Subject: Re: Oval and round windows From: Erik Larsen <elarsen@xxxxxxxx> Date: Tue, 3 Oct 2006 11:12:14 -0400Perhaps the oval shape is simply a means to reduce the mass of the stapes footplate (and the associated mass loading of the perilymph in the vestibule). Keeping the mass small would allow better high-frequency hearing. I'm not sure if reducing a round to an oval shape makes a substantial mass difference (considering the other masses in the ossicular chain), but this is my best immediate guess at a simple reason for the oval shape. The round window's main function is for pressure relief, so you want the membrane to be as compliant as possible (for good low-frequency hearing), which I'm pretty sure is achieved with a round shape. Again, this is just a guess at a simple explanation. Erik -- Erik Larsen Eaton-Peabody Laboratory of Auditory Physiology Massachusettts Eye & Ear Infirmary 243 Charles St Boston MA 02114 https://research.meei.harvard.edu/epl/index.html Lawrence Borden wrote: > Hello Folks, > > Although it is probably a simple question for most of you, I have not run > across an answer to a question that occurred to me while gazing at the > lovely structure of the middle ear. Can anyone offer an explanation as to > why one window is oval while the other is round? Is there some additional > mechanical advantage to differing shapes? > > Lawrence Borden > Vanderbilt University > Lawrence.Borden@xxxxxxxx >