CHAP, iv.] HEARING. 1325 



skin consisting of dermis and a rather thin epidermis, in which the 

 distinction between the malpighian and corneous layers is not- 



FIG. 170. THE OSSICLES IN POSITION. Magnified four times. (After Hensen.) 



The figure represents a section through tympanum in the line of the long axis of the 

 malleus and incus ; the short process of the incus p'b' has been cut through. 



T. C. The tympanic cavity, mbr. handle of malleus, u. umbo. p.b. short process 

 of the malleus shewn in dotted outline as pushing outwards the membrana 

 flaccida. T.T. the attachment of the tendon of the tensor tympani. Ig. the 

 attachment of the external ligament of the malleus. Ig.s. the superior ligament 

 of the malleus, t.t. the teeth of the incus, p'l'. the long process, shaft, of the 

 incus. St. the stapes. 



very sharp. Blood vessels and a nerve (nervus membranae tym- 

 pani, a branch of the auricnlo-temporal) run in the dermis. The 

 mucous membrane, lining the inner surface of the membrane, 

 consists of a single layer of flattened non-ciliated epithelium cells 

 lying on a dermis in which is much reticular connective tissue. 

 It will be understood that this mucuous membrane is continued 

 over the handle of the malleus, as indeed over the rest of the 

 ossicles. 



814. The handle of the malleus being thus firmly imbedded 

 in the substance of the tympanic membrane moves with every 

 movement of it ; the attachment of the short process to the 

 flaccid part of the membrane is of a looser character. Besides 

 this attachment to the tympanic membrane the malleus is further 

 bound to the wall of the tympanum by three ligaments of con- 

 nective tissue. One, the superior ligament (Figs. 167, 168, 170, 

 Ig.s.) descends from the upper wall of the tympanum to the head 

 of the malleus, whose movements it thus steadies. More important 

 however than this are the other two ligaments which pass more 

 or less horizontally from the outer wall of the tympanum above 

 the tympanic membrane, to the neck of the malleus. One placed 



