The ''malleus'', or hammer, is a hammer-shaped small bone or

ossicle The ossicles (also called auditory ossicles) are three irregular bones in the middle ear of humans and other mammals, and are among the smallest bones in the human body. Although the term "ossicle" literally means "tiny bone" (from Latin ''ossicu ...

of the middle ear. It connects with the

incus The ''incus'' (: incudes) or anvil in the ear is one of three small bones (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 i ...

, 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).

Structure

The malleus is a bone situated in the middle ear. It is the first of the three ossicles, and attached to the eardrum (tympanic membrane). The head of the malleus is the large protruding section, which attaches to the

. The head connects to the neck of malleus. The bone continues as the handle (or manubrium) 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 bone is oriented so that the head is superior and the handle is inferior.

Development

Embryologically, the malleus is derived from the first pharyngeal arch along with the ''

''. In humans it grows from Meckel's cartilage.

Function

The malleus is one of three ossicles in the middle ear which transmit sound from the tympanic membrane (ear drum) to the

inner ear The inner ear (internal ear, auris interna) 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 ...

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

Clinical significance

The malleus may be palpated by surgeons during ear surgery. It may become fixed in place due to surgical complications, causing hearing loss. This may be corrected with further surgery.

History

Several sources attribute the discovery of the malleus to the

anatomist Anatomy () is the branch of morphology concerned with the study of the internal structure of organisms and their parts. Anatomy is a branch of natural science that deals with the structural organization of living things. It is an old scien ...

and

philosopher Philosophy ('love of wisdom' in Ancient Greek) is a systematic study of general and fundamental questions concerning topics like existence, reason, knowledge, Value (ethics and social sciences), value, mind, and language. It is a rational an ...

Alessandro Achillini. The first brief written description of the malleus was by Berengario da Carpi in his ''Commentaria super anatomia Mundini'' (1521). Niccolo Massa's ''Liber introductorius anatomiae'' described the malleus in slightly more detail and likened both it and the

to little hammers terming them ''malleoli''.

Other animals

The ''malleus'' is unique to mammals, and evolved from a lower jaw bone in basal amniotes called the articular, which still forms part of the jaw joint in reptiles and birds.

Additional images

References

{{Authority control Auditory system Bones of the head and neck Ear Ossicles Otorhinolaryngology Otology Middle ear