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Concept
Ear canal
Summary
The ear canal (external acoustic meatus, external auditory meatus, EAM) is a pathway running from the outer ear to the middle ear. The adult human ear canal extends from the pinna to the eardrum and is about in length and in diameter.
The human ear canal is divided into two parts. The elastic cartilage part forms the outer third of the canal; its anterior and lower wall are cartilaginous, whereas its superior and back wall are fibrous. The cartilage is the continuation of the cartilage framework of pinna. The cartilaginous portion of the ear canal contains small hairs and specialized sweat glands, called apocrine glands, which produce cerumen (ear wax). The bony part forms the inner two thirds. The bony part is much shorter in children and is only a ring (annulus tympanicus) in the newborn. The layer of epithelium encompassing the bony portion of the ear canal is much thinner and therefore, more sensitive in comparison to the cartilaginous portion.
Size and shape of the canal vary among individuals. The canal is approximately long and in diameter. It has a sigmoid form and runs from behind and above downward and forward. On the cross-section, it is of oval shape. These are important factors to consider when fitting earplugs.
Due to its relative exposure to the outside world, the ear canal is susceptible to diseases and other disorders. Some disorders include:
Atresia of the ear canal
Cerumen impaction
Bone exposure, caused by the wearing away of skin in the canal
Auditory canal osteoma (bony outgrowths of the temporal bone)
Cholesteatoma
Contact dermatitis of the ear canal
Fungal infection (otomycosis)
Ear mites in animals
Ear myiasis, an extremely rare infestation of maggots
Foreign body in ear
Granuloma, a scar usually caused by tympanostomy tubes
Otitis externa (swimmer's ear), bacteria-caused inflammation of the ear canal
Stenosis, a gradual closing of the canal
Earwax
Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals.
Official source
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Related concepts (9)
Otitis externa
Otitis externa, also called swimmer's ear, is inflammation of the ear canal. It often presents with ear pain, swelling of the ear canal, and occasionally decreased hearing. Typically there is pain with movement of the outer ear. A high fever is typically not present except in severe cases. Otitis externa may be acute (lasting less than six weeks) or chronic (lasting more than three months). Acute cases are typically due to bacterial infection, and chronic cases are often due to allergies and autoimmune disorders.
Earwax
Earwax, also known by the medical term cerumen, is a waxy substance secreted in the ear canal of humans and other mammals. Earwax can be many colors, including brown, orange, red, yellowish, and gray. Earwax protects the skin of the human ear canal, assists in cleaning and lubrication, and provides protection against bacteria, fungi, particulate matter, and water. Major components of earwax include cerumen, produced by a type of modified sweat gland, and sebum, an oily substance.
Outer ear
The outer ear, external ear, or auris externa is the external part of the ear, which consists of the auricle (also pinna) and the ear canal. It gathers sound energy and focuses it on the eardrum (tympanic membrane). Auricle (anatomy) The visible part is called the auricle, also known as the pinna, especially in other animals. It is composed of a thin plate of yellow elastic cartilage, covered with integument, and connected to the surrounding parts by ligaments and muscles; and to the commencement of the ear canal by fibrous tissue.