auditory canal

n. There are two auditory canals: external and internal. The external auditory canal (or external acoustic meatus) is a slightly curved tube extending from the outer ear (pinna or auricle) to the tympanic membrane (eardrum). It is about 2.5 cm long and 0.7 cm in diameter. The internal auditory canal (or internal acoustic meatus) is an orifice near the posterior surface of the temporal lobe corresponding to its petrous portion. It is a rounded canal about 0.8 cm long and 0.4 cm in diameter. It transmits two different cranial nerves, the facial (VII cranial nerve) and the acoustic (VIII cranial nerve), and the internal auditory branch of the basilar artery. - AA