External ear

Japanese: 外耳 - がいじ（英語表記）external ear

The outermost part of the hearing organ, consisting of the pinna and the external auditory canal, is connected to the middle ear via the eardrum. The pinna is a protrusion of skin supported by the auricular cartilage plate, and the external auditory canal is a tube with a total length of about 3.5 cm, with the outer third being cartilage and the inner two-thirds being bone. The cartilage part contains ear hair and glands. The human pinna is somewhat useful for directional sense of sound, but its sound-collecting effect is not significant. The external auditory canal also acts as a resonance chamber. The pinna is easily injured and susceptible to frostbite. Deformities such as microtia, auricles, and pouched ears, as well as deformations following trauma, are treated by plastic surgery. (→Ear)

Source: Encyclopaedia Britannica Concise Encyclopedia About Encyclopaedia Britannica Concise Encyclopedia Information

Japanese:

聴覚器の最も外側に位置する部分で，耳介と外耳道よりなり，鼓膜を介して中耳に連なる。耳介は耳介軟骨板で支えられた皮膚の突起であり，外耳道は外側3分の1が軟骨部，内側3分の2が骨部からなる全長約 3.5cmの管で，軟骨部には耳毛，耳道腺などがある。ヒトの耳介は音の方向感に多少役立っているが，集音作用は著明ではない。外耳道には共鳴腔としての作用もある。耳介は外傷を受けやすく，凍傷にもかかりやすい。小耳症，無耳，袋耳などの奇形や外傷後の変形は，形成外科的に治療する。 (→耳 )

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