Ear canal

Ear canal
External acoustic meatus
Ear-anatomy-text-small-en.svg
Anatomy of the human ear.
Latin meatus acusticus externus
Gray's subject #229 1036
Artery anterior part: superficial temporal artery
posterior part: posterior auricular artery
Vein superficial temporal veins, external jugular vein, pterygoid plexus
Nerve auriculotemporal nerve, great auricular nerve, auricular branch of vagus nerve
Lymph superficial cervical lymph nodes, deep cervical lymph nodes
Precursor groove (cleft) of the first branchial arch.[1]

The ear canal (external auditory meatus, external acoustic meatus) (Latin: meatus acusticus externus) , is a tube running from the outer ear to the middle ear. The human ear canal extends from the pinna to the eardrum and is about 35 mm in length and 5 to 10 mm in diameter.

Contents

Structure

The human ear canal is divided into two parts. The fibrocartilaginous 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 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.

Size and shape of the canal vary among individuals. The canal is approximately 35 mm long and 5 to 10 mm 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.

Disorders

The ear canal, because of its relative exposure to the outside world, is a common victim of diseases and other disorders. Some disorders include:

Earwax

Earwax, also known as cerumen, is a yellowish, waxy substance secreted in the ear canals. It plays an important role in the human ear canal, assisting in cleaning and lubrication, and also provides some protection from bacteria, fungi, and insects. Excess or impacted cerumen can press against the eardrum and/or occlude the external auditory canal and impair hearing.

References

  1. ^ hednk-022Embryology at UNC

Additional images

External links


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