ON THE DEVELOPMENT OF THE MEMBRANA TECTO- 



RIA WITH REFERENCE TO ITS STRUCTURE 



AND ATTACHMENTS 



C. W. PRENTISS 

 The Anatomical Laboratory of the Northwestern University Medical School, Chicago 



FOtJETEEN FIGURES 



For more than half a century various investigators have studied 

 the structure of the cochlea with conflicting results. Compara- 

 tively recently Kishi ('07) and Shambaugh ('07) have championed 

 the view originally held by Retzius ('84), that the membrana 

 tectoria remains attached to the organ of Corti. They maintain 

 moreover that the membrana is the^ logical structure through 

 which sounds are transmitted to the auditory cells, and that it 

 acts as a resonator. This function Von Helmholtz was the first 

 to ascribe to the rods of Corti and later with Hensen to the 

 fibers of the basilar membrane. 



Hardesty ('08) denies the existence of an attachment between 

 the membrana and the spiral organ, yet maintains that through 

 the medium of the membrane sound vibrations are transmitted 

 to the auditory hairs. A voluminous literature has been written 

 deahng with the physiology of an organ the structure of which 

 is inadequately known. To ascribe a definite function to the 

 membrana tectoria we must first know with absolute certainty 

 its structure and attachments. No physicist will accept as an 

 important organ of hearing a membrane of indefinite structure 

 and with no fixed position with reference to the spiral organ 

 itself. For such a floating membrane, as we shall show later 

 on, may readily change its position and relations to the auditory 

 cells, and would certainly interfere with and interrupt the audi- 

 tory function. 



425 



