Length of external auditory canal is:: (A) 12 mm, (B) 24 mm, (C) 36 mm, (D) 48 mm
Answer is B. External auditory canal of an adult is 24 mm in length. Outer one-third (8 mm) is cailaginous and inner two thirds (16 mm) are bony. Cailaginous pa contains hair preventing proper visualization of drum.