614 THE EAE 



In the upper quadrant of the tympanic membrane, above the 

 attachment of the malleus, the fibrous layers are wanting ; the 

 mucous and cutaneous layers are therefore in contact, and the mem- 

 brane presents a flaccid appearance in comparison with the tense 

 condition of its other parts. This portion is known as Shrapnell's 

 membrane. 



The Auditory Ossicles. These are three in number, the mal- 

 leus, the incus, and the stapes ; they form a continuous bony 

 chain, extending from the insertion of the manubrium mallei in 

 the tympanic membrane to the fenestra ovalis, with whose margin 

 the foot of the stapes articulates. The ossicles consist of compact 

 bony tissue containing loosely packed Haversian systems ; they are 

 united with each other by firm fibro-cartilaginous articulations. 

 With the exception of the stapes, none of the ossicles contain a 

 marrow cavity. 



The manubrium of the malleus is firmly fixed in the tympanic 

 membrane, as already described, the head of the bone articulating 



FIG. 447. THE AUDITORY OSSICLES. 



I, ossicular chain of the left ear ; 1, malleus ; #, incus ; #, stapes. JJ, ossicular chain 

 of the right ear ; 1, malleus ; #, processus gracilis ; 3, manubrium ; h long process of the 

 incus ; 5, short process of the incus ; 6, stapes. (After Kiidinger.) 



with the head of the incus in the epitympanic recess. The long 

 process of the incus, circular in transection, extends downward 

 along the tympanic wall in a course nearly parallel to that of the 

 manubrium mallei, being, in a portion of its course, contained 

 within a recess in the osseous wall of the tympanum. Finally, at 

 the level of the stapes it makes a sharp bend, almost at right angles 



