94 THE EAE. 



their descriptions have not been confirmed by later research. Of the two muscles 

 generally recognised, one is attached to the malleus, and the other to the stapes. 



The tensor tympani is the larger of these muscles. It consists of a tapering 

 fleshy part, about half an inch in length, and a slender tendon. The muscular 

 fibres arise from the cartilaginous end of the Eustachian tube and the adjoining 

 surface of the sphenoid bone, and from the sides of the canal in which the muscle 

 lies and in which it is conducted backwards to the cavity of the tympanum. 

 Immediately in front of the fenestra ovalis the tendon of the muscle bends at nearly 

 a right angle over the end of the processus cochleariformis as round a pulley, and, 

 contained in a fibrous sheath, passes outwards, to be inserted into the inner part of 



Fig. 102. PROFILE VIEW OP THE LEFT MEMBRANA TYMPANI AND AUDITORY OSSICLES FROM BEFORE 

 AND SOMEWHAT FROM ABOVE. Magnified four times. (E. A. S. ) 



The anterior half of the membrane has been cut away by an oblique slice, m, head of the malleus ; 

 sp, spur-like projection of the lower border of its articular sin-face ; pr. br, its short process ; pr. gr, root of 

 processus gracilis, cut; s.l.m, suspensory ligamentof the malleus ; l.e.m, its external ligament; t.t, tendon of 

 the tensor tympani, cut ; i, incus, its long process ; st, stapes in fenestra ovalis ; e.au.m, external auditory 

 rneatus ; p.R, notch of Kivinus ; m.t, membrana tympani ; u, its most depressed pointer umbo ; d, de- 

 clivity at the extremity of the external meatus : i.au.m, internal auditory meatus ; a and b, its upper 

 and lower divisions for the corresponding parts of the auditory nerve ; n.p, canal for the nerve to the 

 ampulla of the posterior semicircular canal ; s.s.c, ampullary end of the superior canal ; p, ampullary 

 opening of the posterior canal ; c. common aperture of the superior and posterior canals ; e.s.c, ampul- 

 lary, and e'.s.c, non-ampullary end of the external canal ; s.t.c, scala tympani cochleae; /.?, fenestra 

 rotunda, closed by its membrane ; a. F y aqueduct of Fallopius. 



the handle of the malleus, close to its root (figs. 101, 102, tt). The tensor tympani 

 is supplied by a branch of the fifth pair through the otic ganglion. Its nerve is 

 furnished with a small ganglion (Dastre and Morat). 



The stapedins is a very distinct muscle, but is hidden within the bone, being 

 lodged in a canal in front of the descending part of the aqueductus Fallopii and in 

 the hollow of the pyramid. The tendon issues from the aperture at the apex of that 

 little elevation (fig. DO), and passing forwards, surrounded by a fibrous sheath, is 

 inserted into the neck of the stapes posteriorly, close to the articulation of that bone 

 with the lenticular process of the incus (figs. 90, 101). 



A very slender spine of bone has been found occasionally in the tendon of the 

 stapedius in man ; and a similar piece of bone, though of a rounder shape, exists 

 constantly in the horse, the ox, and other animals. 



