Length of the external auditory canal is

EXTERNAL AUDITORY CANAL It starts at the external auditory meatus and ends at the tympanic membrane, where a bony structure (bony outer attic wall at tympanic membrane, where ECA ends) projects, called scutum. It is almost S-shaped curved canal of about 24 mm length. It has - outer cartilaginous part (2/3rd) and - inner bony part (l/3rd). It is directed upwards, backward and medially in the outer part and downwards, forwards and medially in the inner part. The periosteum is very firmly adherent in EAC and hence even a minor infection like a furuncle is extremely painful.