The malleus is one of the small bones located in the middle ear. This bone strongly resembles a small hammer, and as such, is commonly referred to as the hammer of the ear. The malleus is connected to the incus, the bone in the ear that is sometimes called the anvil. The eardrum is also attached to the malleus. The primary function of this small bone is to send sound vibrations to the incus from the eardrum.
Only present in mammals, the malleus is believed to have evolved from a structure known as an articular bone. This bone is still present in tetrapods such as birds, reptiles, and amphibians. The articular bone is basically a lower jawbone that has become redundant and unnecessary in the evolution of mammals.
In the development of the mammalian embryo, the malleus forms from what is called the first pharyngeal arch. This structure becomes the pharynx in mammals and gills in fish. This arch also forms the upper and lower jawbones in mammals, clinically referred to as the mandible and the maxilla.
Injury to this bone is not particularly common, primarily due to its location in the middle ear. When injury does occur, it is usually the result of a traumatic event. Fractures resulting from a traumatic event such as an automobile accident appear to be the most prevalent cause of injury, although any type of trauma involving the middle ear has the potential to have a negative effect on the malleus.
Middle ear injuries can also occur when a foreign object is inserted into the ear. This can cause small tears, or perforations, that may lead to structural or functional damage. Blast injuries are also known to cause damage to the middle ear. Hearing loss is a major concern when there has been any kind of trauma to this area of the body. The sensitive nature of the small parts of the middle ear are particularly susceptible to damage.
Surgical intervention is the only real way to correct damage done by a traumatic injury involving the middle ear. The type of surgery involved is dependent upon the precise injury and whether or not the ability to hear properly has been compromised. Structural damage is easier to correct than functional damage. It is not always possible to restore hearing once it has been affected, although this depends largely on the type of damage causing the hearing loss.
