What is the middle ear and what is its primary function?

The middle ear is an air-filled space in the temporal bone that contains the auditory ossicles. Its main functions are to transmit sound from the tympanic membrane to the inner ear and maintain ventilation via connections to the nasopharynx and mastoid antrum.

What are the three main subdivisions of the middle ear?

The middle ear is divided into three parts: Epitympanum (above the tympanic membrane, containing the head of malleus and body of incus), Mesotympanum (opposite the tympanic membrane, containing the handle of malleus, long process of incus, and stapes), and Hypotympanum (below the membrane, an air-filled recess).

Which nerves supply the middle ear?

The middle ear is supplied by CN IX via the tympanic plexus, CN VII via the chorda tympani and nerve to stapedius, CN V3 for the tensor tympani muscle, and sympathetic fibers from the carotid plexus.

What are the auditory ossicles and what do they do?

The auditory ossicles are three small bones: malleus, incus, and stapes. They form a chain that transmits sound vibrations from the tympanic membrane to the oval window of the inner ear, amplifying the signal for hearing.

What is the role of the pharyngotympanic tube?

The pharyngotympanic tube (also called the auditory tube) connects the middle ear to the nasopharynx. It helps maintain pressure equilibrium across the tympanic membrane, ensuring proper sound transmission and ventilation.

What structures form the boundaries of the middle ear?

The middle ear is bounded by the roof (tegmen tympani), floor (thin plate over jugular bulb), anterior wall (related to internal carotid artery), posterior wall (with aditus ad antrum), medial wall (with promontory and windows), and lateral wall (tympanic membrane).

How does the middle ear develop embryologically?

Embryologically, the middle ear and auditory tube develop from the tubotympanic recess of the first pharyngeal pouch. The ossicles form from pharyngeal arch cartilages: malleus and incus from the first arch, and stapes from the second arch.

Middle Ear – Ossicles, Muscles & Boundaries

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