62 THE EXTERNAL AND MIDDLE EAR, BY J. KESSEL. 



lined. The tensor tympani is connected with the dilatator 

 tubse, not only by tendinous fasciculi, as Majer (27) asserts, but 

 also by muscular fibres, as I have already had an opportunity 

 of stating. At the point of its attachment to the malleus, 

 cartilage cells may frequently be found imbedded in its 

 tendon. 



THE CELLS OF THE MASTOID PROCESS. 



The mastoid cells are lined by a very thin mucous mem- 

 brane, which is continued into them from the tympanic cavity, 

 and, speaking generally, preserves the same anatomical 

 characters in both regions. The epithelium is composed of 

 smooth cells presenting the features that have already been 

 described as characterising those of the membrana tympani. 

 Beneath them is a layer of connective tissue, and beneath this 

 again a second layer of connective tissue representing the 

 periosteum, and containing numerous nerves, bloodvessels, and 

 lymphatics. The upper layer of connective tissue frequently 

 projects in the form of membranes at the free borders of the 

 cells, which extend to adjoining bony processes where they 

 are inserted, and owing to which not unfrequently the cavities 

 of two adjoining cells are shut off from each other. In the 

 larger cell cavities these membranes are stretched horizontally, 

 so as to form a kind of tent, by means of trabeculse proceeding 

 from them. In the trabeculse of the membranes the peculiar 

 organs with concentric striation, formerly described, occur with 

 great frequency (I have counted as many as seven). They 

 never attain here to the same size as those of the tympanic 

 cavity, but nevertheless present a much greater variety of 

 interesting forms. They vary from the small fusiform variety 

 to the large spheroidal, clavate, and finger-biscuit form. I have 

 repeatedly noticed membranes with their processes and the 

 corpuscles adherent to them in the aditus ad cellulas, and 

 have also seen trabeculee in direct connection with the pro- 

 cessus brevis of the incus. 



