Length of external auditory canal is
Ans. c (24 mm). (Ref. PL Dhingra Diseases of ENT 2nd/pg.3)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, backwards and medially in outer part and downwards, forwards and medially in inner part.# The periosteum is very firmly adherent in EAC and hence even a minor infection like a furuncle is extremely painful.
20 mm
22 mm
24 mm
15 mm
Anatomy of External Ear & Pinna