Corpus: Oval window

The term fenestra ovalis or oval window refers to the roughly oval opening in the wall of the tympanic cavity facing the labyrinth.

The oval window lies superior to the round window (fenestra cochleae) and marks the beginning of the so-called vestibular staircase (scala vestibuli) of the cochlea. It connects the tympanic cavity with the labyrinth vestibule (Vestibulum labyrinthi), but is closed by the foot plate of the stapes and the anular stapedial ligament (Ligamentum ovale).

The vibrations of the footplate in the fenestra ovalis transmit the sound waves hitting the eardrum into the inner ear, where they are amplified almost 30 times.

A leak in the ligamentum ovale can lead to a leakage of perilymph into the tympanic cavity. Depending on its size, this leakage is referred to as an oozing or gusher.