Fenestri vestibuli is:
(A) Rounded bulge produced by first turn of cochlea (B) Oval opening posterosuperior to the promontory (C) Prominence produced due to the lateral semicircular canal (D) It is grooved by tympanic plexus
(B) The Medial or Labyrinthine Wall
The medial wall separates the middle ear from the internal ear. It presents the following features.
(a) The promontory is a rounded bulging produced by the first turn of the cochlea. It is grooved by the tympanic plexus.
(b) The fenestra vestibule is an oval opening posterosuperior to the promontory. It leads into the vestibule of the internal ear and is closed by the foot-plate of the stapes.
(c) The prominence of the facial canal runs backwards just above the fenestra vestibule, to reach the lower margin of the aditus. The canal then descends behind the posterior wall to end at the stylomastoid foramen.
(d) Above the prominence of facial canal lies the prominence produced due to the lateral semicircular canal.