by the mass with air conduction may result in loss of hearing. 



A diffuse infection of the meatus may be primary, but it is more apt to be a 

 secondary result of otitis media. In severe cases the pus may extend to the bone 

 separating the periosteum. It may then pass to the parotid region through the 

 anterior bony wall, but it is more likely to do so through the fissures in the cartilag- 

 inous portion. Abscesses in the parotid region more frequently extend by the same 

 route in the reverse direction. 



The general direction of the canal is from without inward, downward, and 

 slightly forward. The auricle and cartilaginous meatus are suspended from the 

 margin of the bony portion so that an angle is formed opening downward. For 

 a short distance from the external orifice the meatus inclines forward. In the remain- 

 ing cartilaginous portion it turns backward, while in the bony portion it. is again 

 deflected forward. Therefore, to examine the tympanic membrane the cartilaginous 

 meatus must be drawn upward to correct the vertical curve, and backward to 

 straighten the antero-posterior curve. 



The diameter of the canal is greater at the two extremities than in the centre. 

 The smallest diameter in the bony portion is at the inner third, where foreign bodies 

 most frequently lodge, which have been known to remain in the canal for years 

 without much discomfiture, or even, in some cases, without their presence being 

 known. Care is necessary in their removal lest the tympanic membrane be injured. 



The anterior wall of the meatus is in relation with the temporo-maxillary articu- 

 lation, and its bony portion has been fractured from blows upon the lower jaw. The 

 parotid gland is in relation with this wall as well as with the floor, so that tumors of 

 the gland may narrow or occlude the canal by pressure. Parotid abscesses opening 

 into the canal are likely to pass through the deficiencies in the cartilage (fissures of 

 Santorini). Since the lower jaw is in relation with the cartilaginous as well as with 

 the bony portion of the meatus, the former is drawn forward when the mouth is. 

 opened. Hence the mouth is usually opened when one listens intently. 



