Eustachian tube
![](/Images/godic/202501/12/Middle_ear3328.png")
![](/Images/godic/202501/12/Blausen_0330_EarAnatomy_MiddleEar3328.png")
![Upper respiratory system, showing entrance to auditory tube near middle.](/Images/godic/202501/12/Blausen_0872_UpperRespiratorySystem3328.png")
![](/Images/godic/202501/12/Gray9073328.png")
The Eustachian tube /juːˌsteɪ.ʃənˈtjuːb/, 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 35 mm (1.4 in) long and 3 mm (0.12 in) in diameter. It is named after the sixteenth-century anatomist Bartolomeo Eustachi.