This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: ENT
Length of external auditory canal is ______________ 
Select and explain. 
A. 12 mm, B. 24 mm, C. 36 mm, D. 48 mm
B: 24 mm
Answer: B: 24 mm 
Explanation: Ans. B. 24 mm In adults the external acoustic meatus measures about 24 mm from the introitus to the tympanic membrane, which is its medial limit.