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The Eustachian tube , also known as the auditory tube or pharyngotympanic tube, is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi. ==Structure== The Eustachian tube extends from the anterior wall of the middle ear to the lateral wall of the nasopharynx, approximately at the level of the inferior nasal concha. It consists of a bony part and a cartilaginous part. A portion of the tube (1/3) proximal to the middle ear is made of bone; this bony part is about 12 mm in length. It begins in the carotid wall of the tympanic cavity, below the septum canalis musculotubarii, and, gradually narrowing, ends at the angle of junction of the squama and the petrous portion of the temporal bone, its extremity presenting a jagged margin which serves for the attachment of the cartilaginous portion of the rest of the tube,〔'(Ear - Dissector Answers ) at University of Michigan Medical School〕 and this raises a tubal elevation, the torus tubarius, in the nasopharynx where it opens. There are four muscles associated with the function of the Eustachian tube: * Levator veli palatini (innervated by the vagus nerve) * Salpingopharyngeus (innervated by the vagus nerve) * Tensor tympani (innervated by the mandibular nerve of CN V) * Tensor veli palatini (innervated by the mandibular nerve of CN V) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Eustachian tube」の詳細全文を読む スポンサード リンク
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