THE CKANIUM. 



1367 



chin may fracture the tympanic plate as well as the base of the skull, that pain on 

 mastication is usually complained of in acute inflammatory affections of the meatus 

 and middle ear, and that in young children, in whom the tympanic plate is incom- 

 pletely ossified, suppurative inflammation is liable to extend from the ear to the 

 parotid region. 



Clinically, to obtain a view of the membrana tympani a speculum and a reflecting 

 )r are employed ; the auricle is pulled upwards, backwards, and laterally in order to 



Middle fossa of skull 

 Tensor tympani muscle 



Processus cochleariformis 

 Eminence of lateral 

 semicircular canal 



/ Tympanic antrum 



Auditory tube 



Retro-pharyngeal lymph gland 



Internal carotid artery 



Internal jugular vein 



-Tranverse sinus 

 Posterior fossa of skull 



\Rudimentary mastoid process 

 Facial nerve 

 Pyramid 



Section of jugular fossa 

 Stapes 



Promontory 

 FIG. 1072. VIEW OF THE LABYRINTHINE WALL OF THE MIDDLE EAR. 



tion through the left temporal bone of a child, to show the relations of the tympanum and tympanic antrum 

 to the middle and posterior fossae of the skull. 



straighten the cartilaginous part of the canal. The healthy membrane is pearly gray, semi- 

 opaque, slightly concave, and obliquely placed, being inclined laterally, especially above 

 and behind. 



The handle and lateral process of the malleus, both embedded in the membrana tympani, 

 : are the only objects distinctly seen when the healthy ear is examined with the speculum. 



Groove for posterior branch of middle meningeal artery 

 Aditus ad antrum 



\ 



Tympanic antrum 

 Transverse sinus- 



Incus 



Middle cranial fossa 



/ Tegmen tympani 



^ Epitym panic recess 



^-Chorda tympani nerve 

 I ^.Tensor tympani muscle 



- Handle of malleus 

 -Carotid canal 

 .Tympanic membrane 



_ Jugular fossa 



i__Styloid process 



Mastoid process 



Stylo-mastoid foramen 

 i. 1073. SECTION THROUGH LEFT TEMPORAL BONE, SHOWING TYMPANIC WALL OF TYMPANIC CAVITY, ETC. 



The lateral process of the malleus projects laterally, and presents itself, therefore, as a 

 distinct knob-like projection at the superior part of the membrane ; passing forwards and 

 1 backwards from this process are the anterior and posterior malleolar folds of the membrana; 

 they form the lower limit of the pars flaccida of the membrane, and correspond to the line 

 of the chorda tympani nerve. The handle of the malleus, situated at the junction of the 

 two upper quadrants, is seen passing downwards and backwards to the point of maximum 



