Сыртқы құлақ және оның құрылысы

Outer part of 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).

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. Many mammals can move the pinna (with the auriculares muscles) in order to focus their hearing in a certain direction in much the same way that they can turn their eyes. Most humans do not have this ability.

From the pinna, the sound waves move into the ear canal (also known as the external acoustic meatus) a simple tube running through to the middle ear. This tube leads inward from the bottom of the auricula and conducts the vibrations to the tympanic cavity and amplifies frequencies in the range 3 kHz to 12 kHz.

One consequence of the configuration of the outer ear is selectively to boost the sound pressure 30 to 100 fold for frequencies around 3 kHz. This amplification makes humans most sensitive to frequencies in this range—and also explains why they are particularly prone to acoustical injury and hearing loss near this frequency. Most human speech sounds are also distributed in the bandwidth around 3 kHz.

Usually, malformations are treated with surgery, although artificial prostheses are also sometimes used. Preauricular fistulas are generally not treated unless chronically inflamed. Cosmetic defects without functional impairment are generally repaired after ages 6–7. If malformations are accompanied by hearing loss amenable to correction, then the early use of hearing aids may prevent complete hearing loss.