THE BOXES OF THE EAR. 675 



cutaneous lining of the auditory canal, its inner surface 

 with, part of the ciliated mucous membrane of the tym- 

 panum. 



The small bones or ossicles of the ear are three, named 

 malleus, incus, and stapes. The malleus, or hammer-bone, is 

 attached by a long slightly-curved process, called its 

 handle, to the membrana tympani ; the line of attach- 

 ment being vertical, including the whole length of the 

 handle, and extending from the upper border to the centre 

 of the membrane. The head of the malleus is irregularly 

 rounded ; its neck, or the line of boundary between it and 

 the handle, supports two processes ; a short conical one, 

 which receives the insertion of the tensor tympani, and a 

 slender one, processus gracilis, which extends forwards, and 

 to which the laxator tympani muscle is attached. The incus, 

 or anvil-bone, shaped like a bicuspid molar tooth, is 

 articulated by its broader part, corresponding with the 

 surface of the crown of a tooth, to the malleus. Of its 

 two fang-like processes, one, directed backwards, has a 

 free end, the other, curved downwards and more pointed, 

 articulates by means of a roundish tubercle, formerly 

 called os orliculare, with the stapes, a little bone shaped 

 exactly like a stirrup, of which the base or bar fits into 

 the fenestra ovalis. To the neck of the stapes, a short 

 process, corresponding with the loop of the stirrup, is 

 attached the stapedius muscle. 



The bones of the ear are covered with mucous mem- 

 brane reflected over them from the wall of the tympanum ; 

 and are moveable both altogether and one upon the other. 

 The malleus moves and vibrates with every movement and 

 vibration of the membrana tympani, and its movements 

 are communicated through the incus to the stapes, and 

 through it to the membrane closing the fenestra ovalis. 

 The malleus, also, is moveable in its articulation with the 

 incus; and the membrana tympani moving with it is 

 altered in its degree of tension by the laxator and tensor 



