E.N.T

<p>General</p><p>External Auditory meatus</p><p>Cartilage ------outer 1/3<br>rd</p><p>Bone ------- Inner 2/3rds</p><p>Length 24 mm</p><p>8 mm</p><p>16 mm</p><p>2. Eustachian tube</p><p>Length 36 mm</p><p>Cartilage -----inner 2/3</p><p>24 mm</p><p>Bone -----Outer 1/3</p><p>12 mm</p><p>3. Vocal Chords</p><p>Membraneous</p><p>Cartilaginous</p><p>Length 17- 21 mm</p><p>Anterior 2/3</p><p>Posterior 1/3</p><p>4. Speech range</p><p>Hearing discomfort</p><p>500- 2000 Hz</p><p>90- 105 db</p><p>5. Normally</p><p>One can hear from 18 ft</p><p>6. Rinne’s Positive</p><p>Is Normal</p><p>7. Rinne’s negative</p><p>Conductive hearing loss greater than 15- 20 db</p><p>8. Weber’s test</p><p>Detects hearing loss of 5 db. More sensitive for conductive deafness.</p><p>9. Secretory Otitis Media</p><p>Conductive deafness of 30- 40 db</p>