<prompt> Length of the external auditory canal is20 mm22 mm24 mm15 mm  <response>: EXTERNAL AUDITORY CANALIt 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 23rd and - inner bony part l3rd.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. 