1. Fundamentals of Industrial Hygiene 6th Edition
Chapter 4:
The Ears
Compiled by Allen Sullivan,
Assistant Professor, Safety and Health Management Central Washington University

2. Ear Anatomy External Ear auricle (pinna) external auditory canal
vibrissae
cerumen

3. Ear Anatomy (cont.) Middle Ear tympanic membrane ossicular chain
malleus (hammer)
incus (anvil)
stapes (stirrup)
eustachian tube
oval window

4. Ear Anatomy (cont.)
Inner Ear
cochlea
vestibular system

5. Pathology of the External Ear
Auricle (pinna)
trauma
frostbite
dermatitis and infection
Auditory Canal
foreign objects
live insects
wax impaction
narrowing of ear canal

6. Pathology of Middle Ear
Eustachian Tube
plugged v. open
Eardrum
infections
perforations/rupture
Ossicular Chain
fixation
interruption

7. Pathology of Inner Ear Cochlea Vestibular System Eighth Cranial Nerve
congenital/developmental defects
systemic diseases (MS, diabetes)
infection (mumps)
exposure to noise
exposure to toxins (medications, solvents)
circulatory problems (stroke)
trauma (concussion, skull fracture)
Vestibular System
Eighth Cranial Nerve
presbycusis
tinnitus

8. Hearing Measurement Air Conduction Testing Bone Conduction Testing
audiogram

9. Effects of Noise Exposure
Noise-Induced Hearing Loss
factors
sound level
frequency distribution
duration
temporal distribution
type of sound energy
individual differences
concurrent exposure to ototoxins

10. Non-Auditory Effects of Noise
Communication
loudness and clarity
Speech Sounds
vowels and consonants
Physiological Response
blood pressure
sleep disturbance
pregnancy
Background Noise
Quality of Life