462 MUSCLES OF THE BONES OF THE EAR. 



When these bones are viewed in their natural position, the 

 short leg of the incus projects horizontally backwards, the 

 long process of the malleus horizontally forwards; the han- 

 dle of the malleus, and the long leg of the incus, directly down- 

 wards, one connected with the membrana tympani, and the 

 other with the foramen ovale, by the intervention of the orbi- 

 culare and stapes.* 



The Muscles of the Bones of the Ear. 



The aforesaid bones appear to be regularly articulated for 

 motion with each other, and they are furnished with several 

 muscles. 



One of these muscles runs in the bony canal above the Eus- 

 tachian tube, and is inserted into the posterior side of the 

 handle of the malleus, below the root of the long process. Its 

 effect is to draw in the malleus, and membrana tympani. It 

 is therefore called Tensor Tympani, or Internus Auris. 



Another muscle, as it is supposed to be, runs in the fissure 

 on the outside of the Eustachian tube, and is inserted into the 

 long process of the malleus. 



This is supposed to draw the malleus obliquely forward, and 

 of course to relax the tympanum. It is therefore called Lax- 

 ator Tympani, or Externus Mallei; but there are the strong- 

 est doubts respecting the muscularity of this organ. 



Morgagni, Haller, Lieutaud, and Meckel, could not satisfy 

 themselves that it was muscular ; and Sabatier also doubts it ; 

 while Bell, Fyfe, Hume, Bichat and Gavard, appear to adopt 

 the opinion of its muscularity. 



Some anatomists describe a third muscle of the malleus as 



arising from the superior posterior margin of the meatus audi- 



* Lassus, in his excellent discourse on Anatomy, informs us that Fallopius 

 and Eustachius described nearly the whole interior of the ear. The most 

 ancient authors had remarked the thin transparent membrane which closes the 

 extremity of the meatus externus. Fallopius describes particularly the tympa- 

 num ; of the four bones within it, the malleus, incus, os orbiculare, and stapes, 

 Berenger de Carpi described the two first ; Ingrasias, Eustachius, Columbus, and 

 Louis Collada, a Spanish physician, disputed the discovery of the fourth with 

 each other ; and Vesling assures us that Francis de la Boe, a Dutch physi- 

 cian, discovered the third, which is the smallest. — h. 



iiiii 



