All of the following are true about the middle ear cavity except -
Ans. is 'c' i.e., the Medial wall is formed by tympanic membrane Boundaries of the Middle ear:Roof - Tegmental wall (tegmen tympani) separates the middle ear from the middle cranial fossaFloor - Jugular wall separates the middle ear from the superior bulb of the internal jugular vein.Anterior - Carotid wall inferior part separates the middle ear from the internal carotid arteryHas two openings - tensor tympani and auditory tube.Posterior - Mastoid wall opening superiorly(aditus) through which epitympanic process communicates with the mastoid antrum.Lateral or Membranous wall - tympanic membrane separates the middle ear from the external acoustic meatus.6. Medial - Labyrinthine wail separates the middle ear from the internal ear. It has promontory, fenestra vestibuli, fenestra cochleae, sinus tympani.Contents of the tympanic cavityo Contents of the middle ear (tympanic cavity) are:-Ear ossicles - Malleus, incus, stapesMuscles - Tensor tympani, stapediusChorda tympaniTympanic plexusOssicles of the middle earo The middle ear contains three ear ossicles (from lateral to medial) Malleus, incus, and stapes. The ossicles transmit sound vibrations from the large tympanic membrane into the small oval window, at a huge mechanical advantage. The malleus articulates with incus, which in turn articulates with the stapes. Types of the joint areThe incudomalleolar joint - Saddle type of synovial joints.The included-stapedial joint - Ball & socket type of synovial joints.o Stapes footplate is held in the oval window by annular ligament.o The nerve supply of middle ear is derived from tympanic plexus which lies over the promontory. The inferior ganglion of the glossopharyngeal nerve6 gives off the tympanic nerve which enters the middle ear through the tympanic canaliculus and takes part in the formation of the tympanic plexus on the medial wall of the middle ear. This distributes its fibers to the middle ear, and also to the auditory tube, mastoid antrum, and air cells.
Roof is formed by tegmen tympani
Anterior wall has opening of two canals
Medial wall is formed by tympanic membrane
Floor has bulb of internal jugular vein