The malleus or hammer is a hammer-shaped small bone or
ossicle The ossicles (also called auditory 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 ...

ossicle
of the
middle ear The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the inner ear. The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the fluid and membran ...

middle ear
which connects with the
incus 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 medi ...

incus
and is attached to the inner surface of the
eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air t ...

eardrum
. The word is Latin for ''hammer'' or ''mallet''. It transmits the sound vibrations from the
eardrum In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air t ...

eardrum
to the ''
incus 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 medi ...

incus
''.


Structure

The malleus is a bone situated in the middle ear. It is the first of the three
ossicles The ossicles (also called auditory 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
, and attached to the
tympanic membrane In the anatomy of humans and various other tetrapods, the eardrum, also called the tympanic membrane or myringa, is a thin, cone-shaped membrane that separates the external ear from the middle ear. Its function is to transmit sound from the air t ...

tympanic membrane
. The ''head of the malleus'' is the large protruding section, which attaches to the
incus 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 medi ...

incus
. The head connects to the ''neck of malleus'', and the bone continues as the ''handle of malleus'', which connects to the tympanic membrane. Between the neck and handle of the malleus, ''lateral'' and ''anterior processes'' emerge from the bone. The malleus is unique to mammals, and
evolved from a lower jaw bone
evolved from a lower jaw bone
in basal
amniotes Amniotes (from Greek ἀμνίον ''amnion'', "membrane surrounding the fetus", earlier "bowl in which the blood of sacrificed animals was caught", from ἀμνός ''amnos'', "lamb") are a clade of tetrapod vertebrates comprising reptiles (c ...

amniotes
called the
articular The articular bone is part of the lower jaw of most vertebrates, including most jawed fish, amphibians, birds and various kinds of reptiles, as well as ancestral mammals. Anatomy In most animals, the articular bone is connected to two other lower ...

articular
, which still forms part of the jaw joint in reptiles and birds.


Development

Embryologically it is derived from the first
pharyngeal arch The pharyngeal arches, also known as visceral arches'','' are structures seen in the embryonic development of vertebrates that are recognisable precursors for many structures. In fish, the arches are known as the branchial arches, or gill arches ...

pharyngeal arch
along with the
incus 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 medi ...

incus
.


Function

The malleus is one of three
ossicles The ossicles (also called auditory 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
in the
middle ear The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the inner ear. The mammalian middle ear contains three ossicles, which transfer the vibrations of the eardrum into waves in the fluid and membran ...

middle ear
which transmit sound from the
tympanic membrane (ear drum)
tympanic membrane (ear drum)
to the
inner ear Inner Ear (established in 2007 in Bodø, Norway) is a Norwegian record label initiated and led by the brothers and jazz musicians Tore Johansen and Roger Johansen. They opened Inner Ear to release their music when their former label, Gemini, clos ...

inner ear
. The malleus receives vibrations from the tympanic membrane and transmits this to the incus.


History

Several sources attribute the discovery of the malleus to the anatomist and philosopher
Alessandro Achillini Alessandro Achillini (''Latin'' Alexander Achillinus; 20 or 29 October 1463 (or possibly 1461)2 August 1512) was an Italian philosopher and physician. He is known for the anatomic studies that he was able to publish, made possible by a 13th-century ...

Alessandro Achillini
. The first brief written description of the malleus was by
Berengario da Carpi Jacopo Berengario da Carpi (also known as Jacobus Berengarius Carpensis, Jacopo Barigazzi, Giacomo Berengario da Carpi or simply Carpus; c. 1460 – c. 1530) was an Italian physician. His book "''Isagoge breves''" published in 1522 made him the most ...

Berengario da Carpi
in his ''Commentaria super anatomia Mundini'' (1521). 's ''Liber introductorius anatomiae'' described the malleus in slightly more detail and likened both it and the
incus 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 medi ...

incus
to little hammers terming them ''malleoli''.O'Malley, C.D. ''Andreas Vesalius of Brussels, 1514-1564.'' Berkeley: University of California Press, 1964. p. 120


Additional images


See also

* *
Evolution of mammalian auditory ossicles The evolution of mammalian auditory ossicles was an evolutionary event 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 ...

Evolution of mammalian auditory ossicles
*
Ligaments of malleus The ligaments of malleus are three ligaments that attach the malleus in the middle ear. They are the anterior, lateral and superior ligaments. The anterior ligament of the malleus also known as Casserio's ligament is a fibrous band that extends fr ...

Ligaments of malleus
*
Terms for anatomical location Term may refer to: *Terminology, or term, a noun or compound word used in a specific context, in particular: **Technical term, part of the specialized vocabulary of a particular field, specifically: ***Scientific terminology, terms used by scientis ...

Terms for anatomical location


References

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Category:Auditory system {{Cat main Category:Sensory systems Category:Hearing ...

Category:Auditory system