Table of Contents
Middle Ear Structures
The middle ear, also known as the tympanic cavity, is a tiny, irregular chamber that is laterally compressed and located inside the temporal bone. It is also called the tympanum. The tympanic membrane separates it from the external auditory meatus.
The middle ear consists of:
- Auditory ossicles
- Eustachian tube
- Auditory muscles
Middle Ear Anatomy – Diagram
The middle ear contains the ear ossicles, auditory muscles, nerves and eustachian or auditory tube. The inner ear’s cochlear fluid receives vibrations from the eardrum through these ear ossicles. The tympanic cavity is a hollow area in the middle ear that is inflated with air.
Auditory Ossicles
The middle ear’s auditory ossicles are a chain-like arrangement of three tiny bones that extend from the tympanic membrane to the oval window. The three auditory ossicles are:
- Malleus or hammer – It has a head, a neck, and a hand. The manubrium or hand is joined to the tympanic membrane. The neck stretches from the hand to the head. The capitulum or head articulates with the body of the incus.
- Incus or anvil – One long and one short process make up the incus’ body. The body’s front surface articulates with the malleus head. A ligament is attached to the short process. The lengthy process runs parallel to the hand of the malleus. The lenticular process, or knob-like tip of the long process, articulates with the stapes.
- Stapes or stirrup – It is the body’s tiniest bone. It has a head, neck, footplate, anterior and posterior crus. Incus articulates the head. The footplate slides into the oval window.
Explore: MCQs on Structure of Ear
Eustachian Tube
The flattened canal that runs from the middle ear’s anterior wall to the nasopharynx is called the eustachian tube. It is also known as the auditory tube. The bony wall surrounds its upper portion, while the fibrocartilaginous plate surrounds its lower portion. The eustachian tube, which connects the middle ear with the back of the nose, creates the airway between the middle ear and the atmosphere. As a result, the pressure across the tympanic membrane is balanced.
Auditory Muscles
Two skeletal muscles are attached to auditory ossicles. They are:
- Tensor tympani – The larger of the two muscles in the tympanic cavity is the tensor tympani. It arises from the eustachian tube’s cartilaginous section. Through the malleus, the tensor tympani is connected to the tympanic membrane. The tympanic membrane is constantly pulled or strained by these muscles for sound waves to be transmitted.
- Stapedius – The smallest skeletal muscle in the human body is the stapedius. It is located in a conical bony chamber on the posterior wall of the tympanic cavity. It stops the stapes from moving too much. When it contracts, the footplate moves less against the cochlear fluid and drags the stapes’ neck backwards.
This was a brief note on the anatomy of the middle ear. For more NEET related content, visit BYJU’S.
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