What is the length of the external auditory canal?

The length of the external auditory canal is typically around 2.5 cm in adults. This anatomical structure, also known as the ear canal, extends from the outer ear (pinna) to the eardrum. Knowing the average length is important for a variety of reasons in audiology, such as fitting hearing instruments, understanding sound transmission, and assessing ear health.

The other lengths provided in the options do not accurately represent the average size of the human external auditory canal. While 2 cm and 1 cm are shorter than the common measurement, 5 cm is considerably longer than typical anatomical sizes. Thus, 2.5 cm stands out as the most valid and commonly accepted measurement for the length of the external auditory canal in adults.