The round window serves as a pressure-release valve for incompressible cochlear fluid.

Evidence

The membrane covering the round window moves to compensate for oval window movements, since the perilymph fluid is essentially incompressible. Inward movements of the stapes footplate at the oval window cause the round window to move outward, and outward movements of the stapes footplate cause the round window to move inward. These movements cause traveling waves to be set up in the scala vestibuli, which displace both Reissner’s membrane and the basilar membrane. — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 546

Categorization

• DEFINE: Explains the mechanical function of the round window in the cochlea.
• XREF: Connects to the physics of incompressible fluids pressurized in closed chambers, relevant to any hydraulic analogies. — connects to: Incompressible cochlear fluid requires the round window to counter-move with the stapes — David M. Howard, Jamie Angus, Acoustics and Psychoacoustics, 546