ATTACHMENT OF THE STAPES TO THE FENESTRA OVALIS. 123 



that they have escaped into the semicircular canals from the 

 utriculus. 



6. THE FENESTRA OVALIS, AND ITS CONNECTION WITH THE 

 BASE OF THE STAPES. 



The majority of authors describe the insertion of the base 

 of the stapes into the fenestra ovalis as being of a very 

 simple nature, whilst I, on the contrary, find that it is rather 

 complicated. That Soemmering* had already noticed this, is 

 evident from his remark, "that the basis of the stapes is 

 attached to the fenestra ovalis by a delicate articular capsule." 

 But it is impossible to determine from this brief expression 

 whether Soemmering meant to indicate by the term articular 

 capsule the existence of a proper joint, or only the presence 

 of a fibrous layer resembling a fibrous articular capsule. 

 Several writers speak of a simple fibrous union, to which they 

 apply the term Ligamentum orbiculare baseos stapedis. It was 

 reserved for the active Englishman, Toy nbee, to furnish an exact 

 description of the mode of connection of the base of the stapes 

 with the fenestra ovalis. 



The difference in form between the anterior and the poste- 

 rior border of the base of the stapes, which in a physiological 

 point of view is certainly of importance, was first noticed by 

 Toy nbee, f by whom also the hyaline cartilage between the 

 fenestra ovalis and the base of the stapes was first described. 



If in a successful horizontal section the anterior extremity 

 of the base of the stapes be compared with the posterior, it is ob- 

 servable that besides the thickening which exists at these spots, 

 the moderately broad posterior surface of contact forms almost a 

 right angle with the vestibular surface of the base of the stapes, 

 and that the base towards the posterior limb of the stapes runs 

 off into a kind of process (fig. 317). The surface of contact at the 

 anterior margin of the base is somewhat narrower than at the 

 posterior, and forms an acute angle with its vestibular surface, 

 so that the whole anterior extremity which projects beyond 

 the corresponding limb appears somewhat longer than the 



* VomBau des menschlichen Korpers. Frankfort, 1796. Theil ii., p. 12. 

 t British and Foreign Medico-C'hiruryical Hevieu; 1853. 



