The inner ear is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts:
The middle ear is the portion of the ear medial to the eardrum, and distal to the oval window of the cochlea.
The ossicles are three bones in either middle ear that are among the smallest bones in the human body. They serve to transmit sounds from the air to the fluid-filled labyrinth (cochlea). The absence of the auditory ossicles would constitute a moderate-to-severe hearing loss. The term "ossicle" literally means "tiny bone". Though the term may refer to any small bone throughout the body, it typically refers to the malleus, incus, and stapes of the middle ear.
The incus or anvil is a bone in the middle ear. The anvil-shaped small bone is one of three ossicles in the middle ear. The incus receives vibrations from the malleus, to which it is connected laterally, and transmits these to the stapes medially. The incus is so-called because of its resemblance to an anvil.
The stapes or stirrup is a bone in the middle ear of humans and other animals which is involved in the conduction of sound vibrations to the inner ear. This bone is connected to the oval window by its annular ligament, which allows the footplate to transmit sound energy through the oval window into the inner ear. The stapes is the smallest and lightest bone in the human body, and is so-called because of its resemblance to a stirrup.
The oval window is a membrane-covered opening from the middle ear to the cochlea of the inner ear.
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the organ of Corti, the sensory organ of hearing, which is distributed along the partition separating the fluid chambers in the coiled tapered tube of the cochlea.
The angular is a large bone in the lower jaw (mandible) of amphibians and reptiles, which is connected to all other lower jaw bones: the dentary, the splenial, the suprangular, and the articular. It is homologous to the tympanic bone in mammals, due to the incorporation of several jaw bones into the mammalian middle ear early in mammal evolution.
An ear is the organ that enables hearing and body balance using the vestibular system. In mammals the ear is usually described as having three parts: the outer ear, the middle ear and the inner ear. The outer ear consists of the pinna and the ear canal. Since the outer ear is the only visible portion of the ear in most animals, the word "ear" often refers to the external part alone. The middle ear includes the tympanic cavity and the three ossicles. The inner ear sits in the bony labyrinth, and contains structures which are key to several senses: the semicircular canals, which enable balance and eye tracking when moving; the utricle and saccule, which enable balance when stationary; and the cochlea, which enables hearing. The ear is a self cleaning organ through its relationship with earwax and the ear canals. The ears of vertebrates are placed somewhat symmetrically on either side of the head, an arrangement that aids sound localization.
Tympanoplasty is the surgical operation performed to reconstruct hearing mechanism of middle ear.
The stapedius is the smallest skeletal muscle in the human body. At just over one millimeter in length, its purpose is to stabilize the smallest bone in the body, the stapes or stirrup bone of the middle ear.
The tensor tympani is a muscle within the middle ear, located in the bony canal above the bony part of the auditory tube, and connects to the malleus bone. Its role is to dampen loud sounds, such as those produced from chewing, shouting, or thunder. Because its reaction time is not fast enough, the muscle cannot protect against hearing damage caused by sudden loud sounds, like explosions or gunshots.
The tympanic cavity is a small cavity surrounding the bones of the middle ear. Within it sit the ossicles, three small bones that transmit vibrations used in the detection of sound.
The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane, which vibrates with opposite phase to vibrations entering the inner ear through the oval window. It allows fluid in the cochlea to move, which in turn ensures that hair cells of the basilar membrane will be stimulated and that audition will occur.
The tympanum is an external hearing structure in animals such as mammals, birds, some reptiles, some amphibians and some insects.
The evolution of mammalian auditory ossicles was an evolutionary process that resulted in the formation of the bones of the mammalian middle ear. These bones, or ossicles, are a defining characteristic of all mammals. The event is well-documented and important as a demonstration of transitional forms and exaptation, the re-purposing of existing structures during evolution.
Hearing, or auditory perception, is the ability to perceive sounds through an organ, such as an ear, by detecting vibrations as periodic changes in the pressure of a surrounding medium. The academic field concerned with hearing is auditory science.
Cochlea is Latin for “snail, shell or screw” and originates from the Greek word κοχλίας kokhlias. The modern definition, the auditory portion of the inner ear, originated in the late 17th century. Within the mammalian cochlea exists the organ of Corti, which contains hair cells that are responsible for translating the vibrations it receives from surrounding fluid-filled ducts into electrical impulses that are sent to the brain to process sound.
The malleus, or hammer, is a hammer-shaped small bone or ossicle of the middle ear. It connects with the incus, and is attached to the inner surface of the eardrum. The word is Latin for 'hammer' or 'mallet'. It transmits the sound vibrations from the eardrum to the incus (anvil).
A middle ear implant is a hearing device that is surgically implanted into the middle ear. They help people with conductive, sensorineural or mixed hearing loss to hear.
